Raymond L Weiss. The Review of Metaphysics. Volume 61, Issue 1. September 2007.
Darwin was not a philosopher. He can be fairly called a “philosophical naturalist,” an expression that he favors when referring to the most thoughtful of his colleagues. But insofar as his thoughtis grounded in the philosophic tradition, Darwin deals with the permanent problems of philosophy. His thought in fact has a certain Greek lineage, despite the obvious and important differences from the Greeks.
But were not the problems that preoccupied Darwin characteristically modern, dependent upon an attitude fostered by the new science along with fossil discoveries, advances in geology, and so on; did not the”species problem” come to the fore owing to factors associated with modernity? Darwin’s focus upon forms of life, however, places him squarely within an ancient philosophic tradition. The Origin purports to be a rational account of forms.
The following objection can be made here. Evolutionary theory depends upon the modern notion of “history,” which has no place in Aristotelian philosophy; nature, rather than “history,” is fundamental for Aristotle. But when Darwin speaks of the “history of the organic world,” he refers to the forms that have undergone change in a meaningful sequence over long periods of time. Although the passage of great periods of time is, of course, crucial to the Darwinian position, history is not strictly a causal agent for Darwin. It is nature, rather than history, that produces new forms; hence, he can speak meaningfully ofnatural selection. It is difficult to say whether “history” actually exists for Darwin. He apparently uses the term as a conceptual thread unifying the development of forms over time, while remaining an heir tothe Aristotelian position regarding the centrality of what exists by nature.
Darwin’s forms come into being and pass way; they lack the permanence of Aristotelian forms. But the Greek echo in Darwin’s view of forms—be they “species” or ‘Varieties”—is evident in his understanding of the whole and its parts. Consider, for instance what he says in the massive book that he had been working on prior to composing the Origin. When introducing natural selection, he underscores the need to explain “the infinitude of exquisitely correlated structures,” such as the anteater, “with its great claws and wonderful tongue.” He then goes on to say that “the most credulous believer in the ‘fortuitous concourse of atoms’ will surely be baffled when he thinks of those innumerable & complicated yet manifest correlations”—those amazing structures found everywhere in the organic world. Darwin, so to speak, takes the side of Aristotle against Democritus. Nature is not ruled by chance (the “fortuitous concourse of atoms”). Purposiveness is evident from the ordered relation of parts to one another and to the requirements of the whole organism.
Darwin regards forms as inherently variable; hence, they are able to change in such drastic ways over large periods of time. As is well known, Darwin denies that there are any “natures” or “essences.” It is noteworthy, though, that no matter what changes take place, there will always be forms. The ongoing existence of forms does not depend upon the usage of naturalists or the conventions of language. Forms exist not by convention but by nature.
The source of particular forms is the struggle for existence, which itself exists by nature. But what is the source of forms altogether? Why are there any (organic) forms at all? Darwin does not know. What he does understand is the principle of their change, that is, the origin of species. There is a limit to the questions that he is disposed to ask, a limit that is set by his understanding of the task of a natural scientist.Darwin operates within a Baconian context in which natural philosophy is restricted to what is knowable by means of Baconian methodology, that is, through gathering together and observing particulars. We might nonetheless wonder whether Darwin’s ignorance of the origin of (organic) forms is not a severe handicap. For according to Darwin, to know what “X” is, the genesis of the thing must be known. If he does not have knowledge of the genesis of (organic) forms, he does not know what an (organic) form is. And if he does not know what an (organic) form is, he is not in a position to give a comprehensive or fully adequate account of the origin of species (namely, living forms).
Darwin was well aware that his ignorance of life’s origin could induce doubts about the soundness of natural selection. The matter comes up, for instance, in his correspondence with the German paleontologist H. G. Bronn. Darwin writes: “Lastly, permit me to add that I cannot see the force of your objection, that nothing is effected until the origin of life is explained: surely it is worth while to attempt to follow out the action of electricity, though we know not what electricity is.” Darwin is thus in the same position as the physicist who lacks knowledge of what electricity is. Darwin gladly concedes his ignorance. But one can presumably understand the effects of “X” without knowledge of what “X” is. Such knowledge is emphatically provisional, which Darwin in a way grants by speaking of his theory of natural selection as a “hypothesis.”
In any event, the subject matter of Darwin’s inquiry are forms whose organic character is manifest in having parts that (to use Aristotelian language) are “instruments” hierarchically ordered toward the end of survival. That the form has a teleological structure is quite evident. Darwin’s son Francis underscores the significance of teleology for his father’s work—which, according to Francis Darwin, revived the study of purposiveness in organisms. “[T]he evolutionist studies the purpose or meaning of organs with the zeal of the older Teleology, but with far wider and more coherent purpose.” Although this statement has all the trappings of hyperbole, evolutionary theory does indeed deal with problems that could not be handled, or at any rate were not handled, by the older teleology.
