ESSAY REVIEW Mr. Darwin's Critics, Old and New MICHAEL T. GHISELIN

Depart~rtent of Zoology and Bodega Marine Laboratory University of California, Berkeley

Peter J. Vorzimmer, Charles Darwin: the Years of Controversy, The Origin of Species and its Critics 1859-1882 (Philadelphia: T e m p l e University Press, 1970). History is a f o r m of strictly objective n a t u r a l science. J u s t as a paleontologist derives his history of life f r o m the rocks, not his fancy, a n historian of biology infers w h a t h a s h a p p e n e d f r o m the documents; he does not a p p r o a c h his subject as ff it were a b r a n c h of i m a g i n a t i v e literature. But a wealth of m a t e r i a l s m a y give rise to certain options, so t h a t by selecting alternative pieces of evidence, plausible a r g u m e n t s m a y be pieced together for contrary interpretations of the s a m e events. Especially with respect to Darwin, the opportunity for a scissors-and-paste a p p r o a c h to scholarship seems infinite. So m a n y opinions h a v e b e e n expressed in the secondary literature t h a t footnotes c a n m a k e any notion w h a t e v e r seem orthodox. The D a r w i n i a n corpus itself r u n s to something like 8,000 pages, not including the m a n y revisions, while the published correspondence fills several thick volumes. So prolific a n author c a n scarcely h a v e helped but fall into useful ambiguities. Add to this the wealth of m a t e r i a l s preserved in the C a m b r i d g e University archives, and a n y t h i n g goes. Peter J. V o r z i m m e r h a s based m u c h of his study of D a r w i n ' s relationships to his critics on a very limited sample of items f r o m D a r w i n ' s personal library and reprint collection. I h a v e m y own views on such m a t t e r s , ones w h i c h I have derived f r o m analyses of D a r w i n ' s published works. I n p r e p a r i n g this review, however, I have spent some weeks at Cambridge, and have gone over m u c h of the s a m e m a t e r i a l V o r z i m m e r did, as well as some which he m a y not have seen. 1 A look at such I. I a m m o s t grateful to the University, Saint Catharine's College, Dr. Sydney Smith, and Mr. Peter Gaut~ey for their h o s p i t a l i t y a n d a s s i s t a n c e .

Journal of the History of Biology, voL 6, no. 1 (Spring 1973), pp. 155-165.

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m a t e r i a l s will readily convince one of their utility-----especially, I think, in showing the f a c t u a l inadequacy and conceptual weakness of the older Darwin scholarship and its present-day following. I a m deliberately taking a strong position on these matters. They are too i m p o r t a n t to be passed over in silence, and should be debated openly. V o r z i m m e r h a s e m b r a c e d an orthodox anti-Darwinian position on the merits of Darwin's intellect and work, one t a k e n over f r o m the c o m m e n t a r i e s of authors with religious, m e t a physical, and political objections to the theory of n a t u r a l selection. By stressing the views of Darwin's critics, especially the Catholic apologist St.-George Mivart, and by failing to m e n t i o n evidence to the contrary, he comes u p with a superfieially plausible a r g u m e n t , but one which will not b e a r critical examination. By no m e a n s do I wish to imply that V o r z i m m e r h a s deliberately m i s r e p r e s e n t e d the facts. Rather, his text seems to indicate a great deal of wishful thinking and frequent lapses of the critical faculties. V o r z i m m e r errs on a n u m b e r of basic conceptual points, and these m i s t a k e s add to the confusion. One is t e m p t e d to wonder if the frequent allusions to Darwin's inconsistency don't simply m e a n t h a t Darwin's conclusions do not follow f r o m V o r z i m m e r ' s premises. 2 P e r h a p s the m o s t i m p o r t a n t misconception h a s to do with Darwin's m a n n e r of reasoning. V o r z i m m e r represents D a r w i n as a Baconian in the late nineteenth-century sense of t h a t term. 8 By implication D a r w i n would h a v e felt it necessary to support his theory with rigorously verified premises. M a n y of Darwin's critics felt that he should h a v e reasoned in this m a n ner, for they were themselves professed Baconians. But although some of Darwin's statements, especially if t a k e n out of context, m i g h t give the w r o n g impression, the correspondence leaves no r o o m for doubt. As h a s b e e n pointed out by Mayr, De Beer, and myself, D a r w i n used a "hypothetico-deductive" method, in the sense that his so-called "axioms" and " a s s u m p tions" were conjectures which he tested by reference to experim e n t s and controlled observations. Stripped to its bare essentials, the a r g u m e n t w e n t t h a t species do vary, t h a t artificial selection renders the m e c h a n i s m plausible, and t h a t a 'qaost of facts" are explicable if the theory is true, but not otherwise. Darwin, to be sure, treated the empirical side of r e s e a r c h w i t h the greatest respect, and opposed the speculative or "deductive" a p p r o a c h of Spencer and others. Also, the intellectual climate 2. Pp. 143, 2 7 0 and elsewhere. 3. P. 11.

