If Marx and Engels did not laud Darwin in any of their formal publications might they have privately acknowledged Darwin's scientific findings as providing the basis for his political ideology? No, as we shall see, this avenue too is a historical cul-de-sac. Nevertheless, according to Bergman (2001):

"Marx and Engels ‘enthusiastically embraced’ Darwinism, kept up with Darwin’s writings, and often corresponded with each other (and others) about their reactions to Darwin’s conclusions."

This claim deserves to be examined in some detail because it is so far removed from the truth. First, as we have already seen from their publications it is simply not the case that either Marx or Engels "enthusiastically embraced" Darwinism and this lack of enthusiasm spills over into their correspondence. Bergman has worded himself cautiously here with the phrase "often corresponded". He has not quantified their degree of correspondence because he cannot do so without disclosing to the reader that these communications were exceedingly rare. Furthermore, "their reactions to Darwin’s conclusions" were rarely positive in tone, being, in the main, innocuous and more often negative.

The facts are these: The first mention of Darwin in their personal correspondences occurs in 11/12th December 1859 in a letter from Engels to Marx. Following the day of that letter to the day Engels died in 1895, there are 3,104 letters written by either Marx or Engels now archived (Marx & Engels Collected Works, 1931). A search through the archive for the term ‘Darwin’ or any variants using that term as a prefix (e.g., ‘Darwinism’, ‘Darwinian’ or ‘Darwinist’) reveals only 38 letters containing at least one instance of any of these words; 20 written by Marx and 18 by Engels. This represents 1.22% of all of their personal correspondence for that period. Furthermore, in the period 1860-1864, i.e., the first five full years following publication of ‘On the Origin of Species’ (1859) which Marx supposedly "enthusiastically embraced", he wrote 265 letters, yet only four contain the search terms (1.51%). In that same period, Engels wrote 98 letters and none include the search terms. Neither did their enthusiasm increase over time. An analysis of each man’s last decade of life reveals no increased prevalence for the search terms. Marx wrote 276 letters from the beginning of 1874 to his death in 1883 and the search terms occur on only three occasions (1.09%). Engels wrote 961 letters from the beginning of 1886 to his death in 1895, the search terms are found on only two occasions (0.21%). This rate of correspondence would surely not meet any reasonable criterion for "often corresponded." (Bergman, 2001); it would surely be more accurate to state that they very rarely corresponded about Darwin or evolutionary theory.

What follows is a discussion of each mention of the word Darwin or variants in these private letters, presented chronologically, when necessary with some discussion of context. The majority of the letters contain entirely mundane and innocuous comments pertaining to the search terms but they are included here because they patently demonstrate the relative lack of attention and respect Marx and Engels gave to Darwin and his scientific findings. There are very few with words of praise and some convey a distinct tone of negativity. Except where noted, all translations are from the Lawrence and Wishart version of Marx-Engels Collected Works (2010; Volumes 40-50). Quotes from Darwin’s personal correspondence are from the Darwin Correspondence Project (ongoing).

Letter 1: Engels to Marx. 11th/12th December 1859. Although always considered as the junior partner to Marx, Engels was nevertheless far more interested in the explosion in growth of the biological and physical sciences in the mid-19th century. He seems generally more knowledgeable on scientific matters than Marx. For example, in a letter to Marx the previous year (14th July 1858) Engels notes a number of recent discoveries in such diverse fields as chemistry, physiology, botany and physics and this discussion makes up the bulk of his letter. However, replying to Engels the next day, Marx completely ignores the discussion of science and concentrates on his current financial circumstances.

Engels was fortunate to have purchased one of the first 1,250 copy print run of ‘On the Origin of Species’ (which had sold out within 24 hours) on 24th November 1859, and almost three weeks later he wrote to Marx. There are two separate references to Darwin in this letter. In the first, the German poet Gottfried Kinkel incurs Engels’ wrath following his role in causing a split in the Communist League in 1850. Engels was incensed by this because he and Marx had written ‘Manifesto of the Communist Party’ (1848a) at the request of the League. Here, Engels employs a veiled criticism of natural selection in order to insult Kinkel and his followers:

"Whole generations of crippled moles having, by the Darwinian process of NATURAL SELECTION, evolved to the highest degree the faculty to live on dung, with shit for their chosen element."

After releasing his venom on Kinkel he then shifts to the more amenable topic of Darwin’s attitude to teleology:

"Darwin, by the way, whom I’m reading just now, is absolutely splendid. There was one aspect of teleology that had yet to be demolished, and that has now been done. Never before has so grandiose an attempt been made to demonstrate historical evolution in Nature, and certainly never to such good effect. One does, of course, have to put up with the crude English method."

