Philosophy of Plant Morphology

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Philosophy of Plant Morphology

Rolf Sattler

“Any investigation is embedded in a philosophy, any investigator uses a number of basic principles. Many conflicting theories and new developments arise from differences in these principles” (Dullemeijer 1974: IX).

"For the philosopher, science always presupposes metaphysical assumptions, of which the scientist himself is rarely aware" (book review of Canales (2017) by David Lorimer in Paradigm Explorer 2017/2, p. 63).


It is shown how morphological research is influenced by philosophical assumptions, including worldviews, and how empirical research may affect these assumptions and worldviews. The following nine worldviews are examined: essentialism, including phenomenology, mechanism, the fuzzy worldview (the continuum view), the dynamic worldview (also referred to as contextualism and process philosophy), holism or the holistic world view (also called organicism), the generating-substance worldview, animism, mysticism, and perspectivism. Goethe, “the all-embracing Goethe” (Cusset 1982), embraced all of these worldviews. However, in view of the results of modern morphological research, molecular genetics and evo-devo (evolutionary developmental biology) Goethe’s essentialism, the claim that all lateral appendages are “one and the same organ,” seems no longer generally tenable. But his demonstration of a continuum between lateral appendages and all plant organs including the stem and root (“Alles is Blatt,” i.e. all is leaf) remains a lasting and important contribution as well as his dynamic approach that emphasized processes such as expansion and contraction (“Ausdehnen und Zusammenziehen”), polarization and enhancement (“Steigerung”) in an underlying unity (wholeness). In general, among Goethe’s great and lasting contributions are his perspectivism, his dynamic and holistic outlook, his delicate empiricism, and his emphasis of the mysterious (“das Geheimnis,” “das Unbeschreibliche,” “das Unbegreifbare”). Recognizing the mystery, the challenge of present day morphology is to develop a holodynamic approach that can adequately cope with the whole diversity of plant form and in addition to the physical body of plants will also include their subtle bodies or energies that manifest in auras. When we try to fit all plant forms into mutually exclusive structural categories such as root, stem, and leaf, we will encounter forms that do not fit (misfits) because they have diverged too much from the categories. This problem or rather pseudo-problem can be overcome by the concepts of partial homology, mixed homology, combinatorial homology and a process-morphological version of the theory of anaphytosis according to which the diversity of plant form is understood in terms of branching and articulation. Branching means the formation of a new growth center, which may develop into a shoot or any other structure. It leads to articulation, the formation of articles (called anaphytes) between the points of branching. If the articles (anaphytes) are understood in terms of process morphology, we have a modern version of the theory of anaphytosis that can deal dynamically with the whole diversity of plant form including algae, bryophytes, and vascular plants. There will be no more misfits because all forms fit if they are understood in terms of branching and articulation. A unicellular organism or a simple unbranched alga consist only of one article (anaphyte), whereas branched plants constitute a system of articles (anaphytes). Individual articles as well as a whole system of articles can be seen as process combinations. This modern process-morphological version of the theory of anaphytosis may be called peaceful plant morphology because it transcends endless struggles to force misfits into one or the other category, which entails violence and has often led to animosities among plant morphologists. Perspectivism can also lead to peaceful reconciliation. Therefore, those who cannot accept the modern version of the theory of anaphytosis as a satisfactory solution may at least see it as another perspective on the diversity of plant form. Korzybski’s map analogy explained through his structural differential, Buddhist and Jaina logic as well as fuzzy logic can be very helpful in this respect.

This webpage is an elaboration of a keynote address delivered on October 6, 2017 at an international conference on
Evolving Morphology at the Goetheanum in Dornach, Switzerland, celebrating the 200th anniversary of the publication of Goethe's morphological writings (1817-1824). A condensed version of this webpage has been published under the same title in Elemente der Naturwissenschaft 108: 55-79, 2018.

I published a new book that includes an elaborate appendix "From Plant Morphology to Infinite Issues." Watch the Teaser Trailer.


Plants appear in myriad forms. Our perception and understanding of these forms (plant morphology) is influenced by philosophical assumptions and associated worldviews that are more or less projected into the manifoldness of plant form. On the other hand, our empirical investigations of plant forms may affect philosophical assumptions and worldviews. Thus, the philosophy of plant morphology examines the interrelations of philosophy and the empirical study of plant form (see, for example, Arber 1950, 1954). Before dealing with this subject matter, I would like to make a few comments on philosophy of biology.

Philosophy of Biology

I have taught philosophy of biology for many years and published a book on that subject (Sattler 1986). When I mention this to people – biologists and laypersons – I get a very common reaction: philosophy
and biology – is there any connection? Many think that since biology is a science it does not need any philosophy. However, philosophy forms a basis of biology and any other sciences. It seems impossible to carry out any scientific investigation without philosophical assumptions. These assumptions are often taken for granted and scientists may not even be aware of them. Therefore, it is one of the tasks of philosophy of science and biophilosophical investigations to make us aware of these assumptions that usually are part of a worldview. Unless one is aware of these assumptions and the associated worldview one cannot evaluate them and perhaps change them if they appear inappropriate and no longer supported by empirical evidence..

How many worldviews can we distinguish? Different authors have conceptualized them differently. Very roughly speaking, one might distinguish two major worldviews with regard to science in modern times: materialistic mechanism and holism. Both have ancient roots, both have numerous versions, and thus they may overlap. A finer and more comprehensive enumeration of worldviews can, however, be very helpful. Betty (2019), referring to Rudolf Steiner and other authors, distinguished "Twelve Ways of Seeing the World."

Pepper (1942/1970) distinguished the following seven worldviews, which he called world hypotheses:

1. The generating-substance hypothesis
2. Animism
3. Mysticism
4. Formism (also called essentialism that plays an important role in phenomenology)
5. Mechanism
6. Contextualism (the dynamic worldview)
7. Organicism (also referred to as holism)

I consider it significant that Pepper referred to these worldviews as world hypotheses. This means that they can be tested or evaluated by empirical evidence. Hence, they are not immune to change. Nonetheless, they tend to be very resistant to change for at least two reasons. First, since many or most scientists are not sufficiently aware of the philosophical assumptions of their research, it seems difficult or impossible to change them; and second, even if they are aware of their philosophical assumptions, they may identify so much with them that they will hold on to them even when they are contradicted by facts. Facts can be ignored or declared erroneous, and they may be theory-laden (see, for example, Sattler 1986, Chapters 1 and 3), which may lead to what has been called confirmation bias: we select the facts that support our view and ignore or explain away those that contradict it. It seems that Goethe was well aware of this problem when he wrote: “he [a scientist] will select from the data a few favorites that flatter him, he will manage to arrange the rest so that they will not appear to contradict him, and lastly he will complicate, obscure, and eliminate the hostile data” (Der Versuch als Vermittler von Objekt und Subjekt (written 1793, published 1823), translated by Mueller 1989, p. 224).

To give you one example, let’s briefly look at mainstream biology. What is the underlying worldview of mainstream biology? It is a materialistic mechanistic worldview, which means that a living system consists of material components that interact in a mechanistic way. Although this worldview has been successful in explaining many biological phenomena, it has limitations. Unfortunately, these limitations are not sufficiently recognized by most mainstream biologists because to a great extent mechanism has become a dogma – like a religious dogma – that is tenaciously defended. Since similar dogmatic tendencies exist also in other sciences, Feyerabend (2011) considered science a form of religion. I would call it a pseudo-religion. Sheldrake (2012), although he thinks that in principle science can be set free, showed how much mainstream science has become a belief system. He provided much evidence that contradicts this belief system, evidence that is in better agreement with the worldviews of contextualism and holism. Fortunately, there are scientists who can see beyond the dogma of mainstream science, who can practice science in an open-minded way.

Philosophy of Plant Morphology

I shall now examine the philosophy of plant morphology in terms of Pepper’s seven world hypotheses (worldviews) plus two additional worldviews: perspectivism and the fuzzy worldview (the continuum view) that could also be considered a version of organicism (the holistic worldview). I shall show how plant form is perceived and understood differently depending on the worldview implied. And I shall indicate how empirical morphological research affects these worldviews. Empirical research spans the whole range from gross empiricism to Goethe’s delicate or tender empiricism, which, as Goethe put it, “makes itself utterly identical with the object” (Goethe 1998).

Essentialism (including Phenomenology)

Essentialism and phenomenology (that implies essentialism) claim that the world, including plant morphology, is a manifestation of essences (ideas or ideal forms). Most plant morphologists don’t talk about it explicitly, but they often use mutually exclusive categories that may imply essences such as root, stem (caulome), and leaf (phyllome). Then the whole morphological diversity is forced into these categories (see, for example, Kaplan 2022, Sattler 2022, Sattler and Rutishauser 2023). This becomes obvious when a structure is encountered that does not fit. Even in that case the question is asked: Does it belong to this or that category? Which may mean: Is it essentially this or that? For example, for hundreds of years, essentialist morphologists have asked whether phylloclades are shoot, stem or leaf homologues, whether they are essentially shoots, stems or leaves (see Cooney-Sovetts and Sattler 1987).

I think that essentialism has been the most influential worldview in plant morphology. In the 20th century essentialist morphology has been spread to a great extent by Wilhelm Troll (1897-1978) and Donald R. Kaplan (1938-2007) who had many students who in turn had many students. One way to promulgate one’s ideas is by having many students. Unfortunately, morphologists using a more dynamic approach such as Karl von Goebel, Walter Zimmermann, Agnes Arber, Otto Schüepp, Serge V. Meyen, Gérard Cusset and others did not have many students or none at all and their influence was relatively minor. Pursuing this interesting topic would lead us into the sociology and psychology of science, specifically the sociology and psychology of plant morphology, which is beyond the scope of this article. I want to add, however, that essentialism has conditioned our culture and people, including morphologists, since Plato and Aristotle. Therefore, it seems that many people, including many morphologists, derive a sense of security from essentialist thinking and often defend it tenaciously even in view of contradictory evidence.