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Mr. Darwin's Critics, Old and N e w of the times favored sticking to the facts, and he wrote in a style w h i c h appealed to c u r r e n t taste. Beginning f r o m his erroneous foundation, V o r z i m m e r finds a n excuse for stressing D a r w i n ' s not very successful efforts to fit the as yet u n k n o w n m e c h a n i s m s of heredity into his theoretical system, and an excuse for giving short shrift to D a r w i n ' s a c c o m p l i s h m e n t s in general. V o r z i m m e r h a s seriously m i s c o n s t r u e d a n u m b e r of Darwin's i m p o r t a n t theoretical concepts, and the analysis affects the whole book. Our suspicions are aroused w h e n V o r z i m m e r repeatedly uses the m o d e r n t e r m "speciation" in a m o s t heterodox fashion. 4 One needs to distinguish between two basic evolutionary processes: changes in gene frequencies on the one h a n d , and the f o r m a t i o n of reproductively isolated populations on the other. The two, of course, are closely interrelated, a n d we c a n easily u n d e r s t a n d w h y D a r w i n m i g h t h a v e h a d difficulty in accounting for both. V o r z i m m e r succeeds in explaining some of these issues, b u t on the whole he confuses r a t h e r t h a n clarifies. Isolation is one w a y to increase the rate of change in gene frequencies; it also is a necessary condition for speciation. D a r w i n probably would h a v e m o r e or less agreed with one or both of these propositions, except that he would h a v e argued t h a t although isolation favors both processes, it only helps, r a t h e r t h a n being absolutely necessary. The equivocal use of "speciation" seriously muddles the account in C h a p t e r Seven. The difficulty is c o m p o u n d e d w h e n V o r z i m m e r misinterprets w h a t D a r w i n m e a n t by "unconscious selection." D a r w i n argued t h a t isolation is not absolutely necessary for evolution to occur, on the grounds that a new breed of domesticated a n i m a l s m i g h t be f o r m e d deliberately (by picking out the desired v a r i a n t s and isolating t h e m ) , or else by effecting the c h a n g e unconsciously (by cherishing certain v a r i a n t individuals, but not keeping t h e m isolated). V o r z i m m e r treats this empirical a r g u m e n t against the necessity of isolation, and for the sufficiency of selection in spite of blending, as if it were a n ad hoc m e c h a n i s m by w h i c h the problems raised by blending inheritance could be explained away. This is, indeed, but one of several gratuitous allegations of ad hoc hypothesizing. A c o m p a r a b l e problem arises with respect to the issue of saltation: are the large or the small variations the m o r e imp o r t a n t in producing evolutionary c h a n g e ? V o r z i m m e r treats 4. E.g., pp. 21, 47, 135, and 284.

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the question as if it had to do mainly with the problems surr o u n d i n g inheritance. Vorzimmer muddles the issue by calling the mutations of twentieth-century genetics "saltations," and says that our m o d e r n views do not really m a t t e r in the context of nineteenth-century history. 5 He quite rightly points out that some of the more c o m m o n variations w h i c h we observe in both wild and domestic organisms are not i n h e r i t e d m t h e y are purely phenotypic rather than genotypic variations. Yet a m u t a t i o n would qualify as a "saltation" only in the sense that it forms a discontinuous step: it is not inevitably a saltation in the sense of a big change. We now know that the small-scale variability is indeed the basis of change. Mutation is its ultimate source, but most of it in any given individual has been produced by genetic recombination. Yet the phenotype-genotype distinction was a later innovation, irrelevant in the context of Darwin's research. He saw no qualitative difference between the two kinds of variation large or small, they could all be interpreted as modifications of developmental mechanisms. He had w h a t seemed to h i m good evidence, namely, a continuous series, that the differences are a m a t t e r of degree. Insofar as Darwin inferred that the more c o m m o n forms of variability are the ones more likely to produce evolutionary change, we need see no more than a shift in emphasis here. How m u c h significance we should attach to efforts at explaining away difficulties in the theory, and how m u c h to attempts at working out its detailed implications, deserve the serious attention of historians. Vorzimmer never gives Darwin the benefit of a doubt. Nowhere do we find Vorzimmer's repeated charges of ad hoc hypothesizing rigorously substantiated. These allegations have to do, for the most part, with Darwin's c o m i n g to accept alternative m e c h a n i s m s of evolutionary change in the face of criticism. Vorzimmer minimizes the importance of such alternatives in Darwin's earlier publications. The whole argum e n t is very difficult to rebut, because it largely rests on opinions as to the "impression one generally gets" f r o m reading Darwin's works. I dare say that at least one reader gets a different impression. Admitting that Darwin h a d accepted the existence of other causes, Vorzimmer nonetheless m a i n t a i n s that "since the hypothesis of n a t u r a l selection was based on the selective accumulation of variations on the basis of utility, and since Darwin himself put it so firmly 'every detail of 5. P. 276.