For example, how can the Aristotelian final cause account for divergent characteristics within the same species? This very difficulty was raised by a leading medieval Aristotelian, namely, Maimonides, who notes that the final end is unable to explain why, for instance, some ants have wings while others do not. Darwinian natural selection has an explanation for such phenomena, but it does not account for the coherence and purposefulness of an organism’s parts. The Aristotelian final end, which in living beings is the same as the form, does just that. But then, it does not explain the origin of new species, nor can it account for the development of higher forms of life. This is the well-known charge leveled against Aristotelian natural philosophy by Darwinians.
Darwin’s forms must have a certain stability to be knowable, that is, identifiable as members of a particular species. Is the relative permanence of “species,” taken for granted in the Origin, explicable on Darwinian grounds?
This very difficulty was raised early on by the eminent paleontologist, Hugh Falconer, a friend and colleague of Darwin. In an 1863 article Falconer applied the Darwinian thesis regarding species to the question of whether the mammoth and other extinct elephants could have emerged suddenly. He expresses support of Darwin: “The most rational view seems to be, that they are in some shape the modified descendants of earlier progenitors.” But he goes on to say that when one considers “the geometrical law governing the evolution of form”—as found, for example, in the development of spiral shells—”it is difficult to believe that there is not in nature, a deeper seated and innate principle, to the operation of which ‘Natural Selection’ is merely an adjunct.” Especially telling is the survival of the mammoth’s structure in widely different climates and times. “If species are so unstable, and so susceptible of mutation … why does that extinct form stand out so signally a monument of stability.”
Falconer suggests that a mathematical basis of organic patterns is needed to supplement and deepen natural selection. Besides spiral shells that disclose a geometric patterning, he refers to the “law of Phyllotaxis” that governs the development of leaves around the axis of a plant; each such instance is a “term of some series of continued fractions.” Falconer refers here to the Fibonacci sequence that Goethe had treated as so important for understanding plants. The persistence of geometrical proportion is not explicable by the struggle for survival; it is part of the evidence of the organic form’s stability that had been glossed over by Darwin.
For Darwin, however, the “mysterious” laws of growth are germane to explaining the recurrence of certain patterns in a given species. About the wonderful patterns in unicellular algae he says: “I should attribute most of such structures to quite unknown laws of growth”; he adds that “mere repetition of parts is to our eyes one main element of beauty.” By regarding such structures as dependent upon the laws of growth, Darwin in effect agrees with Falconer that the cause of the pattern is distinct from natural selection. Falconer, though, goes further by suggesting that a geometric law is at work, a law that is indicative of something more fundamental, as yet unknown, in nature.
From Darwin’s viewpoint, there is no need to assume anything more basic in nature than natural selection to explain the development of new species. The causal power of natural selection is the fundamental phenomenon; geometric patterning is a means to the end of survival. Different sorts of patterns can be integrated into the form so that it is suitably adapted. Whether geometry ought to be regarded as somehow more fundamental than the organic form, that is, whether recourse must be had ultimately to Plato, is a problem that extends beyond the purview of this paper and, indeed beyond our present-day knowledge: we are ignorant of the fundamental principles of things.
In any case, there is no basis for the form’s stability in Darwin’s account of evolution, and this poses difficulties for his position. One such difficulty is whether the individual, that is, a particular, is knowable.The problem can be formulated in classical terms as follows: if a thing has no essence (or nature), there is no universal on the basis of which it can be comprehended. For Darwin’s thought, the problem is connected with the almost infinite malleability of forms over time (with the well known restrictions concerning what is possible at any given time). His solution is to seek a genealogical account of the individual: what the organism is (a woodpecker, and so forth) is thought to be knowable through studying its genealogical heritage. But any stopping point in this quest for knowledge is arbitrary. For knowledge of a given species requires knowing not only its immediate ancestors but also the more remote ancestors ad infinitum. It would not be enough, say, to know whether a dog descends from a wolf or jackal but one would have to investigate as well the ancestry of the wolf or jackal, and so on. François Jacob has sharply delineated the meaning of “origin” in an evolutionary context: “Origin becomes the vanishing point of history, the necessary zone of convergence where all the rough outlines of organization meet, where all divergences, disparities, and differences disappear.”
Of course, this whole approach to the natural world, and thus to the individual, differs from the Aristotelian view of the finality present in natural entities. “Nature avoids what is infinite, because the infinite lacks completion and finality, whereas this is what nature always seeks.” Moreover, knowledge, for Aristotle, requires the presence of boundaries or limits, which are imposed by definable forms.
We have reached an impasse. On the one hand, Darwin implies that there is no knowledge of individuals; the difficulty is transparent because he also implies that there are only individuals. Aristotle, on the other hand, does not account for the generation of new and higher forms of life. From any point of view, we need a more comprehensive understanding of forms and their source. But this is lacking at the present time.
