But if we cannot yet fathom meristic variation, at least we may infer that inheritance must be vibratory, not particulate. Ironically, then, Bateson commits his greatest error in thinking about his favorite phenomenon — for he never suspected the integrating theme that particles might code for substances controlling rates of processes:
When however we pass from the substantive to the meristic characters, the conception that the character depends on the possession by the germ of a particle of a specific material becomes even less plausible. Hardly by any effort of imagination can we see any way by which the division of the vertebral column into x segments or into y segments, or of a Medusa into four segments or into six, can be determined by the possession or by the want of a material particle. The distinction must surely be of a different order. If we are to look for a physical analogy at all we should rather be led to suppose that these differences in segmental numbers correspond with changes in the amplitude or number of dividing waves than with any change in the substance or material divided (1913, p. 35). [Page 411]
In a statement reminiscent of D'Arcy Thompson (see p. 1179), Bateson expresses his hopes for mathematical analysis in morphology:
It is in the geometrical phenomena of life that the most hopeful field for the introduction of mathematics will be found. If anyone will compare one of our animal patterns, say that of a zebra's hide, with patterns known to be of a purely mechanical production, he will need no argument to convince him that there must be an essential similarity between the processes by which the two kinds of patterns were made . . . Patterns mechanically produced are of many and very diverse kinds. One of the most familiar examples, and one presenting some especially striking analogies to organic patterns, is that provided by the ripples of a mackerel sky, or those made in a flat sandy beach by the wind or the ebbing tide. With a little research we can find among the ripple marks, and in other patterns produced by simple physical means, the closest parallels to all the phenomena of striping as we see them in our animals . . . We cannot tell what in the zebra corresponds to the wind or the flow of the current, but we can perceive that in the distribution of the pigments... a rhythmical disturbance has been set up which has produced the pattern we see; and I think we are entitled to the inference that in the formation of patterns in animals and plants mechanical forces are operating which ought to be, and will prove to be, capable of mathematical analysis (1913, p. 36).
Though Bateson never found his underlying vibrations, his faith in their existence as bearers of heredity fueled his primary anti-Darwinian argument for discontinuous variation, and consequent evolution by internally generated saltation:
When the essential analogy between these various classes of phenomena is perceived, no one will be astonished at, or reluctant to admit, the reality of discontinuity in variation, and if we are as far as ever from knowing the actual causation of pattern we ought not to feel surprised that it may arise suddenly or be suddenly modified in descent. Biologists have felt it easier to conceive the evolution of a striped animal like a zebra from a self colored type like a horse ... as a process involving many intergradational steps; but so far as the pattern is concerned, the change may have been decided by a single event, just as the multitudinous and ordered rippling of a beach may be created or obliterated at one tide (1913, pp. 36-37).
Bateson remained obstinate, and no closer to a solution, as the chromosomal theory became a foundation of modern biology. In 1924, he wrote to the great mathematician G. H. Hardy: “We have had some absurd attempts — mostly from biometricians — to apply mathematics to biology, but as I said my hope is still that I may live to see mathematics applied to biology properly. The most promising place for a beginning, I believe, is the mechanism of pattern.” [Page 412]
Bateson became more despondent about evolutionary theory in his later years, while remaining as stubborn as ever about his personal certainties. He visited Canada in 1922, and delivered a famous address entitled “Evolutionary faith and modern doubts” to the annual meeting of the American Association for the Advancement of Science. These were not happy times of consensus for evolutionary theory in general, but Bateson promulgated a particularly bleak vision, clearly colored by the failure of his personal hopes for a vibratory theory of heredity. He lamented that his closing plea of 1894, for integration of lab and field, had been thwarted thus far: “I had expected that genetics would provide at once common ground for the systematist and the laboratory worker. This hope has been disappointed. Each still keeps apart. Systematic literature grows precisely as if the genetical discoveries had never been made and the geneticists more and more withdraw each into his special 'claim' — a most lamentable result. Both are to blame . . . The separation between the laboratory men and the systematists already imperils the work, I might almost say the sanity, of both” (1922, in 1928, p. 397).