This is the first inkling we have as to what initially attracted Engels to Darwin. He commends Darwin to Marx, not for introducing the concept of natural selection to biology, but solely for discussion of a lack of teleology in nature, i.e., nature devoid of any supernatural or otherwise purposeful input. Nevertheless, it is important to note that Engels’ view of teleology was decidedly idiosyncratic and differed in an important way from Darwin. While Darwin (1859) described a non-teleological evolutionary process without apparent design, purpose or predetermined goals, Engels (1883a) considered that:

"The old teleology has gone to the devil, but the fact firmly stands that matter in its eternal cycle moves according to laws, which, at a certain stage – sometimes here and sometimes there – necessarily produces the thinking mind in organic beings.......we have the certainty that matter remains eternally the same in all its transformations, that none of its attributes can ever be lost, and therefore, also, that with the same iron necessity that it will exterminate on the earth its highest creation, the thinking mind, it must somewhere else and at another time again produce it."

Thus, Engels did appear to harbour at least some notion of teleology. He simply attempted to replace supernatural teleology with a natural teleological mechanism that somehow had the pre-determined “internal necessity” of creating life and proceeding toward evolving complex, intelligent minds (Engels, 1883a; Paul, 1979). He certainly did not imply any conscious purpose; rather he considered that it was a natural tendency within nature that inevitably unfolded given fortuitous environmental conditions. One could conjecture this was a vestige of his upbringing in a strongly Calvinist family; Calvinism arguably being the Christian sect that most emphasises the notion of a divine teleology or strong determinism. That said, ‘On the Origin of Species’ did not seem to have appealed to Engels that greatly for he made no further mention of Darwin in his personal correspondence for another five years.

Letter 2: Marx to Engels. 19th December 1860. The first occasion in which Marx mentions Darwin occurs a full year after Engels had recommended ‘On the Origin of Species’ to him. He writes:

"In my times of trial [referring to an illness] during the last four weeks - I have read all sorts of things. Among others, Darwin's book on Natural Selection. Although it is developed in a crude English way, this is the book that contains the natural-history foundation of our view point."

Letter 3: Marx to the Prussian-German philosopher Ferdinand Lassalle. 16th January 1861. Although he never actually mentions the title, Marx makes an obvious reference to ‘On the Origin of Species’:

"One does, of course, have to put up with the clumsy English style of argument. Despite all shortcomings, it is here that, for the first time, ‘teleology’ in natural science is not only dealt a mortal blow but its rational meaning is empirically explained."

Notice how, in all letters so far, they both disparage Darwin’s theory by referring to the building of his case as "crude" and "clumsy". Like Engels, although Marx briefly mentions natural selection, in neither letter does he elaborate. It is the “mortal blow” to teleology that interests him. It was Darwin’s impact on the notion of teleology in the biological sciences that interested Aveling (1897) too:

"Is there one special doctrine that Darwin has taught by which he will be especially remembered in the after ages? I think there is.......Probably most of my readers will at first sight think that this is the theory of Natural Selection or the survival of the fittest.......But I do not select this as the most important of Darwin’s theories.......until the time of Charles Darwin the popular, and in truth the scientific, conception of Nature was that all things were ordered and designed by some great power or powers from without; that there was a beginning of things in which matter and motion were created ; that the various forms of matter and various forms of motion were superintended and interfered with from without, and that the final destructibility of matter and motion was conceivable. It was reserved for Darwin to tell us that these conceptions were inaccurate."

But there is a far more important comment in both Marx’s letter to Engels (Letter 2: 19th December 1860) and here to Lassalle that exercises certain anti-Darwinian authors so much. It the final sentence in Marx’s letter to Engels quoted above and it immediately precedes the quote given from the letter to Lassalle. The two sentences are similar but the Lassalle version is the smoking gun, being far more commonly cited and so is discussed here. In the original German the manuscript reads verbatim:

"Sehr bedeutend ist Darwin's Schrift u. paßt mir als naturwissenschaftliche Unterlage des geschichtlichen Klassenkampfes."

This is not a particularly difficult sentence to translate and it translates most simply as:

"Very significant is Darwin’s writing [which] suits me as a scientific document of the historical class struggle."

There are differences, however, in the various translations and some more than subtly alter its meaning. The following version seems to be the most commonly found in the American literature (e.g., Marx-Engels Collected Works, 1924):

".......this is the book that contains the natural historical foundation of our outlook."

The 1924 American version appears truncated compared to the 1931 translation from Progress Publishers, the official Soviet government publishers of Marx's writings. Their version reads:

".......suits my purpose in that it provides a basis in natural science for the historical class struggle."