Darwin and Aristotle operate, finally, on the basis of different premises. This is not to deny that Darwin’s position has a certain affinity with that of Aristotle: both take their bearings initially from the so called common sense world. But Darwin, as a modern scientist working mainly with Baconian premises, has considerably transformed the Aristotelian view. The form, for Darwin, is not a causal agent; it is, rather, the product of material processes (although he does not speak openly as a materialist). Darwin thus follows in the footsteps of the father of modern scientific empiricism, namely, Francis Bacon, who radicalizes the older view by contending that the new science will understand matter as determinative of form. He regards the break with premodern thought on this issue as a break with Plato, who “lost the real fruit of his opinion, by considering of forms as absolutely abstracted from matter, and not confined and determined by matter.” Bacon’s opposition to Plato is also, of course, an opposition to Aristotle.The new science was indeed established on an anti-Aristotelian foundation.
Having denied the existence of Aristotelian forms, Bacon was confronted with the problem of how knowledge of natural things is possible. His solution was that knowledge of how things come into being, the so called efficient cause, is all that is needed to conquer nature for the benefit of humankind. “Of all signs there is none more certain or more noble than that taken from fruits (ex fructibus). For fruits and works are as it were sponsors and sureties of the truth of philosophies.” This might be well and good for the modern scientist (if Bacon is right), but it surely does not help Darwin. He does not have in view a practical sort of knowledge; his aim is to advance a strictly theoretical understanding of organisms. As for whether his knowledge would assist breeders—he learned from breeders; he did not expect to benefit them.
It is, then, already problematic for Bacon whether knowledge of things in themselves is possible, for knowledge ex fructibus is not as such certain (although there is none “more certain” than this). Darwin, so to speak, inherits the cognitive difficulty. He himself speaks of natural selection as a “hypothesis” that he has “invented”; it is the hypothesis that is knowable, not the things themselves. How the new forms of life are generated is, however, knowable through the law of natural selection.
To clarify where we stand today, a few brief comments regarding the conflict between the Darwinian and the Aristotelian teachings are in order.
(1) Aristotle lays the foundation for his study of living beings in the De Anima with an account of soul, which is the source of life. His understanding of form is indispensable for this purpose, the principle of life being identified as the form of a natural body that is potentially alive. Further Aristotelian inquiry, in various other works, elucidates what it means for different kinds of beings to be alive. Darwin, however, focuses to a considerable extent upon species that are no longer alive, taking full account of fossil evidence. Evolutionary theory attempts to explain inter alia how species become extinct. History thus plays an important role in the Darwinian scheme of things, even though it is nature that produces new species.
In his study of living beings, Darwin makes no attempt to give a scientific account of the difference between the living and the nonliving. He simply takes for granted what is knowable to “common sense.” In a rare instance in which he tries to give a clear-cut account of what distinguishes the living from the nonliving, his common sense orientation is evident: “The most humble organism is something much higher than the inorganic dust under our feet; and no one with an unbiased mind can study any living creature, however humble, without being struck with enthusiasm at its marvelous structure and properties.” His common sense judgment, marked as it is by enthusiasm, is informed by the sensibility of a naturalist.
2) For Aristotle, potentiality is basic to understanding living beings: their growth to full maturity actualizes a potential present in the particular form and its concomitant matter. Potentiality presupposes the confluence of form and matter—a conceptualization that makes no sense in Darwin’s scheme of things. He does not differentiate form and matter; he speaks only of “forms”—which are understood to be bodily entities. And basic to his whole argument is the denial that new forms are “potentially” present in their predecessors. “There is no innate or necessary tendency in each being to its own advancement in the scale of organization.” It is the Hobbesian struggle for survival that leads to the success of “favored species.” Concerning climbing plants, for instance, Darwin says: they “acquire and display this power [of movement] only when it is of some advantage to them.” No natural tendency impels them to become climbing plants rather than something else. Natural selection clearly conflicts with the Aristotelian view of the “power” present in a given organism directing it toward a preordained end. It is doubtful, however, whether Darwin can consistently exclude a conception of potentiality from his general view of living beings. What of his understanding of seeds? Darwin himself says: “The power in seeds of retaining their vitality when buried in damp soil may well be an element in preserving the species, and therefore seeds may be specially endowed with this capacity.”
(3) Lying just beneath the surface of the conflict between Aristotle and Darwin is the old quarrel between the ancients and moderns. The Hobbesian struggle for survival (as appropriated by Darwin) conflicts with the Aristotelian understanding of living beings. Insofar as Darwin retains certain Aristotelian components, they have been transformed so as to comport with what we may call the “biological Hobbes.”
In contradistinction to the Greeks, Darwin does not regard the forms as inherently intelligible; the rationality of his science is not grounded upon the things themselves. Darwin does, however, perpetuate in his own manner the old Greek view that to be is to have form (or to be informed). Darwin’s work represents a late stage in the ancient struggle to comprehend living beings in terms of form.