Troll acknowledged explicitly the essentialist philosophical foundation of his morphological work. Kaplan adopted an evolutionary approach, but he kept asking the same either/or questions an essentialist would ask. Troll, Kaplan, and their many students and followers made enormous contributions to our knowledge of plant form. Troll’s
Vergleichende Morphologie der Höheren Pflanzen (1937-1943) remains fundamental up to the present day, although constrained by the essentialist presupposition (for Troll’s biography, his morphology and publications see Nickel 1996). Kaplan's Principles of Plant Morphology (Kaplan 2022) is a monumental opus that can be considered a modern rendition of Troll's work (see Sattler 2022).

Karl von Goebel was Troll's thesis director and Adriance S. Foster Kaplan's. Both Goebel and Foster pursued a more dynamic approach to morphology and could see beyond the strictures of essentialism at least to some extent. Foster even appreciated the dynamic theory of anaphytes (see Cusset 1982, p. 46 and below). However, both Troll and Kaplan seemed unable to understand and appreciate the more dynamic insights of their thesis directors and thus they remained trapped in the static strictures of essentialism.

Troll was deeply influenced by Goethe’s morphology (Goethe 1790, 1817-1824). To a great extent Goethe’s morphology can be considered essentialist when he emphasized the essential similarity or sameness of all lateral appendages by pointing out that in all their manifold manifestations they remain always one and the same organ, “ein und dasselbe Organ” (Goethe 1817, Die Metamorphose der Pflanzen, Section. 4). Thus Goethe indicated an organ identity, the leaf.
He understood the leaf as a proteus that changes in many ways and yet remains in its essence the same (“verwandelt sich stets und bleibt doch im Wesen derselbe,” according to Toll 1926, p. 60). Troll (1926, p. 59) referred to it as “Urblatt,” but Goethe called it simply “Blatt” (“leaf”), although he would have preferred a more general term that would have underlined that he had in mind a primal phenomenon, an “Urphänomen” (see Troll 1927, pp. 73-88, Goethe 1817, Die Metamorphose der Pflanzen, Section 120). With regard to the primal phenomenon of the whole plant, the “Urpflanze,” he emphasized that it is an “essential form” (“wesentliche Form”) (quoted by Troll 1926, p. 51). According to Mayr (1982), Goethe's essentialism in a way "was a fusion of Plato’s essentialism with aesthetic principles…which is why it had such an appeal during the romantic period.” It seems, however, that Goethe's essentialism was much closer to Aristotle's, according to which essences reside in objects and not in an unseen "heaven" as in Plato's essentialism. Thus for Goethe and Aristotle the seen appearances were very important. In this context Bortoft (2012) referred to "Taking appearances seriously." Bortoft (1996, p. 21) thought, “that Goethe could be described as a phenomenologist of nature.” But Goethe also used an empirical hypothetico-deductive approach. He wrote, “my whole procedure rests upon deduction” (see Mueller 1989, p. 237) and “if…a case appears that contradicts my law, I know I must pass on and search for a higher viewpoint” (Erfahrung und Wissenschaft, translated as Experience and Science by Mueller 1989, p.228). Yet he also stressed that he gained his knowledge through “Anschauende Urteilskraft” (intuitive judgement, see below), in short, through “Anschauung,” which “may be held to signify the intuitive knowledge gained through contemplation of the visible aspect” (Arber 1950, p. 209). According to Portmann (1953), “Anschauung” implies a holistic, reverential and awe inspiring approach that deeply relates or identifies with the object and acknowledges its mysteriousness. This need not imply essentialism. However, according to Troll (1926, p. 77) “Anschauung” penetrates to the core of appearance, to its essence, its ideal form. Phenomenology, at least as Husserl envisaged it, also includes essentialism. Barbara McClintock was more modest but took a contemplative stance and emphasized the importance of identification with and “a feeling for the organism” (Keller 1983).

“One phrase that Goethe used to describe his method was
delicate empiricism (zarte Empirie) – the effort to understand a thing’s meaning through prolonged empathic looking…He thought to use firsthand encounter directed in a kindly but rigorous way to know the thing in itself (Seaman 1998). However, in his Critique of Pure Reason, Kant has shown that we cannot know the thing in itself. And even if we could know the thing in itself, we could not describe it through language as Korzybski has so clearly demonstrated by his Structural Differential (see below). Richter (2012) concluded that Goethe, like Kant, did not claim to grasp the thing in itself. She thought, however, that, as Goethe pointed out, one can develop a pure intuition of nature (“reine Anschaung”). Although Goethe advocated “reine Anschauung,” he also used language and concepts compatible with modern empirical science. Thus, he referred to the “Urpflanze” as a “model” and a “general formula” (“allgemeine Formel) (see Gleißner 2005, p. 54). Furthermore, he referred to his conclusion that, “Alles ist Blatt” (“All is leaf”) as a “hypothesis,” not as “reine Anschauung” (see Troll 1926, p. 52). This contradicts a common claim that Goethe’s morphology relied solely on “Anschauung” and thus was free of hypotheses and models (see Goetheanismus in

Goethe began his
Metamorphosis of Plants with the following empirical statement: “Anyone who devotes the least attention to the growth of plants can easily note that certain of their external parts are often transformed, assuming, either completely or to some lesser degree, the form of the neighbouring parts” (Goethe 1790, Die Metamorphose der Pflanzen, Section 1, translated by Mueller 1989, p. 31). This statement is well supported by modern empirical research. But then, in the fourth section of his Metamorphosis of Plants, he introduced his guiding essentialist view when he wrote that, “the process by which one and the same organ [the leaf, the “Urblatt”] makes its appearance in multifarious forms has been named the metamorphosis of plants” (ibid). Thus the “original identity” of all lateral appendages, their essence, their true nature, became a cornerstone, the foundation of his morphological outlook in his Metamorphosis of Plants. Nonetheless, he did not remain completely confined to it. He wrote: The researcher shouldn’t confine himself within one uniform mode of explanation” (quoted by Cusset 1982, p. 27). With regard to the notion of the type that was central in his essentialist morphology, Goethe stated that this “idea, which I prize so much, can be considered as a conducting thread facilitating discoveries, but that it is of no help in determining particular cases, and in fact, is a hindrance” (ibid.). And yet in reading Kant’s Critique of Judgement, he considered the possibility of “intuitive judgement” (“anschauende Urteilskraft”): “Through contemplation [Anschauen] of ever-creative Nature we might make ourselves worthy of participating intellectually in her productions. Had not I myself ceaselessly pressed forward to the archetype, though at first unconsciously, from an inner urge; had I not even succeeded in evolving a method in harmony with Nature?” (Anschauende Urteilskraft (written 1817, published 1820), translated as Intuitive Judgement, ibid, p. 233). So he thought that experience and knowledge, experience and idea can be one as it is maintained in phenomenology that implies essentialism. But in the same year he also wrote: “I fully agreed with those of my friends, who, with Kant, maintained that even though all our knowledge concerns experience, it does not necessarily arise from experience” (Einwirkung der neueren Philosophie (written 1817, published 1820), translated as Influence of the New Philosophy, ibid, p. 229). This statement contradicts phenomenology according to which ideas and knowledge arise in experience as emphasized by Steiner (1962, p. 11) and other Goethe interpreters. One year after Goethe made the above statement he reiterated it even more forcefully when he concluded “that a definite chasm seems to be fixed between idea and experience. Our efforts to overbridge the chasm are forever in vain, but nevertheless we strive eternally to overcome this hiatus with reason, intellect, imagination, faith, emotion, illusion or – if we are capable of nothing better – with folly” (Bedenken und Ergebung (written 1818, published 1820), translated as Indecision and Surrender by Mueller 1989, p. 219). Thus, just one year after having written his short essay on Intuitive Judgement, he acknowledged that, “the duel [conflict] between the perceived [by the senses] and the ideated remains forever unresolved” (ibid, p. 219). To alleviate this conflict Goethe wrote that he took flight (“flüchtet”) into the realm of poetry, into the realm of aesthetics, of awe and wonder of the holy mystery:

Zum erstaunen bin ich da
(Clothed in wonder I am here)
(from Parabasis, translated by Aldyth Morris)

So schaut mit bescheidnem Blick
Der ewigen Weberin Meisterstück
(Regard with silent wonder
The eternal weaver’s masterpiece)
(from Antepirrhema, translated by Aldyth Morris)

So ergreifet ohne Säumnis
öffentlich Geheimnis
(Thus will you grasp, with no delay
The holy secret, clear as day)
(from Epirrhema, translated by Christopher Middleton)

Nature (A Fragment) he referred to love as her crown and in his poem on The Metamorphosis of Plants, in addition to the eternal and secret law, he praised holy love and the divine hand of the goddess.

And he wrote, “He to whom Nature begins to reveal her open secret will feel an irresistible yearning for her most worthy interpreter, Art" (Goethe 1998; see also Gray 1994).

Thus, beyond poetry we can, of course, appreciate aesthetics also in the visual arts and music. Even in science we may find an aesthetic dimension, which should not be neglected. “The aesthetic of science deserves more attention if science is to be seen in all its richness (Flannery 1992, p. 423). In morphology, science, philosophy, and aesthetics (the arts) may converge; and as I shall show below in the sections on animism and mysticism, even spirituality may be included in this convergence.