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Mr. Darwin's Critics, Old and N e w structure in every living creature' either was or is 'of special use,' it hardly seems as if he w a s e n t e r t a i n i n g any other possibility at the time." e The original p a s s a g e f r o m the first edition of the Origin of Species ( w h i c h V o r z i m m e r quotes earlier with a m i n o r error) reads "Hence every detail of structure in every living creature ( m a k i n g some little allowance for the direct action of physical conditions) m a y be viewed, either as h a v i n g been of special use to some ancestral f o r m , or as being n o w of special use to the descendants of this f o r m - - - e i t h e r directly, or indirectly t h r o u g h the complex laws of growth." 7 Elsewhere in the s a m e work D a r w i n writes Yet I fully a d m i t that m a n y structures are of no direct use to their possessors. Physical conditions probably h a v e h a d some little effect on structure, quite independently of any good thus gained. Correlation of growth h a s no doubt played a m o s t i m p o r t a n t part, and a useful modification of one p a r t will often h a v e entailed on other p a r t s diversified changes of no direct use. So again c h a r a c t e r s which formerly were useful, or which f o r m e r l y h a d arisen f r o m correlation of growth, or f r o m other u n k n o w n cause, m a y r e a p p e a r f r o m the law of reversion, though n o w of no direct use. The effects of sexual selection, w h e n displayed in beauty to c h a r m the females, c a n be called useful only in r a t h e r a forced sense, s And w h e n we realize t h a t D a r w i n ' s references to correlated growth go b a c k to his notebooks on t r a n s m u t a t i o n of species, we obtain a s o m e w h a t different view of the documents. The foregoing quotation bears u p o n another i m p o r t a n t issue, sexual selection, w h i c h V o r z i m m e r , true to form, a t t e m p t s to convince us w a s an ad hoc hypothesis. He admits t h a t D a r w i n h a d invented the idea long before he wrote the Origin of Species, but insists u p o n treating it as if it h a d been pressed into service later on to explain away the origin of useless characters. T h u s he misses the whole point. As sexual selection is a f o r m of pure reproductive competition, it provides a good a r g u m e n t for selection theory in general. Features h a v e evolved w h i c h are n o n a d a p t i v e or even m a l a d a p t i v e f r o m the point of view of the species. The "rather a forced sense" of their utility, to which D a r w i n referred, h a s to do with the adaptations w h i c h some o r g a n i s m s m i g h t possess if, and only if, Darwin's 6. Pp. 2 2 0 - 2 2 1 . 7. P. 200. 8. P. 199.