Bateson then issued his famous pronouncement — one of the most widely repeated lines in the history of evolutionary writing: “Less and less was heard about evolution in genetical circles, and now the topic is dropped. When students of other sciences ask us what is now currently believed about the origin of species we have no clear answer to give. Faith has given place to agnosticism” (1922, in 1928, p. 391).
Bateson did not fully understand the political and distinctively American context in which he had uttered these lines — the early days of agitation by William Jennings Bryan and the creationist movement for the first wave of anti-evolution laws that culminated in the Scopes Trial of 1925. Creationists seized upon Bateson's words, with their favored and unvarying tactic (still continuing today!) of willful distortion for rhetorical effect. What! A world's leading expert, British no less, from Darwin's own land, claiming to be (dare the word be uttered) agnostic about evolution! Bateson, appalled and angered, spent much time writing letters and articles to stress the point that we must still emphasize today against the rhetoric and similar distortions of modern creationists: theoretical doubt and debate do not alter the factual status of a subject; the fact of evolution and the theory of natural selection do not build the indivisible Eng and Chang of natural history, but rather specify claims of a different order.
But if Bateson became suffused with doubt about evolutionary mechanisms, he never wavered in his conviction that functionalist accounts in general, and Darwinian gradualism in particular, must rank as subsidiary and peripheral to a more valid formalism. Characteristically (for he never shunned controversy), Bateson chose the occasion of Darwin's most important centenary celebration — at Cambridge University in 1909 — to present his strongest critique of adaptation from a formalist perspective. He begins — using a favored physical analogy — with the venerable and standard critique of creativity: natural selection, as a negative force, can make nothing, but can only choose among variants produced by another process: [Page 413]
To begin with, we must relegate selection to its proper place. Selection permits the viable to continue and decides that the nonviable shall perish; just as the temperature of our atmosphere decides that no liquid carbon shall be found on the face of the earth: but we do not suppose that the form of the diamond has been gradually achieved by a process of selection. So again, as the course of descent branches in the successive generations, selection determines along which branch evolution shall proceed, but it does not decide what novelties that branch shall bring forth (1909, p. 96).
In a briefer epitome, Bateson had previously written (1904, in 1928, p. 238): “Selection is a true phenomenon; but its function is to select, not to create.”
Bateson then launches a two-pronged attack. In a first methodological critique, bordering on meanness (despite his cogent point), Bateson inverts Darwin's intent in proposing small-scale, continuous, isotropic variability as the source of evolutionary change. Darwin used this claim as a brilliant ploy for tractability in a context of ignorance about the nature of variation (see pp. 141–146) — for the assumption of isotr
opy allowed variation to play the role of supplying “raw material” only, thus permitting the search for mechanisms of evolutionary change to proceed notwithstanding. (An insistence that knowledge of the mechanisms of variation must underlie any explanation of phyletic change would have stymied the development of evolutionary theory and practice, for Darwin's world knew effectively nothing about the causes of variation, and possessed no techniques for obtaining the requisite information.) But for Bateson, the Darwinian claim of isotropy could only impede the development of a proper theory — for Bateson believed that the causes of change lay in variation, and an appeal to look elsewhere must therefore foreclose progress. Moreover, the Darwinian's favored “elsewhere” too often encouraged sterile exercises in adaptational guesswork, rather than a rigorous approach to assessing utility. Making an analogy to his favorite work of Voltaire (see p. 397), Bateson wrote:
While it could be said that species arise by an insensible and imperceptible process of variation, there was clearly no use in tiring ourselves by trying to perceive that process. This labor saving counsel found great favor. All that had to be done to develop evolution theory was to discover the good in everything, a task which, in the complete absence of any control or test whereby to check the truth of the discovery, is not very onerous. The doctrine “que tout est au mieux” [that all is for the best — the Leibnizian line that Voltaire places in the mouth of Dr. Pangloss] was therefore preached with fresh vigor, and examples of that illuminating principle were discovered with a facility that Pangloss himself might have envied, till at last even the spectators wearied of such dazzling performances (1909, pp. 99-100).