The above quotations show that although Goethe was attracted to intuitive judgement and phenomenological thinking that implies essentialism, he was also critical of them and went beyond them. Therefore, contrary to many Goethe interpreters such as Steiner (1884), Troll (1926), and Bortoft (1996, 2012), Goethe embraced many philosophies and methods and even went beyond them, and thus Cusset (1982, p. 24) referred to the "all-embracing Goethe." In contrast, Troll seemed completely enslaved in essentialism that he elaborated in a typology in which types represent essences. Troll used the classificatory type concept that supports the idea of an essence. In contrast, according to the non-essentialist concept of the extreme type, types may be continuous and therefore compatible with continuum morphology (
Sattler 1996, Fig. 1).

Evolutionary morphologists such as Kaplan also use the classificatory type concept and therefore ask either/or questions like essentialists. Froebe (1971), however, showed that the type concept can be understood as a model, a hypothetical construct that does not entail essentialism. Although plant morphology can be pursued in this fashion (see, for example, Claßen-Bockhof 2001a), essentialism may return in more or less subtle forms through either/or questions. Such questions are often framed in terms of homology. Homology has been called “morphology’s central conception” (J. Huxley in de Beer 1928). Originally, it was defined as “essential similarity, which implied 1:1 correspondence” (see Sattler 1984, Minelli 2016). Owen is usually given credit for having explicitly and systematically introduced the term homology as essential similarity or sameness. With regard to animals, he defined a homologue as “the same organ in different animals under every variety of form and function” (Owen 1843, p. 379). So how can we determine what is the same organ? Owen used the criterion of relative position. In plant morphology this criterion is also much used. But homeosis (replacement) has undermined its general validity. For example, a root replacing an axillary branch in
Nasturtium officinale is not considered homologous with a branch in spite of the same relative position (see Champagnat and Blatteron 1966). In this case the special quality of the root is considered a more important criterion to determine its homology. But if one wants to define homology only in terms of relative position as, for example, Claßen-Bockhoff (2005) and Hagemann (2005) uphold, then it would be more appropriately referred to as homotopy. And homology defined by the criterion of special quality could then be referred to as homomorphy as Zimmerman (1959, p. 658) implied long ago. (Since the prefix ‘homo’ literally means ‘the same,’ it appears confusing that Claßen-Bockhoff (2005, p. 43) defined homomorphy as analogous similarity).

Besides the homology criteria of relative position and special quality, the criterion of transitional forms is often used (Remane 1952). Goethe used it in his
Metamorphosis of Plants to homologize lateral appendages such as stamens with petals. As I see it, this criterion can only show a continuum but not homology as sameness or identity. Consider the following series of transitional forms, each of which exhibits three of the properties a,b,c,d,f:
1. abc
2. bcd
3. cde
4. def
1 and 4 share none of their properties. So how can they be homologous, how can they be essentially the same? They are related through transitional forms, but that does not mean that they are homologous in the sense of essential similarity, sameness, or identity. Even the first three forms, although they could be defined by property c (as a category, for example), show only a partial correspondence; they are not the same. Deducing sameness from a continuum of forms appears to be fallacious reasoning. In as much as Goethe based his
Metamorphosis of Plants on this fallacious kind of reasoning of sameness, it does not make sense to me. Modern research has shown that the lateral appendages are not necessarily the same and therefore Goethe’s basic dictum in his Metamorphosis of Plants that all lateral appendages are “one and the same organ” is not supported. And even Goethe himself in at least a few comments recognized that compound leaves are not the same as simple leaves (see below). Thus section 4 of his Metamorphosis of Plants where he stated that all lateral appendages are “one and the same organ” can be deleted (I think with Goethe’s consent). Nonetheless, I think that the Metamorphosis of Plants by pointing out a continuum of the lateral appendages demonstrates one important aspect of the relationship of these appendages, namely the continuum (see Vine 2015). As I shall indicate below, a continuum has also been demonstrated between lateral appendages (phyllomes) and stems (caulomes), shoots, and even trichomes.

Wittgenstein (1953/2009) referred to family resemblances in groups where we can see connections, although we may be unable to define them in terms of common properties. Beckner (1959) formalized such relationships and referred to them as polytypic concepts. A fully polytypic concept cannot be defined by any property. Beckner pointed out that many biological classes are polytypic or fully polytypic (for an example see Sattler 1986, p. 83). Instead of ‘polytypic’ the word ‘polythetic’ is also used; it refers to the same concept.

If “metamorphosis” is understood not in terms of identity but simply as transformation that does not imply sameness, then it becomes a valid concept. And in as much as Goethe in his
Metamorphosis of Plants has demonstrated many important transformations he has made an important contribution to plant morphology.

Now back to homology. Instead of defining it as essential similarity or sameness, evolutionary morphologists usually define homology in terms of evolutionary descent so that homologous structures can be considered as those structures that are phylogenetically derived from the same structure in a common ancestor. The problem with this approach is that the methodology used to establish the phylogenetic derivation tends to imply a hidden essentialism or at least 1:1 correspondence (see Sattler 1984). Note how even nowadays molecular geneticists often refer to organ identity – philosophical relics from the past. It seems that morphology, other sciences and our culture have been haunted by the ghost of Plato and Aristotle, the ghost of sameness and identity in a world where we can only find similarity and difference, although the similarity may sometimes come close to sameness at least for practical purposes and for a limited time (see also Craw and Heads 1988). Therefore, Dupré and Nicholson (2018) concluded that, "essentialism - at least as far as the living world is concerned - is untenable." To put it less categorically, we may say that empirical research does not support the general validity of essentialism. But I think it may be of limited heuristic value. For example, although Goethe recognized that his idea of the sameness, the identity of all lateral appendages was untenable, it helped him to see a continuum among these appendages.

Besides the danger of an implicit essentialism or 1:1 correspondence, another problem of much evolutionary morphology is that, contrary to what is often said, structures are not directly derived from one another in a strict genealogical sense: organisms give rise to one another, but not structures (see Sattler 1994, Fig. 7). Although this seems obvious, it has often been ignored, but now it seems to be increasingly recognized in evo-devo (evolutionary developmental biology): ontogenies change during evolution. Zimmermann (1930/1959) knew this long ago when he emphasized hologeny, which refers to the continuum of successive ontogenies. He saw clearly that evolution involves the transformation of ontogenies. Kupiec (2009) referred to ontophylogenesis. Consequently the change of whole ontogenies needs to be compared (not just isolated structures that supposedly have a 1:1 correspondence), and then we notice that this change may lead to transformations that supersede 1:1 correspondences and lead to partial correspondences, which require the concept of partial homology. I proposed a partial homology concept (as a semi-quantitative homology concept) over 50 years ago (in 1966), but it was not well received by many typologists and evolutionary morphologists who, like typologists, insisted that all homology must be total, that is, 1:1 correspondence (or essential similarity). However, "taking distance from the traditional, all-or-nothing approach according to which two structures are either homologous or nonhomologous, since the '80s of the past century several authors have been defending the view that all assessments of homology are by necessity partial" (Minelli 2016). Research in evo-devo has provided further corroboration for this view (Minelli and Fusco 2013). Now we have much evidence for partial homologies even at the molecular level. For example, during the development of the phylloclades of
Ruscus aculeatus genes are expressed that are normally expressed in the shoot apex and leaves (Hirayama et al. 2007), which is compatible with the morphological conclusions of Cooney-Sovetts and Sattler (1987) that these phylloclades are partially homologous to shoots and leaves. Also on the basis of molecular genetic research, Eckardt and Baum (2010) concluded that, “it is now generally accepted that compound leaves express both leaf and shoot properties.” Agnes Arber knew that long ago, without evidence from molecular genetics, when she proposed her partial-shoot theory of the leaf (Arber 1950). It was also evident from many purely morphological studies of leaf development (see, for example, Rutishauser and Sattler 1997, Lacroix et al. 2003). Furthermore, in many other cases the notion of partial homology appears more appropriate than that of traditional total homology (see, for example, Rutishauser and Isler 2001, Rutishauser 2016, Prenner and Rudall 2007, Prenner et al. 2011). Because of the mixing of traits and gene expression of different structures, some authors referred to “mixed homology” (see Rutishauser 2005, p. 132). Minelli (1998, 2016) referred to factorial or combinatorial homology. We can conclude then that purely morphological research and evidence from molecular genetics undermine essentialism and the exclusive insistence on the concept of traditional homology (1:1 correspondence), which, however, does not mean that essentialism and the notion of traditional homology are totally useless. Within the broader framework of evo-devo they may remain useful where evidence for 1:1 correspondence exists. In fact, total homology can be seen as a special case of a quantitative homology concept when the homology is 100% (see below in the section on The Fuzzy Worldview or the Continuum).

The notions of partial homology, mixed homology, and combinatorial homology transcend essentialism and are more in line with other worldviews. But before I turn to these other worldviews I want to comment on the meaning and the use of categories. Essentialists understand categories such as root, stem and leaf as realities. On the other hand, nominalists use categories only as conceptual tools that lack an inherent reality. A third way of using categories – the middle way – is in terms of Korzybski’s map analogy: they are considered a map that refers to the territory of reality. Obviously, as
Korzybski has so well demonstrated through his Structural Differential (see Stockdale), “a map is not the territory” (Korzybski 1994). But a map, especially a good one, can represent important aspects of the territory of reality. Thus, if we consider the root-stem-leaf framework of mainstream morphology, we can say that it represents important aspects of plant morphology, but not the territory of reality because “whatever you might say something "is", it is not” (Korzybski 1994). Whatever you might say belongs to the verbal level and not to the un-speakable reality. Hence, whatever you might say a plant form “is”, it is not. Its ultimate reality remains shrouded in mystery, a mystery, which includes both the observed and the observer.