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theory were true. Vorzimmer m a n a g e s to see that the differences separating Darwin and Wallace had something to do with individual and group advantages. And he rightly points out that Wallace came to occupy the same position as did Mivart. But it is not m a d e sufficiently clear that the issue here was partly metaphysical and religious. Wallace never really came to grips with the maladaptive side of natural selection; he rejected selection as the m e c h a n i s m which produces m a n ' s distinctive psychological properties; and he became a spiritualist in his old age. While n a t u r a l selection permits one to believe in an order instituted by God, sexual selection makes a travesty out of the whole Christian cosmology. The literature, historical and otherwise, suffers greatly f r o m efforts to rescue God f r o m the predicament in which Darwin put him. Might we not likewise question Vorzimmer's allegations of ad hoc hypothesizing with respect to "Lamarckian" ideas and pangenesis? 9 We search in vain for any fact that is explicable only on the basis of their h a v i n g been invoked for this reason. With respect to inherited habit at least, the alleged shift to L a m a r c k i a n i s m c a n n o w be refuted, for Darwin presupposed it---even before he read M a l t h u s - - i n his unpublished notebooks "M" and "N." Along similar lines, we ought to suspend judgm e n t until we receive a more definite statement than a mere assertion that Darwin "was unable to demonstrate the necessity or sufficiency of n a t u r a l selection as the causal agent of evolution." lo We are not told in relation to what, or in w h a t sense, the theory ought to be necessary and sufficient. The statement "Cyanide is poisonous" is neither necessary nor sufficient to explain why people die. Persons whose stomachs do not secrete acid m a y live, in spite of taking it, and there are other causes of death. But the toxic properties of cyanide can still be invoked as a reason for certain people being killed. Shifting to a less theoretical plane, we find that Vorzimmer gives a most one-sided chronicle of Darwin's relationships to his critics. We are not told that m u c h of the criticism was cast in the f o r m "I c a n n o t imagine x, therefore y." On the whole, Darwin and his supporters answered these very well, putting Mivart and Jenkin in a rather embarrassing position. If ignorance and lack of imagination had been the real reason for some of the criticisms, w h y not the rest as well? Vorzimmer's account of the exchanges with Mivart m i g h t just as 9. Pp. 234, 256 a n d 271. 10. P. 270; see also p. 249.

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Mr. Darwin's Critics, Old and New well have been written by Mivart himself. 11 We are told virtually nothing about the alternative hypothesis which Mivart supported, one which is basically the same as that advocated by Richard Owen. The idea was a version of orthogenesis, in which species develop in a m a n n e r analogous to the embryological development of individuals, coupled with a notion that ontogeny m a y be compared to crystallization. This traditional point of view implied a divine order, including such virtually miraculous happenings as horses evolving to provide h u m a n i t y with transportation. TM The polemic involved this basic difference in the hypothesized mechanisms, and he who overlooks this point ignores the context. By stressing the problems of inheritance, Vorzimmer makes Mivart's attacks seem effectual. Yet w h e n we read Mivart's brief, anonymous review of 1869, and his Genesis of Species, which is really only an expanded version, we get another impression. Darwin's annotations in his own copies are most instructive, particularly w h e n we see how well his vastly superior learning and imagination provided immediate and effectual answers. To the lack of fossil intermediate forms, Darwin responds "Amchaeopteryxl" 13 W h e n Mivart asks why there are not more species of giraffe, Darwin notes '~Did not v a r y - - a l r e a d y a leaf eater &c. &c." 14 Mivart asks how the early stages of new structures could originate, giving the example of climbing plants. Darwin replies "See m y paper." 15 Those who have read Darwin's book on climbing plants will know that the answer in this case has to do with pre-adaptations and function shifts. It is just such effective rebuttal that Vorzimmer leaves out. Mivart's efforts to refute natural selection and to substantiate his orthogenetic notions were largely based upon instances of convergent evolution. He found, he said, the similarities that have evolved between quite unrelated organisms beyond the power of his imagination to explain without some principle additional to natural selection. A good comparative anatomist, such as Darwin, can see through Mivart's superficial examples at once, and has no trouble refuting orthogenesis. Mivart gives 11. For a m u c h m o r e balanced account see Jacob W. Gruber, A Conscience in Conflict: the Life of St. George Jackson Mivart (New York: C o l u m b i a University Press, 1960). 12. St. George Mivaxt, On the Genesis of Species (London: Macmillan, 1871), pp. 133-134. 13. Anonymous (St. George Mivaxt), "Difficulties of the theory of natural selection," The Month (1869), pp. 26-28 of Darwin's copy. 14. Ibid., p. 9. 15. Mivaxt, Genesis of Species, p. 107.