In a second substantive critique, Bateson sought to limit the domain of natural selection — a standard tactic based upon an argument of relative frequency. [Page 414] He had already extirpated the heart of Darwinian importance by labeling selection as a negative force. He now sought a further restriction by shrinking the frequency of selection's application even further. Many creatures may not be so well adapted as tradition dictates; natural selection need not always be working (“daily and hourly scrutinizing” in Darwin's words, 1859, p. 84), or, if working, not necessarily operating with substantial power: “May not our present ideas of the universality and precision of adaptation be greatly exaggerated? The fit of organism to its environment is not after all so very close — a proposition unwelcome perhaps, but one which could be illustrated by very copious evidence. Natural selection is stern, but she has her tolerant moods” (1909, p. 100).
Moreover, many structures usually regarded as direct adaptations may originate as sequelae or side-consequences of other changes (“spandrels” in my terminology — Chapter 11, and Gould and Lewontin, 1979). Organic integration, indissoluble by selection, may represent a more important morphological phenomenon than selective scrutiny part by part: “I feel quite sure that we shall be rightly interpreting the facts of nature if we cease to expect to find purposefulness wherever we meet with definite structures or patterns. Such things are, as often as not, I suspect rather of the nature of toolmarks, mere incidents of manufacture, benefiting their possessor not more than the wire-marks in a sheet of paper, or the ribbing on the bottom of an oriental plate renders those objects more attractive in our eyes” (1909, pp. 100-101).
I have presented this exegesis of Bateson in such detail because he so explicitly presented the formalist viewpoint as a direct alternative to Darwinism. His own style emphasized the facet-flipping (or saltational) theme of Galton's polyhedron, but he understood the place of directional variation in the general argument, and he expressed support for the second theme of orthogenesis with a conventional formalist emphasis on predictability and internally generated order, writing for example (1924, in 1928, p. 407): “What we have learned of variation, especially of the incidents of parallel variations, has taught us that many varietal forms owe their origin to a process of unpacking a definite pre-existing complex, with the consequence that, given the series of varieties to which one species is liable, successful predictions may sometimes be made as to the terms which will be found in allied series . . . These symptoms of order and variation have prepared our minds, and there may well be a sense in which orthogenesis will be found to denote a valid principle.”
Bateson therefore defended the purest example I know, among major 20th century thinkers, of a conscious and fully developed formalist philosophy harnessed to an explicitly anti-Darwinian theory. His formulation demonstrates that the dichotomy between structuralist and functionalist thought, the conceptual basis and primary theme of this chapter, cannot be regarded as an idiosyncratic or artificial device of rhetoric or textual organization, but rather denotes a widely perceived antithesis between two coherent world-views about nature.
In Problems of Genetics, Bateson lays out the dichotomy most clearly, even using the terms “external” and “innate” to contrast the Darwinian functionalism [Page 415] that he rejects with his own favored structuralism. This remarkable passage encapsulates the tradition of argument by relative frequency in natural history. Bateson acknowledges that natural selection occurs, of course, but relegates Darwin's force to a periphery of unimportance as an arbiter among novelties generated internally. Bateson manages, in this single passage, to attribute both stability and variation to internal causes, and to brand selection as a secondary tinkerer upon patterns established thereby:
We may ascribe the difference either to causes external to the organisms, primarily, that is to say, to a difference in the exigencies of adaptation under natural selection; or on the other hand, we may conceive the difference as due to innate distinctions in the chemical and physiological constitutions of the fixed and the variable respectively. There is truth undoubtedly in both conceptions. If the mole were physiologically incapable of producing an albino, that variety would not have come into being, and if the albino were totally incapable of getting its living it would not be able to hold its own ... I incline to the view that the variability of polymorphic forms should be regarded rather as a thing tolerated than as an element contributing directly to their chances of life; and on the other hand, that the fixity of the monomorphic forms should be looked upon not so much as a proof that natural selection controls them with a greater stringency, but rather as evidence of a natural and intrinsic stability of chemical constitution (1913, p. 28).