Postmodernism also recognizes the limitation of everything that is expressed through language. A central concept of postmodernism is deconstruction, which shows the limitations of tenets that claim to be true. Many people consider deconstruction negative or even nihilistic because it shows the relativity of everything expressed through language. I find it liberating because it removes the illusion that absolute truth can be communicated though language. Absolute truth, if we can grasp it or be it, remains unnamable (see also Craw and Heads 1988).
Integral Philosophy tries to integrate the unnamable and the namable (
Sattler 2010, Chapters 7 and 8).


According to mechanism, living systems consist of material components that interact mechanistically as it is the case in machines. This worldview still dominates mainstream biology and morphology. Essentialism no longer dominates explicitly; but although in mechanism the emphasis is on particulars, categories are used, and these categories may be the same as those of essentialist morphologists. Thus, the categories root, stem, and leaf are used that Troll and his essentialist predecessors espoused as essences. Hence, one could say that to some extent mechanistic materialistic morphology represents a hidden essentialism. However, as I pointed out, categories can also be used in a non-essentialist way. But even then the implied logic is often Aristotelian either/or logic, which leads to the same kind of questions that essentialists would ask: Is it this or that? For example: Is this structure a leaf or a stem? Thus we come to the surprising conclusion that although essentialism and mechanism are very different worldviews, in as much as they use mutually exclusive categories they give us a fragmented view of plant form. And not only may the categories of mechanism resemble those of essentialism or even be identical with them, according to Schilperoord (2007), the categorical framework of essentialists like that of Troll has a fundamentally atomistic character. Furthermore, essentialism and mechanism share a reductionist methodology: they both reduce the diversity of plant form to mutually exclusive categories. Or, in other words, the diversity of plant form is accommodated in or derived from basic categories. In contrast, the worldviews of contextualism and holism can overcome this fragmentation at least to some extent. Contextualism and holism have various versions. Some may be compatible with materialism; others go beyond it (see below).

Evo-devo, although materialistic, has the potential to overcome fragmentation to some extent. It still tends toward reductionism and a structure-process duality (see below).
MorphoEvoDevo (Wanninger 2015) emphasizes the important morphological aspects of evo-devo. Inclusion of the environment would expand evo-devo to eco-evo-devo (Tauber 2010). The continuum of energy fields in and around plants also would have to be included eventually (see below).

To a great extent we find a mechanistic worldview in functional morphology, and in the relation of morphology to other disciplines such as genetics, physiology, ecology, and technology (see Claßen-Bockhoff 2001a). However, any branch of morphology may be more or less informed by different philosophical backgrounds. For example, developmental morphology may be tainted by essentialism or pursued mechanistically or even contextually and holistically. The same can be said for evolutionary morphology and other branches of morphology.

Before I turn to other worldviews, a few comments on Linné and Goethe. Linné saw nature and plant morphology as God’s creation. But his approach to the study of plant form and diversity was rather mechanical following Aristotelian either/or logic. In contrast, Goethe was fascinated by the organic holistic and dynamic view of nature. He wrote that, “Trennen und Zählen lag nicht in meiner Natur” (see Troll 1926, p. 193), which means that separating and counting – so typical of mechanism – was not in his nature. Nonetheless, he acknowledged that Linné’s more mechanistic approach was also necessary (see Troll 1926, pp. 199, 227); in fact, he used many terms from Linné’s morphological vocabulary and emphasized that after Shakespeare and Spinoza Linné had the greatest influence on him (see Troll 1926, p. 43). He also noted that an atomistic view of nature couldn’t be totally dispensed with (see Troll 1926, p. 235). According to Kirchoff (2002, p. 80)), Goethe "unites reductionist and holistic approaches."

As far as I know, Goethe did not reframe his essentialist
Metamorphosis of Plants in mechanistic materialist terms. But it could be done. Instead of saying that, “one and the same organ makes its appearance in multifarious forms” (Metamorphose der Pflanzen, Section 4, translated by Mueller 1989, p. 31), one could refer to a common pattern. Such reference can be based on observations, whereas the intuition of an essence that constitutes the so-called identity of all lateral appendages remains non-observable. Referring to a pattern would also have the advantage that one could investigate changes in the pattern and how it relates to other patterns like those of a typical stem or shoot. Thus research would not remain stuck in an unchangeable eternal essence of the lateral appendages. For example, with regard to structures of the androecium, one could find out that some resemble the leaf pattern, whereas others approach the stem and short shoot pattern (see, for example, Rutishauser and Sattler 1985, Sattler 1988). A semblance of the short shoot pattern is evident in the androecium of plants such as Hypericum hookerianum where in the axils of the petals androecial fascicle primordia arise that then produce the primodia of individual stamens (Leins 1983, Leins and Erbar 2010). Such a pattern contradicts the idea that a flower is always a modified monaxial shoot and therefore it cannot be sufficiently understood in terms of Goethe’s essentialist Metamorphosis of Plants or an evolutionary morphology that is still caught in the classical theory according to which all flowers are modified monaxial shoots (Sattler 2017). However, without taking recourse to morphological categories, patterns that do not fit the classical theory of the flower may be best described in terms of process morphology (see below) and a modern process-morphological version of the theory of Anaphytes (see below).

Gynoecial morphology is also more diverse than envisaged in terms of the classical theory of the flower. In several taxa the placenta and/or ovule(s) may be independent of the enclosing appendage (Croizat 1961, 1964, Sattler 2017). Even the typical carpel that bears the placenta appears to be a compound structure according to some evidence of molecular genetics (Michael Heads, manuscript in preparation).

Although Goethe is considered the founder or one of the founders of the classical monaxial theory of the flower that still dominates modern plant biology, he made some comments that point beyond that theory. At the end of his life in his Maxims in Prose he wrote: "The pistil, the receptacle, and the fruit all belong to the system of the eyes [i. e. branches]" (quoted by Cusset 1982, p. 27), which means that the pistil is not just an appendage or appendages, but the homologue of a branch or branches. As a result with regard to the gynoecium, the flower becomes a polyaxial system. Also, already in
The Metamorphosis of Plants (Section 87), Goethe wrote: "It is well known that the activity of such a bud [that develops in the axil of a leaf] has a great similarity to that of the ripe seed" (see also Schilperoord 2011, pp. 113-114). Again, this means that since a seed, like a bud, includes a secondary axis, the flower becomes a polyaxial system at least with regard to the gynoecium. As buds in the vegetative region usually develop in the axils of leaves, ovules and seeds may develop in the axils of gynoecial appendages (see, for example, Pauzé et Sattler 1979) or more commonly on the carpels just as occasionally buds may be formed on leaves (see Dickinson 1978). Goethe also recognized the "fruitfulness which lies concealed in the leaf" (The Metamorphosis of Plants, section 76), in other words, the phenomenon of epiphylly. Ovules developing on carpels can be seen as a phenomenon of epiphylly. In cases where only one ovule is formed in continuation of the main axis of the flower, the flower appears monaxial (see, for example, Macdonald and Sattler 1973, Sattler and Lacroix 1988). Hence we could distinguish monaxial and polyaxial flowers with regard to the gynoecium. As I pointed out above, members of the androecium may range from typically phyllomic to more or less stem-like or short shoot-like. Hence with regard to the androecium flowers may range from monaxial to more or less polyaxial (Sattler 1988).

The Fuzzy Worldview (The Continuum View)

The fuzzy worldview can be considered a version of the holistic worldview (organicism) or a separate worldview. Kosko (1993) considered it a separate worldview in his book
Fuzzy Thinking. The New Science of Fuzzy Logic. He concluded that upon closer inspection almost everything in our world becomes more or less fuzzy, which means continuous, without sharp borders. Thus the colours of the rainbow fade into each other. Clouds, winds, and storms have no sharp borders. The seasons gradually merge one into the other. The meaning of words often is not sharp. Right and wrong have many meanings. The same can be said for fairness, reasonability, guilt, malice, threat, etc. (see also Sattler 2016, Chapter 3). Even worldviews appear fuzzy. Goetheanism and Goethean science appears fuzzy. There seems to be a continuum between Goethean science and modern philosophy of science (Froebe 1971), between Goethe’s delicate empiricism and ordinary empiricism. For example, Seaman (1998) claimed that Goethe could apprehend the essence of things, the thing in itself. Richter (2012) did not accept this conclusion but thought that Goethe could reach an intuitive understanding. And Kirchoff (2002) showed that Goethe united holistic and reductionist approaches, which connects him to modern empiricism. Finally, there is much evidence of fuzziness in plant morphology, which therefore may be called fuzzy morphology. Honouring Agnes Arber who emphasized fuzziness, Rutishauser and Isler (2001) referred to Fuzzy Arberian Morphology (FAM).

The fuzzy worldview deconstructs boundaries that, as Portmann (1965, p. 219) pointed out, are always difficult to draw and entail violence. Thus, the fuzzy worldview can be seen as a peaceful worldview. It requires fuzzy logic (Kosko 1993). In contrast to Aristotelian either/or logic, fuzzy logic admits membership in a set (or category) by degree, ranging from 0% to 100%. A 0% leaf is, of course, no leaf at all, whereas a 100% leaf is a typical leaf (phyllome) exhibiting all of its typical properties (see Rutishauser 2005, p. 142, Rutishauser and Sattler 1985). Structures such as phylloclades are located somewhere between the two extremes. Quantitative homology can express the degree of homology in terms of morphological distance from the typical structures (
Sattler and Jeune 1992).