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as an e x a m p l e the dental r e s e m b l a n c e s between the true wolf and the m a r s u p i a l "wolf." D a r w i n c o m m e n t e d "If it is so tooth for t o o t h ? ? ? " L a t e r he added the different dental formulae. 16 I n the n i n t h c h a p t e r of The Genesis of Species Mivart raises n u m e r o u s objections to the efforts of D a r w i n and others to account for the origin of morality. Darwin's m a i n work on this subject h a d yet to be published, but the attack w a s soon renewed in a review of The Descent of Man. The f u n d a m e n t a l reason for their d i s a g r e e m e n t is obvious: the very idea t h a t brutes h a v e morals, or t h a t morality c a n be treated as a f o r m of ultimate self-interest was an issue of such i m p o r t a n c e that it could scarcely be i g n o r e d - - b u t V o r z i m m e r does not m e n tion it. 17 He asserts instead that Mivart gives quotations f r o m Darwin's writings that show that the theory of n a t u r a l selection h a d broken down. D a r w i n had, to be sure, stated possible discoveries that could refute his theory. These were ( 1 ) a c h a n g e which could not possibly h a v e been produced by small, gradual steps, ( 2 ) an adaptation in one species solely for the good of another species. Mivart m a k e s a very m u d d l e d c o m m e n t on these criteria of refutation, m i s r e p r e s e n t i n g Darwin's position, and V o r z i m m e r fails to tell us w h a t either really said. The notion that Mivart was able "to topple over the entire theory" will astound anyone who has r e a d the documents. 18 It seems r e m a r k a b l e that V o r z i m m e r would conclude that Mivart and the other critics h a d succeeded in 'qgadgering the elderly D a r w i n into the state of f r u s t r a t i n g confusion which m a r k e d h i m on the eve of his retirement." 19 This so-called "retirement f r o m public participation in m a t t e r s strictly concerned with the principle of evolution b e g a n shortly after he dispatched his revised m a n u s c r i p t of the sixth Origin in J a n u ary 1872." 5o ("Strictly" is not defined; n o r is "shortly after" - - s o we do not know to w h a t extent this applies to The Expression of the Emotions.) Afterwards, we are told, his publications were no longer on evolution: '%lot one of these works m a d e any direct contribution to his theory. Even indirectly, as supporting evidence for the action of n a t u r a l selection, D a r w i n omitted all but the rarest allusions to aspects of his theory." el Again, "Darwin's botanical works were intended 16. 17. 18. 19. 20. 21.

Mivart, "Difficulties of the t h e o r y of n a t u r a l Pp. 243-244. P. 243. P. 251. P. 250. P. 254.

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p. 14.

Mr. Darwin's Critics, Old and N e w to be strictly separate, non-evolutionary works." 22 These fantastic notions, albeit in line with V o r z i m m e r ' s thesis, c a n only m e a n that ff V o r z i m m e r h a s actually r e a d the books in question, he h a s either failed to u n d e r s t a n d t h e m or to a d m i t the obvious. Darwin's later publications were all intended to w o r k out i m p o r t a n t implications of his theory. The oversight is all the m o r e r e m a r k a b l e w h e n we realize that the botanical researches, as V o r z i m m e r himself admits, b e g a n long before the so-called retirement. Some of D a r w i n ' s e x p e r i m e n t s on peloric flowers, for e x a m p l e , were discussed in The Variation of Animals and Plants under Domestication. V o r z i m m e r m e n t i o n s the early botanical work on orchids, b u t misses the point. The book is on m a l a d a p t a t i o n and w h a t h a s been called "opp o r t u n i s m " - - n o t a n effort to show t h a t the p a r t s of flowers are useful after all. Insectivorous Plants, and, as I m e n t i o n e d above, Climbing Plants, a t t e m p t to d o c u m e n t the acquisition of n e w features by g r a d u a l modification of old ones. The s a m e t h e m e is continued in The Power of Movement in Plants. Cross- and Self-Fertilisation deals with such topics as the effects of inbreeding, the origins of sterility, and the adaptive significance of sex: these were as i m p o r t a n t to D a r w i n as they are to the evolutionary biology of our o w n day. The Different Forms of Flowers on ( n o t of) Plants of the Same Species is concerned with inbreeding and outbreeding. Surely, this is no "non-evolutionary" work. Finally, a n u m b e r of Darwin's later works, including not only his book on w o r m s and emotional expression, but some of the botanical ones as well, fulfilled a prediction e n u n c i a t e d in the first edition of The Origin of Species: ' T s y c h o l o g y will be b a s e d on a new foundation, that of the n e c e s s a r y a c q u i r e m e n t of e a c h m e n t a l power and capacity by gradation." 28 I should add in passing t h a t Darwin's psychological r e s e a r c h w a s b e g u n very early. Although it always w a s strongly evolutionary in outlook, it m a y be traced b a c k to the period before he h a d invented the hypothesis of n a t u r a l selection. As m a y be seen f r o m notebooks "M" and "N," D a r w i n w a s profoundly interested in epistemology and the evolution of morals; and here we c a n also find the beginnings of his work on emotional expression and sexual selection. It was not "for a m u s e m e n t " that D a r w i n r e a d Malthus, but r a t h e r because of a profound interest in m o r a l philosophy and social behavior. D a r w i n n e v e r retired. Before the age of thirty he h a d seen how the theory of evolution 22. P. 254. 23. P. 488.