Bateson presents an even more striking contrast in later passages of the same book, when he develops an image for a great, if undoable, thought experiment — the perfectly controlled account of evolution under uniform conditions, unbuffeted by any of the Darwinian externalities that make real results so untidy and unpredictable: “No one disputes that the adaptation of organisms to their surroundings is one of the great problems of nature, but it is not the primary problem of descent. Moreover, until the normal and undisturbed course of descent under uniform conditions is ascertained with some exactness, it is useless to attempt a survey of the consequences of external interference” (1913, p. 187).
I am somehow stunned by this structuralist audacity in branding the functionalist panoply as mere “external interference” — and of imagining a formalist internal order so set and predictable that pathways of evolution might become as regular and predictable as planetary orbits, if only we could remove all these pesky environmental influences. The impetus and sine qua non of change for Darwin becomes, for Bateson, a mere disturbance that sullies an otherwise lovely experiment.
HUGO DE VR1ES: A MOST RELUCTANT NON-DARWINIAN
Dousing the great party of 1909
It must have been a grand show. Wallace and Hooker still lived, and happily attended to present their memories and current views. Darwin's son Francis helped with arrangements; while Sir George, his most academically accomplished [Page 416] offspring (and Plumian Professor of Astronomy at Cambridge), contributed an article on “The Genesis of Double Stars.” Charles Darwin (just plain Charles, for Victoria never d
id grant him a knighthood) had the good sense to publish his greatest work at age 50 — and the centenary of his birth therefore coincided with the 50th anniversary of the Origin. A grand occasion for a double celebration.
Cambridge University Press, at Darwin's alma mater, published the proceedings of his centennial party without delay in the right year of 1909, under the editorship of botanist A. C. Seward. The choice of participants had been ecumenical, ranging in profession from the great anthropologist J. G. Frazer (of The Golden Bough) to the equally celebrated historian J. B. Bury, and in attitude from such Darwinian stalwarts as Hooker and Weismann to such active opponents as William Bateson. All participants had their say and delivered both their praises and their criticisms. In this medley of maximal diversity, however, only one statement seemed so egregious to the editor that he felt compelled to make a public statement.
In his short preface, editor Seward acknowledged the pluralism of his volume in expressing “the divergence of views among biologists in regard to the origin of species” (1909, p. vii). Then, in a single sour note, he cried “foul” about one passage: “In regard to the interpretation of a passage in the Origin of Species quoted on page 71, it seemed advisable to add an editorial footnote; but, with this exception, I have not felt it necessary to record any opinion on views stated in these essays” (Seward, 1909, p. v).
Turning to page 71, we find ourselves in the midst of an article on “Variation” by the Dutch botanist Hugo de Vries (following Weismann and preceding Bateson in a fascinating bridge between opposites). De Vries had won widespread fame for his “Mutation Theory” on the origin of species (2-vol-ume German edition in 1901 and 1903; English translation in 1909). Most biologists viewed this saltational proposal (correctly so, I shall argue) as anti-Darwinian in mechanism. Yet de Vries persisted in trying to cover himself with the mantle of Darwin's presumed (though posthumous) approval. In the offending passage, de Vries twisted both logic and literary interpretation to argue that Darwin had really meant to identify saltational variation as the source of evolutionary change — whereas plain sense and everyone else's reading indicated that Darwin had favored insensible variation and rejected sports. De Vries wrote:
The Structure of Evolutionary Theory Page 66