According to fuzzy morphology, morphological categories form a continuum (Sattler 1994,
Rutishauser and Isler 2001). This continuum was confirmed through multivariate analysis (Sattler and Jeune 1992, Jeune and Sattler 1992, Cusset 1994, Sattler 1994, Jeune et al. 2006). It also includes the appendages of flowers (Sattler 2017). In Euphorbia Prenner and Rudall (2007) demonstrated a continuum between inflorescence, flower, and floral organs, which was also supported by genetic molecular data (Prenner et al. 2011).

As long as we deal only with typical forms, classical categorical morphology works well (see Rutishauser and Isler 2001). However, if we want to include structures that do not fit the categories (so-called misfits), fuzzy morphology is required. In other terms, Nägeli knew that already in 1844 (see Schüepp 1933). Other morphologists agreed (see Cusset 1982). For example, Potonié (1912) emphasized that it is impossible to accommodate every organ in “dogmatisch fixierten Kategorien” (dogmatically fixated categories), and he referred to C. H. Schultz who already in 1843 decried the notion of general organ categories that fit all plant organs as an “Irrtum der Botanik” (error of botany). In 1871 in his Habilitation, Pfeffer defended the thesis that “root, shoot, leaf, and hair are not mutually exclusive: transitional forms connect them with each other” (quoted by Bünning 1977, p. 8). Yet during the history of plant morphology pages and pages have been written in a futile attempt to force transitional forms and other “misfits” into the categories. Braun (1851, p. 120) insisted that the sharp distinction of root, stem, and leaf, which he considered the fundamental organs, are the foundation of plant morphology. He influenced many plant morphologists up to the present time and as a result nearly endless debates and quarrels about misfits ensued.

In fuzzy morphology misfits are not problematical. In fact they are not misfits. They just belong to one or the other category to some degree. So one would think that fuzzy morphology would be easily accepted, especially since it resolves almost endless disputes for structures that do not fit the categories. But there is enormous resistance to fuzziness for several reasons. First, most people, including scientists, don’t like the words ‘fuzzy’ and ‘fuzziness.’ But these words could be replaced by ‘continuous’ and ‘continuum,’ which have the same meaning. So instead of ‘fuzzy morphology’, I usually refer to ‘continuum morphology’ (
Sattler: Plant Morphology). Another reason why fuzzy morphology and even continuum morphology often have been rejected seems cultural. Since Plato and Aristotle our culture has been deeply imbued with essentialism and either/or thinking so that it has almost become a habit to think in terms of categories and either/or logic. Fuzzy logic is considered vague and imprecise because it is not categorical. However, in fact it is much more precise than either/or logic because it specifies quantitatively the degree of membership in a set. Unfortunately, everyday language (with words that refer to individual or class concepts) is not well suited to represent fuzziness. It tends to fragment the continuum of reality and to a great extent conditions us to perceive a fragmented world.

Goethe “dachte sich alles Lebendige am liebsten als Kontinuum” (Muschg in Wyder 1999, p. 188), which means that he preferred to think of all life as a continuum. He wrote: “da verlor ich den Mut, irgendwo einen Pfahl einzuschlagen, oder wohl gar eine Grenzlinie zu ziehen” (quoted in Toll 1926, p. 46), which means that he did not want to fragment the natural continuum by drawing boundaries. In his statement “Alles is Blatt” (All is leaf), he even went beyond the root-stem-leaf fragmentation of classical morphology (see below). However, it seems that in his
Metamorphosis of Plants (1790, 1817) he restricted the continuum to the lateral appendages; and therefore in the parts of the flower he recognized only the identity, the essence, of the leaf. This interpretation of the flower appears rather one-sided and incomplete because it is only partially supported by empirical developmental evidence (Sattler 2017, Heads, manuscript in preparation).

The Dynamic Worldview (Contexualism and Process Philosophy)

Besides essentialism, mechanism and the fuzzy worldview, there are other worldviews that are important in plant morphology. A very important one is the dynamic worldview, also referred to as contextualism and process philosophy (Whitehead 1929, Woodger 1967, Nicholson and Dupré 2018, and others). According to this worldview, process is primary and fundamental; everything is dynamic; everything changes (sooner or later, fast or more slowly). As essentialism and mechanism, the dynamic worldview has ancient roots. In western culture we find it, for example, in Heraclitus’ panta rhei (everything flows). In the East it has been even more important: in the I Ching (The Book of Changes), in Daoism where it is recognized that all things change, and in Buddhism where impermanence is considered the hallmark of existence.
Goethe expressed the wisdom of impermanence poetically:

Und so lang du das nicht hast,
Dieses: Stirb und werde!
Bist du nur rein trüber Gast
Auf der dunklen Erde.

(And until thou truly hast
This “dying and becoming,”
Thou art but a troubled guest
O’er the dark earth roaming).

The closer we look, the more dynamic the world becomes. Plant morphology emphasizes dynamics in ontogeny and phylogeny. But usually this dynamics is limited due to a structure-process dualism and the subject-predicate (noun-verb) structure of our language. What do I mean by structure-process dualism? We normally single out a structure such as a leaf and then we study the processes that occur within this structure. Then we recognize that the structure changes as a result of the processes within it, but we still consider it the same kind of structure, we still consider it a leaf in this example. And this constitutes a static aspect that is often overlooked. But as Dupré and Nicholson (2018) pointed out, "the world - at least in so far as it concerns living beings - is not, as philosophers [and biologists] have overwhelmingly assumed, made up of substantial particles or things [including structures], but of processes."

To render morphology and biology more dynamic we have to see structure itself as process. Then there is only process and therefore the structure-process dualism is overcome. Woodger communicated this insight very well when he wrote: “It seems, then, that what is required is an enlargement of our concept of ‘structure’ so as to include and recognize that in the living organism it is not merely a question of spatial structure with an ‘activity’ as something over against it, but that the concrete organism is a spatio-
temporal structure and that this spatio-temporal structure is the activity itself” (Woodger 1967, p. 330). In short: structure itself is process. Now this is easily said, but implementing it seems very difficult, at least to me. Nonetheless, I think I succeeded doing it at the end of my professional life before I retired, and this lead to a more dynamic morphology. I refer to it as process morphology to emphasize that process is fundamental and primary. I think it achieved what Woodger had in mind.

In process morphology, instead of starting with structures such as root, stem, and leaf (that could lead to the structure-process dualism), I started with the following 4 fundamental processes:
growth and decay
differentiation and dedifferentiation
Then I distinguished different parameters (modalities) for these four processes (see
Sattler 1990, 1994). One of the growth parameters is symmetry (symmetrisation). Thus, when a structure grows radially it assumes the symmetry characteristic of a root or stem, whereas when it grows dorsiventrally it assumes the symmetry of what we call a leaf. The parameters are fuzzy so that the whole observable range of symmetries is covered. As a result of this approach structures can be seen completely dynamically as process combinations. Thus, what changes during ontogeny and phylogeny are process combinations. Taking into account the fuzziness (continuum), plant morphology can then be seen as a dynamic continuum.

Two processes that I ignored in my publications are folding and unfolding. These processes often occur in later stages of leaf and flower development and to some extent may be even seen with the naked eye. The Japanese art of
Origami is an art of folding that has inspired modern methods of modelling such as the folding of leaves, and it has led to sophisticated folding procedures in biology, medicine, engineering, architecture, and other fields.

Since traditional morphology has become increasingly dynamic with more and more emphasis of processes, I have been told that process morphology does not add anything fundamentally new. However, process morphology entails a fundamental departure from traditional dynamic morphology because in the latter structures and structural categories are primary, whereas in process morphology process is primary and structures are seen as process combinations. Thus, process morphology represents a complete reversal of the relation between structure and process, which leads to a fundamentally dynamic view of form. At first I referred to process morphology as a more dynamic approach. Although correct, it does not sufficiently emphasize the fundamental difference between traditional dynamic morphology and a morphology in which process is considered fundamental. For this reason I prefer the term ‘process morphology’ that also reflects the connection to the process philosophy of Whitehead (1929), Nicholson and Dupré (2018), and others (see also Abraham (1986) and plant morphodynamics research that may or may not transcend the structure-process dualism).

I first introduced process morphology as “a dynamic multidimensional approach” in a study of the androecium (Sattler 1988). Then, still referring to it as “a more dynamic approach,” I articulated it as a general approach for the study of all plants. We investigated how it works in complex situations such as
Utricularia (Sattler and Rutishauser 1990). We used multivariate analysis to demonstrate quantitatively the dynamic continuum in vascular plants (Jeune and Sattler 1992). I discussed the significance of process morphology for developmental and evolutionary morphology (Sattler 1992). And finally I showed how process morphology can shed new light on the origin and evolution of land plants (Sattler 1998): process morphology allows a synthesis of two opposite views, the telome theory and Hagemann’s alternative theory according to which dorsiventral leaf-like structures gave rise to land plants.