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could t r a n s f o r m our entire world-view. He spent the rest of his days elaborating upon this single theme; but nobody understood. By going through the m a n y works in w h i c h Darwin presented versions of his theory, Vorzimmer has m a n a g e d to enumerate the more obvious changes in emphasis. One m i g h t debate whether this positive contribution outweighs the a m o u n t subtracted. The book contains factual material that is h a r d to come by otherwise, but this comes so mixed up with distortions and outright errors that only an expert c a n use it. We are told that Darwin had an idea of selection as an evolutionary m e c h a n i s m while still on the Beagle. z4 This view, if true, should have been documented, for the weight of evidence now available shows that the idea of n a t u r a l selection was a fairly late development. Isidore Geoffroy Saint-Hflaire is confused with his father, and the latter's notion of "connections" should have been kept terminologically distinct f r o m Cuvier's principle of the correlation of parts. 25 S u m m i n g up, Vorzimmer has missed an opportunity to say something really new, and has merely repeated and illustrated the traditional mythology. The rest of us can derive a valuable lesson f r o m his example. Avoid overconfidence: one can easily underestimate the difficulties of the theory and the brilliance of its founder. We m u s t also take note that Darwin wrote at a time w h e n the new science of evolutionary biology was only beginning to develop a precise and unambigious vocabulary. Hence he h a d every reason to express himself in analogical and metaphorical language. His critics have not, in the long run, escaped censure for interpreting his words in a sense that was not intended by the author. Darwin was also given to understatement, and to only suggesting, or at least not stating explicitly, the implications of his work. The need to read between the lines becomes all the more imperative because he addressed a learned nineteenth-century audience, and m u c h that he says is clear only to someone who knows the literature. Since Darwin worked on a broad range of difficult problems, the task of interpreting his works d e m a n d s a great deal of preparation. And this preparation m u s t include a knowledge of biology sufficient for w h a t one sets out to do. As a professional evolutionary biologist, I never cease to be dismayed by the cavalier u n c o n c e r n for profundities with w h i c h outsiders treat the subject. Somehow our educational 24. P. 3. 25. Pp. 25, 40 a n d 85.

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Mr. D a r w i n ' s Critics, Old and N e w institutions h a v e failed to get the m e s s a g e across: the study of evolution isn't easy. On the other h a n d , since so little good work on D a r w i n h a s yet been done, there are a b u n d a n t opportunities for those who c a n m e a s u r e u p to the task. To the aspiring D a r w i n scholar I c a n r e c o m m e n d nothing m o r e strongly t h a n a close, analytical reading of everything t h a t D a r w i n ever published. With practice one soon develops a feeling for Darwin's style, for his m a n n e r of reasoning, and for the larger syntheses toward which the separate works all lead. His published letters, easily obtained, should also be read, for the dialogue tends to be m o r e explicit and to the point. Finally, one c a n learn a great deal by r e a d i n g a selection of the works which D a r w i n used, giving particular attention to theoretical issues. Only at this stage do the u n p u b l i s h e d m a t e r i a l s begin to add m u c h of value, and even then one c a n do good, original work without them. The annotations in Darwin's library show w h a t attracted his attention, w h a t seemed i m p o r t a n t , and w h a t he thought should be r e m e m b e r e d . T h e y also contain speculations a n d once in a while the sort of d e v a s t a t i n g criticism that an author deserved, b u t which n e v e r m a d e its w a y into print. Unlike the published works, addressed to everybody who h a p p e n e d to be interested, or the autobiogr a p h y and letters intended for his children or correspondents, the notes were for D a r w i n himself. Hence, albeit m o r e difficult to interpret, they provide a kind of insight that is h a r d to obtain f r o m any other source. But w h a t e v e r one's materials, it always helps to keep the p a s t failures in D a r w i n studies in mind. Darwin's a c c o m p l i s h m e n t s c a n never be argued away, especially by historians who do not u n d e r s t a n d them.

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