A dynamic view of plant development has also been elaborated long ago by Schultz (1843), also called Schultz-Schultzenstein (1867), in his
theory of anaphytosis according to which plant development is envisaged as the processes of branching and articulation that lead to the formation of successive articles (anaphytes). I refer here only to the morphological aspects of this theory (that has also been referred to as the theory of anaphytes) because the physiological aspects have been largely surpassed by modern research. If we understand the morphological formation of anaphytes in terms of process combinations, we have a modern process-morphological version of the theory of anaphytosis. Thus, one anaphyte (a process combination) through branching gives rise to another one (another process combination), and so on. Branching here is not synonymous with the formation of a new shoot but more generally the formation of a new growth center (primordium), which may or may not form a new shoot (a branch in the classical sense). Obviously such a view transcends the strictures of structural categories since the emphasis is on process and process combinations. Nonetheless, certain branching patterns correspond to typical representatives of classical categories such as shoots or compound leaves, but others correspond to intermediate or aberrant forms that do not fit the classical categories. Thus, the whole diversity of plant form is included. As pointed out by Schultz-Schultzenstein (1867), this view goes beyond the constraints and limitations of Goethe’s Metamorphosis of Plants. It applies to all plants, including living and extinct algae, bryophytes, and vascular plants. In the case of unicellular organisms only one anaphyte is formed without branching. There are no misfits according to this view; everything fits because everything can be understood in terms of branching and articulation. Even the most bizarre structures that do not fit the classical categories such as those described in the Lentibulariaceae and Podostemaceae by Rutishauser (2016) can be understood in this way. Thus, these misfits need no longer be forced into one or the other category. Much violent morphology that often has led to animosities among plant morphologists can be avoided. In this sense the modern version of the theory of anaphytosis may be called peaceful morphology. We no longer need to debate and quarrel whether a misfit is a leaf or stem. However, those who for one reason or another cannot accept the theory of anaphytosis as a satisfactory solution, for them perspectivism can also lead to peaceful reconciliation and tolerance (see below).

Arber (1946, p. 77) pointed out that in his
Metamorphosis of Plants Goethe took the leaf as a given, as the basis of the whole diversity of lateral appendages, and therefore did not enquire about its origin (see also Minelli 2018, 6.1). In contrast, the theory of anaphytosis explains the origin of leaves through branching and articulation. Arber’s partial shoot theory recognizes leaves as partial shoots (Arber 1950).

The theory of anaphytosis also explains easily the morphology of flowers, stamens and carpels. According to this theory, stamens and carpels result from branching and articulation, whereby the articles (anaphytes) represent unique process combinations that are not found in the vegetative region. Thus the questions whether stamens and carpels are leaf homologes and whether the flower is a modified monaxial shoot are superseded. Although not referring to process morphology and the theory of anaphytosis, Claßen Bockhoff (2016) also went
beyond the classical interpretation of the flower when she concluded: “Flowers are sporangia bearing units rather than short shoots with floral organs.” These sporangia bearing units can be understood as branching systems with unique articles (process combinations).

Goethe’s view of nature was dynamic. In
Nature (A Fragment) he wrote: “She [nature] is eternal life, eternal becoming, eternal change, yet she does not move forward. She ever transforms herself, without pausing to rest” (translation by Mueller 1989, pp. 242-243). Goethe’s morphology appears dynamic as he emphasized “Bildung und Umbildung” (formation and transformation). However, in his Metamorphosis of Plants it is always the same organ that changes. The essence of that organ, the leaf, does not change. He emphasized the dynamic principles of contraction and expansion (Zusammenziehen und Ausdehnen), universal principles already recognized in Daoism as Yin and Yang. In a letter to Kanzler von Müller (1828) about his essay “Die Natur,” Goethe added the principles of polarity and enhancement (“Steigerung”), which I find were already implied in “Die Natur.” Like expansion and contraction, polarity (an expression of the process of polarization) is well recognized in modern morphology and biology, and in psychology. It may manifest as attraction and repulsion. Goethe also referred to “organische Entzweiung,” which literally means organic division into two (see Troll 1926, p. 235, Schilperoord 2011, pp. 148-151 ) and he emphasized unity. Arber (1967) referred to this as the coincidence of contraries. Goethe’s process of “Steigerung” may be translated as enhancement or progression and upward striving (Mueller 1989, p. 245). He extolled striving in Faust II:

Wer immer strebend sich bemüht
Den können wir erlösen.

(He who endeavours to strive,
We can redeem)

In contrast, Dilgo Khyentse Rinpoche (2005) said: “There should be no feeling of striving to reach some “amazing goal” or “advanced state.” To strive for such a state is a neurosis which only conditions us and serves to obstruct the free flow of Mind.”

With regard to plant development, Goethe recognized polarity (polarization) in embryogenesis when the first leaf, the cotyledon arises opposed to the root. In this context Goethe understood the leaf in the broad sense as a metamer that includes the node and internode below the lateral appendage. Hence the stem is included in the polarity of root and leaf in the broad sense. After the formation of the cotyledon or cotyledons, successive leaves expand in size and differentiation, but subsequently the bracts and sepals contract. Then the petals expand again, the stamens contract, and as the carpels form the fruit we witness the final expansion. Thus Goethe recognized six phases of expansion and contraction. He considered development from the cotyledons to the fruit progressive (“Steigerung”) because to him the fruit was the highest a plant could produce.

In his notebook during his Italian trip Goethe proposed the following hypothesis: “Alles is Blatt” (All is leaf), to which he added: “Und durch diese Einfachheit wird die grö
βte Mannigfaltigkeit möglich…Ein Blatt, das nur Feuchtigkeit unter der Erde einsaugt, nennen wir Wurzel… Ein Blatt, das sich gleich ausdehnt einen Stiel, Stengel” (quoted by Troll 1926, p. 52), which means that a leaf that shows radial growth is called a root or stem depending on its function. I consider this hypothesis highly significant because it transcends the essentialist view of mutually exclusive organ categories. Instead of the three fundamental organ categories (Troll’s three fundamental organs, the “Grundorgane”), here we have only one that depending on the operating process modalities such as symmetrisation can produce organs that we normally call roots, stems, or leaves. On this view, these organs are no longer fundamentally different, not essentially different; they are the expression of only one common structure, which Goethe called the “Blatt” (leaf), but which here has to be understood in a wider sense since it represents not only the lateral appendages but also the stem and the root. If this leaf in the wide sense (leaf sensu lato) is understood not as an essence but a fundamental process, as leafing, then Goethe’s hypothesis that all is leaf (meaning leafing) could be seen as a forerunner of process morphology. Schad (2005, p. 211) extended Goethe’s leaf sensu lato to mean “jedes potenzreiche Grundgewebe” (each ground tissue rich in potential). Accordingly, all structures of the plant kingdom, including those of algae, can be seen as leaves sensu lato (Schad, personal communication). If ‘tissue’ is understood in its original dynamic connotation meaning “to weave,’ then gound tissue rich in potential means a basic process (weaving) rich in potential. Such a view appears compatible with process morphology.

I have to add, however, a word of caution. Even in describing dynamic principles one might easily fall back into a structure-process dualism. It happens because of the noun-verb structure of our language: we need a noun (or pronoun) plus a verb to form a sentence (see, for example, Bortoft 1996, pp. 269-270). We say, for example: A leaf expands. Hence, we distinguish a structure (“the leaf”) and a process (“expansion”). In this way, the structure-process dualism seems to be built into our language structure. To overcome it in ordinary discourse we would need a language that is based on verbs only or where the noun also implies process (Sattler 1993). I have tried to develop such a language but apart from some rudimentary ideas, so far I have not had much success (see
Sattler: Special Interests, Sattler 2016, Chapter 7). But as has been suggested, instead of referring to a leaf, we could call it “leafing.” With regard to this leafing, Bockemühl (1966, 1967) referred to shooting, articulating (branching), spreading, and stemming according to Brady’s (1987, p. 281) translation. If applied to axial structures, there would be no spreading. Arber referred to “parallel becoming” (Arber 1950, p. 161).

Whorf (2012) claimed that some tribes of Amerindians have languages that are based primarily on verbs or only on verbs. A Hopi, for example, instead of saying “The sun shines,” would simply say, “shining.” Thus, there is simply the activity of shining, no agent that does the shining – hence a radically dynamic worldview. What I am suggesting is that we need the same in morphology.

Joshu Sasaki Roshi, a Japanese Zen master, would not refer to a pine tree, but to “the activity called a pine tree” (see Shinzen Young 2016, p. 129). “He talked this way to remind people that all the objects in the world [including the human self] can be experienced as waves of impermanence [dynamics], not just as concrete, separate things” (ibid, p. 129). Thus, the self is a fluid self, it “is not a noun, it is a
verb” (ibid, p. 159).

The Holistic Worldview (Organicism)

The holistic worldview, whose many versions may include the fuzzy worldview, may be considered a very comprehensive worldview, especially if it is understood in a dynamic way. In quantum physics David Bohm (1980, 1993) advocated a dynamic holism, which may be seen as an integration of contextualism (process philosophy) and holism. Bohm referred to “holomovement,” which means “undivided wholeness in flowing movement” (Bohm 1981, pp. 11, 151). As “holodynamics,” this view has been extended to include also the human dimension and psychotherapy (Woolf 1990). Thus, “the universe, all matter, energy, and intelligence are part of one, dynamic whole” (ibid, p. 196). Such encompassing holodynamics may integrate certain versions of Pepper’s world hypotheses (worldviews). My webpage on
Body, Speech, and Mind may be seen as an attempt in this direction. It remains a challenge for morphologists to develop a holodynamic morphology. In such morphology the plant would have to be seen as a dynamic whole integrated with its environment that includes animals and humans; in other words, as a dynamic soil-plant-air-animal and human-continuum (SPAAC) that also includes the continuum of the energy fields in and around the plant (see below and Sattler 2016, Chapter 2). Ultimately the plant will have to be seen as integrated into the the whole universe.

Goethe emphasized a holistic approach: “in living nature nothing happens that is not in connection with the whole” (Goethe, quoted by Holdrege 2014, p. 13). Herder, who met and influenced the young Goethe, saw nature and the universe as an infinite, organic unity. A plant then is considered an integral part of this infinite, organic unity. “Organic” implied “dynamic” and “spiritual,” spiritual not as opposed to matter but inherent in matter (see below in the section on animism). According to Thanissaro Bhikku (2015, p. 26), other Romantics such as Novalis, Schlegel, Schleiermacher, H
ölderlin, and Schelling shared this Romantic worldview, which also included the magical, mysterious, and sublime (ibid, p. 110). In as much it transcends language it also transcends science that seems to be limited due to its linguistic representation.

To some extent we may see a convergence between the Romantic worldview and holodynamic science, and also a convergence between the latter and certain religions such as Buddhism (see, for example, Capra 1975, McFarlane 2002, Luisi 2009, Capra and Luisi 2014). Some consider this convergence rather limited. But others see it as more profound. For example, in Buddhism the emphasis of impermanence (i.e., dynamics) and emptiness meaning boundlessness (i.e., interconnection) appears compatible with the holodynamic worldview in science.

Perspectivism and Complementarity

Perspectivism means that different positions constitute different perspectives on reality that complement one another. Even contradictory perspectives may be accepted as long as they are supported by facts. Evidently some perspectives may be much more comprehensive than others, but less comprehensive perspectives that illuminate other facets of reality may also be useful and important. With regard to morphology this means that all of the worldviews I included represent different perspectives on plant form that complement one another. I think that the fuzzy worldview and the dynamic and holistic worldviews provide the most profound and comprehensive perspectives, but I think that essentialism, in spite of its static limitations, has also made important contributions to our understanding of plant form and it works for the typical structures. Similarly mechanism, in spite of its limitations, has provided many important insights.

I need to recall that the plant is a continuous whole. Howard (1974) emphasized this with regard to the shoot when he referred to the “stem-node-leaf continuum.” This continuum has been dismembered conceptually in five different ways (Cusset 1982,
Rutishauser and Sattler 1985), which leads to five different models of the shoot:
1. the classical stem-and-leaf model,
2. the fertile-leaf model,
3. the leaf-skin model,
4. the phytonic model sensu stricto
5. the metameric model. (#4 and # 5 together have been referred to as the phytonic model sensu lato)
Adherents of these different models have often argued which model is the correct or appropriate one. Such arguments seem futile to a great extent. They are based on an either/or logic, meaning that any view is either correct or not. In the extreme this may lead to the stance represented in Hoggan’s book: “I’m right and you’re an idiot.” We can overcome this toxic attitude through both/and logic, which entails perspectivism and complementarity. Thus, the different models complement one another because they present different perspectives. This need not necessarily mean that all perspectives are equally comprehensive. One may be more comprehensive than another one, and in any particular case one may be more appropriate than another one.

As I pointed out already, Goethe embraced different and contradictory perspectives on plant morphology. Among the five perspectives on the shoot that Rutishauser and Sattler (1985) contrasted, Goethe embraced three in different contexts, namely the stem-and leaf model, the fertile-leaf model, and the metameric model. Furthermore, he accepted the basic notion of Agnes Arber’s partial-shoot theory of the leaf when he wrote: “When leaves divide, or rather when they advance from their original state to diversity, they are striving toward greater perfection, in the sense that each leaf has the intention of becoming a branch” (quoted by C. J. Engard in Mueller 1989, p. 10). In another statement Goethe considered compound leaves as “in reality branches, the buds of which cannot develop, since the common stalk is too frail” (Goethe, quoted by Arber 1946, p. 78). Already in his
Metamorphosis Plants (1990, section 20), he wrote that compound leaves "prefigure complete small branches" (Arber 1950, p. 73). With regard to the flower, he wrote: "The pistil, the receptacle, and the fruit all belong to the system of the eyes [i. e. branches]" (quoted by Cusset 1982, p. 27), which means that, as I pointed out above, the pistil is not just a lateral appendage or appendages, but the homologue of a branch or branches. In terms of postmodernism with its central concept of deconstruction, this means that with regard to the flower and compound leaves Goethe himself deconstructed the essentialism inherent in his Metamorphosis of Plants and that he could take different perspectives on plant morphology and see their complementarity. In a poetic form he expressed this with regard to the leaf of Gingko biloba:

“Fühlst du nicht an meinen Liedern,
β ich eins und doppelt bin?”
(Can’t you feel in my songs
that I am one and two?)

Goethe also recognized perspectivism and complementarity with regard to worldviews. Although he emphasized essentialism and phenomenology, he embraced all of the nine worldviews that I discuss in this article. Hence, Cusset’s (1982) reference to the “all-embracing Goethe” seems rather appropriate.

Nietzsche, who coined the term ‘perspectivism,’ also supported a perspectivistic philosophy. After Nietzsche, perspectivism has been taken up in postmodernism. And perspectivism has also ancient
roots. In ancient India it was evident in the logic of Buddhism and Jainism. Contrary to Aristotelian
either/or logic with only two values, Buddhist logic has four values: either, or, both/and, neither/nor.
Jain logic, also referred to as Anekant or Many-Sided Wisdom (Rankin 2010), has seven values. This
means that there are seven perspectives for each proposition:
in some ways it is
in some ways it is not
in some ways it is and it is not
in some ways it is and it is indescribable
in some ways it is not and it is indescribable
in some ways it is, it is not, and it is indescribable
in some ways it is indescribable

If we apply this logic to plant structures such as, for example, a phylloclade, we could conclude that 1. in some ways it is stem, 2. in some ways it is not a stem, some ways it is and it is not a stem, 4. in some ways it is a stem and indescribable, 5. in some ways it is not a stem and indescribable, 6. in some ways it is a stem, it is not a stem, and it is indescribable, and 7. in some ways it is indescribable.

Healing Thinking and Being (Sattler 2010), I showed how Buddhist and Jain logic as well as some modern forms of logic such as fuzzy logic can be healing because they allow us to overcome the antagonism, conflict, violence and war that Aristotelian either/or logic may engender. Note that these healing ways of thinking are not anti-Aristotelian. They include Aristotelian either/or logic and go far beyond it. My book Wholeness, Fragmentation, and the Unnamable (Sattler 2016) includes a perspectivistic outlook on the world, reality, the human condition and its transcendence. The neither/nor of Buddhist logic and the indescribable of Jain logic, although perspectives, also go beyond perspectivism because they contain all possible perspectives; in other words, perspectives arise within them, but they transcend all perspectives.

Think, for example, of a person with whom you have a difficult relationship and whom you tend to condemn. In terms of Jain logic, you may say (s)he is horrible, but (s)he is also not horrible, (s)he is indescribable (mysterious), etc. The same may be said for groups, organizations, and nations. Such an attitude may lead to a reenchantment of relationships and the world. Griffin (1988) enquired about the reenchantment of science. I think we should also enquire about a reenchantment of plant morphology, which has to begin with the thinking of plant morphologists and the inclusion of the following worldviews.

Other Worldviews

Pepper (1942/70) listed three other world hypotheses (worldviews): the generating-substance hypothesis, animism, and mysticism. He rejected them, but I think that, although not much attention has been paid to them in plant morphology, they present important additional perspectives that complement the predominant views on plant form. In a sense they may even go beyond philosophy and science to the source of existence.

The generating-substance hypothesis

According to Pepper, this hypothesis that originated with pre-Socratic philosophers was the first self-conscious world hypothesis in Europe. It posits one or more than one substances that generate the manifoldness of reality. For Thales this substance was water, for Anaximenes air, for Empedocles water, air, earth and fire, and for Anaximander “apeiron,” which has been translated as indefinite, boundless, and infinite. Although fundamentally apeiron is beyond perspectives, it generates opposites, which then give rise to everything else. One pair of opposites is genesis and decay, which also figure prominently in process morphology in the form of growth and decay. But whereas growth and decay as well as differentiation and dedifferentiation form the starting point of process morphology, Anaximander traces them back to apeiron. Thus ultimately the diversity of plant form can be seen as arising out of boundless infinity - what Korzybski (2010, p.19) referred to as the "un-speakable." I think that this view comes close to or even merges with some forms of animism and mysticism (see below). The generation of form out of one material substance such as water or air seems no longer tenable.

Goethe’s (1831) reference to the mysterious ground of everything (“den geheimnsissvollen Urgrund aller Dinge”) may be seen as pointing to apeiron. Whether the following verse also points to apeiron in not so clear:

Und es ist das ewig Eine
Das sich vielfach offenbart.
(And it is the eternal One
That manifests itself in many ways)

If the eternal One is equated with the mysterious ground of everything, then it may point to apeiron. If, however, it refers to an underlying type, an idea, or essence that manifests in many ways, then it is at best a derivative of apeiron. It seems that Troll interprets this verse in an essentialist way (Troll 1926, pp. 21 and 99).


According to this view, everything is animated. Being animated can have different meanings such as reference to a soul or spirit(s) and/or subtle energy fields extending from physical bodies. Recognizing that plants are not just material objects but endowed with spirit(s) leads to reverence, which requires a spiritual transformation or at least a change in attitude of the researcher. Recognizing subtle energy fields such as auras may require a change in the state of consciousness of the observer (see, for example, Steiner 1950, Greene 2009, Olwen 2017). Some people, including myself, can see auras. It seems that children often see auras because they may draw them, but they often lose this ability as they grow up in our predominantly materialistic culture. Those who cannot see auras understandably tend to be skeptical, but there is some scientific evidence for subtle energies (see, for example, Tiller 2007, Sattler 2016, Chapter 2).

Auras have significance for plant morphology because they show that plants do not have a sharp boundary where most people see it but extend into the environment. Although auras tend to be rather dynamic, different layers have been distinguished and different names have been used for these layers by different authors (see Sattler: Body, Speech and Mind). All of them are integrated into a universal energy field that can be seen as an aspects of beingness, no-thingness, and unity consciousness (Greene 2009) or spirit that encompasses matter (Wilber 2006, 2007).

Our state of consciousness influences our perception of the world, including the morphology of plants. And since our state of consciousness is not separate from what we observe, it has also a potential influence on whatever we observe such as humans, animals or plants. In other words, we do not only perceive what is around us, we also may influence its being. Thus, a loving person may have a different influence than a violent person and consequently may have a different perception. For example, a person to whom a plant or animal or human being is only a material mechanism influences and perceives them differently from a person who loves and reveres them (see also Shepard 1993, Sattler 2016, Chapters
6, 12).

For Spinoza God and nature were two different words for the same reality ("Deus sive natura"). Thus nature was divine, sacred to him. For Goethe, who was greatly influenced by Spinoza, nature was animated, loving, divine and mysterious. One of his poems is entitled “Weltseele” (world-soul); in another poem entitled “Eins und Alles” (One and All), he wrote:

Weltseele, komm, uns zu durchdringen!
Dann mit dem Weltgeist selbst zu ringen,
Wird unserer Kräfte Hochberuf.

(World-soul, come forth, within us nestle.
The world’s own spirit we shall wrestle –
This is our being’s highest thought)
(quoted from the translation in Magnus 1961, p. 183)

According to Steiner (2006), Goethe recognized the three realms of the physical, astral and spiritual in nature. With regard to spirit, Goethe wrote: “matter never exists without spirit, and spirit never without matter” (quoted in Mueller 1989, p. 245). Thus spirit is also in plants and their forms. Steiner (1910) referred to “the spirit in the realm of plants.”

Spirit is also used in the plural. So Faust says:

O gibt es Geister in der Luft,
Die zwischen Erd und Himmel herrschend weben,
So steiget nieder aus dem goldenen Duft,
Und führt mich weg zu neuem bunten Leben!

(if there be spirits of the air, that float and rule between the earth and sky, descend I beg you from the golden vapors, and sweep me forth to rainbow-colored life)

Instead of invoking a soul or spirit(s), Portmann (1956, 1965) referred to “Innerlichkeit” (interiority) that manifests in the “Selbstdarstellung” (self-presentation) of the organism. This “Innerlichkeit” (interiority) appears as a great mystery, “das grosse Geheimnis” (Portmann 1965, p. 244), which relates it to mysticism.


Although mysticism may be seen as a worldview, I would rather characterize it as the
awareness of the unity of the whole universe that transcends all concepts and boundaries, including space and time, name and form (idea, essence). Since change (dynamics) requires time, in timelessness change (dynamics) is also transcended. Hence, as stated in the Heart Sutra, dharmas (meaning things or phenomena) "are neither produced, nor destroyed" (Thich Nhat Hanh 1988, p. 19) because production and destruction requires time. In other words, "no Birth, no Death."

From this perspective, form, including plant form, appears boundless in space and time. As it is said in the Heart Sutra:

“Form is boundlessness,
Boundlessness is form”
(Tanahashi’s (2014) translation)

This sutra provides the most inclusive view of form, including plant form: form is boundless, thus unnamable and mysterious, and yet it can also be described in its bounded manifold manifestations. According to the Heart Sutra and nondualism in general the boundless, unnamable, mysterious and the bounded manifold manifestations that we perceive as distinct forms are one (not two, not dual). This insight leads to the most profound mystery or mysteries, which in some translations of the first chapter of the Tao Te Ching sometimes is referred to as darkness or even the darkest of darkness:

Therefore ever without desire we contemplate the mystery,
ever with desire we contemplate its boundaries.
These two arise together, but have different names.
Together we call them dark, the darkest of the dark,
the door of all mysteries.
(Tao Te Ching, Chapter 1, translated by S. A. Sabbadini 2013)

In my latest book
Wholeness, Fragmentation, and the Unnamable: Holism, Materialism, and Mysticism – A Mandala (Sattler 2016), I used a mandala to integrate the unnamable in the center of mandala and the namable (wholeness and fragmentation radiating from the center) in a nondualistic way as indicated in the Heart Sutra and the Tao Te Ching. I think that Goethe also alluded to this integration when he referred to the mysterious ground of everything (“den geheimnisvollen Urgrund aller Dinge”) and the first verse of his poem Epirrhema might also be interpreted in this way:

Müsset im Naturbetrachten
Immer eins wie alles achten:
Nichts ist drinnen, nichts ist draußen,
Denn was innen, das ist außen.
So ergreifet ohne Säumnis
Heilig öffentlich Geheimnis

(In contemplating Nature’s being
Know the One as many, seeing
In and outer coinciding,
Nothing in from out dividing
Open secret, relevation!
Grasp it without hesitation.)
(translation by Aldyth Morris)


Looking back at Pepper’s seven worldviews, we can see that essentialism and mechanism, although in one way very different, have in common that they fragment the world in terms of entities and categories. In contrast, the other five worldviews emphasize wholeness: contextualism (the dynamic worldview) and holism may be even subsumed under a holodynamic worldview; Anaximander’s generating-substance hypothesis and mysticism point to the unnamable, and animism can be understood in different ways most of which imply wholeness and holiness. Perspectivism seems all-inclusive as it acknowledges the different worldviews as different perspectives on reality. The Yin-Yang symbol of Daoism may illustrate these perspectives:

Yin and Yang

Yin (represented by the black area) and Yang (the white) represent two aspects of the all-encompassing Dao (the circle as a whole). If we look only at the black versus the white area, it represents Aristotelian either/or logic that characterizes categorical thinking. It refers to oppositions such as stem versus leaf or stem versus root. As I pointed out, such either/or oppositions have some limited validity. Depending on the situation, they may lead to insight. However, if we include the black in the white and vice versa, we recognize both/and logic, the logic of perspectivism and complementarity. And since Yin and Yang can be present to different degrees as they flow into each other, continuity (fuzziness) and fuzzy logic are symbolized. Furthermore, since in the Yin-Yang symbol it is implied that Yin and Yang are not static but become transformed into one another as night and day flow into each other, the symbol also represents dynamics, dynamics that is molded by the two fundamental forces of contraction (Yin) and expansion (Yang). Finally, since the circle that encloses Yin and Yang is not separate from them, this unity points to the nondualism of the unnamable whole (the Dao) and its manifestations, the deepest mystery that may have been recognized by some of the greatest scientists:

“The most beautiful and deepest experience a man [and woman] can have is the sense of the mysterious. It is the underlying principle of religion as well as of all serious endeavor in art and in science” (Albert Einstein 1932).

“[Therefore] let us regard this universe, all of its life and evolution, and the evolution of human culture and the human mind with awe and wonder” (Stuart Kauffman 2008, p. 232).

Goethe also appreciated and revered the mysterious (“das Unbeschreibliche,” “das Unbegreifliche,” “das Geheimnis,” quoted in Troll 1926, pp. 2 and 107). And I think one can also find the other aspects of the Yin-Yang symbol in Goethe’s morphological writings. Although he emphasized identity, essential similarity or sameness, he also recognized a dynamic continuum molded by contraction and expansion, the two basic forces represented by Yin and Yang. He acknowledged different, even contradictory perspectives and their complementarity. And through the nondualistic unity of the particular and the unnamable whole he revered the mysterious source of everything, “den geheimnisvollen Urgrund aller Dinge” (Goethe 1831).

His encompassing view of an organism was "to divide, to unite, to merge into the universal, to abide in the particular, to transform itself, to define itself, and, as living things tend to appear under a thousand conditions, to arise and vanish, to solidify and melt, to freeze and flow, to expand and contract. Since these effects occur together, any or all may occur at the same moment. Genesis and decay, creation and destruction, birth and death, joy and pain, all are interwoven with equal effect on weight; thus even the most isolated event always presents itself as an image and metaphor for the most universal" (see Bell 2016).

Characterizing Goethe only as a phenomenologist and his method only or mainly as intuitive judgement (anschauende Urteilskraft), as it has been done so often, appears rather incomplete, one-sided, misleading, and a disservice to the “all-embracing Goethe” (Cusset 1982). Although he wrote a short essay on intuitive judgement, subsequently he became very critical of it and concluded that, "the duel between the perceived and the ideated remains forever unresolved" and that art, not science, is nature's "most worthy interpreter." With regard to philosophers, we can find in Goethe ideas expressed by Anaximander, Heraclitus, Plato, Aristotle, Spinoza, the German Romantics, Kant, Hegel, Husserl, Nietzsche, Whitehead, Wittgenstein, Kosko, and others. And besides philosophical ideas we can also find the wisdom and silence of mystics when he concluded:

“Das schönste Glück des denkenden Menschen ist, das Erforschliche erforscht zu haben und das Unerforschliche ruhig zu verehren”
(Goethe, quoted in Troll 1926, p. 2).
(The most beautiful happiness of a thinking person is to have researched that which can be investigated and to revere in silence that which is beyond investigation)


I want to thank Alessandro Minelli and Rolf Rutishauser for valuable comments and suggestions.


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See also Plant Morphology, The Evolution of my Phytomorphological Research in my Publications and Plant Evo-Devo (Evolutionary Developmental Biology), Morphological Development (Organogenesis) of Flowers, From Plant Morphology to Infinite Issues (including Ken Wilber and Korzybski) and Science: its Power and Limitations

Latest update of this webpage on July 25, 2022.