It seems obvious that the 1924 American version is a relatively poor translation compared to the 1931 Soviet version. It is closer to the version in Marx’s letter to Engels (Letter 2: 19th December 1860) than the one addressed to Lassalle. Most notable is the American substitution of the plural "our" for the first person "my", resulting in the vague (and incorrect) phrase "our outlook", echoing somewhat the version in the letter to Engels, "our viewpoint." Yet, in the original German, the sentence in the Lassalle letter clearly ends with the words "geschichtlichen Klassenkampfes" which has only one meaning: "historical class struggle." When Marx is writing to Engels, it appears likely that this is what he intended to convey but felt he didn’t need to expand as Engels would be aware that is what he meant. After all, the class struggle was and is at the very heart of Marxist political philosophy. The original Lassalle version also contains the word "naturwissenschaftliche" which is also missing from the 1924 American translation.

Nonetheless, these discrepancies pale in significance when compared with the version Morris (1963) and Bergman (2001) offer. This is surprising because when Bergman makes the claim that Marx and Engels’ personal correspondence is full of discussions about Darwin he quite reasonably references the respected 1934 translations of their correspondence performed by the British socialist historian, Dona Torr. She was fluent in German and had performed the translations, many from the original documents, at the Russian State Archive in Moscow and her final work was simultaneously published in the US and UK. However, when it comes to the only occasion in his article in which Bergman (purportedly) employs a quote from Marx he chooses and cites a translation from Zirkle (1959). It reads:

"Darwin’s book is very important and serves me as a basis in natural selection for the class struggle in history."

Quite obviously, this quote has been doctored. It is one thing to translate the words "naturwissenschaftliche unterlage" (‘scientific document’) as "natural historical" (1924) and "natural science" (1931). It may be, strictly speaking inaccurate, but neither greatly alters Marx’s original sense and both were legitimate synonyms within the context, at the time Marx was writing. However, it is quite another to smuggle in a phrase that does not exist in the original at all. It is reprehensible for Morris and Bergman to use the quote to bolster their arguments while surely aware that it is bogus. The original German text does not contain the words 'natürliche selektion' and no widely accepted edition of translations (e.g., Marx-Engels Collected Works: International Publishers, 1924; Progress Publishers, 1931; Torre, 1934; International Publishers 1942; Progress Publishers 1975; Lawrence & Wishart, 2010) includes ‘natural selection’ in that sentence. Bergman is happy to cite Torr when he thinks it suits him, yet eschews Torr’s (and others’) translations when they don’t convey what he wants; only via Zirkle’s doctored version can he marry Darwinian natural selection to Marx.

However, there is more to this story and it backfires on Bergman in the same way as referencing Pannekoek (1912) does. Zirkle famously had no time for Marxist thought of any kind. He was a professional biologist, fully in accord with the neo-Darwinian science of the time and a vehement critic of the official Soviet anti-Darwinist attitude toward biology during the Stalin era, evidenced in his 1949 book, ‘The Death of Science in Russia’. The later 1959 book of Zirkle’s, the one Bergman cites, is a history of evolutionary theory that robustly criticises the infiltration of Marxist ideology within biology generally. As Zirkle straightforwardly wrote:

"Quackery has penetrated into our scholarly world.......the coexistence of our rapidly expanding sciences with stupid quack substitutes for science should surprise no one.......the biology embedded in the social sciences approaches closest to the biology of Marx and Engels.......sociologists postulate biological principles which have long been disproven and which are so far removed from the ignored recent discoveries that at present sociological biology has almost nothing in common with the biology of the biologists."

Zirkle’s analysis is not what Bergman wishes to convey to his readers. That evolutionary biology and Marxist political philosophy are wholly incompatible and amount to "the biology of the biologists" vs. "stupid quack substitutes for science" is certainly not Bergman’s view. After all, he has a lifetime’s publications in creationist magazines arguing that both evolutionary biology and Marxism have inextricable philosophical connections and are empirically and morally wrong. They are both "stupid" and "quack" in his view. Yet Zirkle clearly views Marx and 20th century Marxists generally as less than sincere than biologists and contends that Marx was simply fishing for some scientific street cred, hence "serves me as a basis."

Despite being lukewarm at best toward Darwin’s works in his own writings, Engels nevertheless saw fit to mention Darwin at Marx’s funeral on 17th March 1883 at Highgate Cemetery in London:

"Just as Darwin discovered the law of evolution in organic nature, so Marx discovered the law of evolution in human history.......[He] discovered the special law of motion governing the present-day capitalist mode of production, and the bourgeois society that this mode of production has created. Such was the man of science."

Engels’ published the eulogy a week later in the journal of the Socialist Workers Party of Germany ‘Der Sozialdemokrat’ (1883b) and this is also commonly touted as evidence that Darwin had influenced Marx and Engels. It is no such thing. There were only nine people at the funeral, including Engels. Two others, Aveling and Liebknecht, gave brief speeches and a single telegram was read out. None except Engels mentioned Darwin. Only two scientists attended and neither gave a eulogy or wrote of the funeral afterward. One was Carl Schorlemmer, the Professor of Chemistry who had given Marx Darwin’s address. The other, Ray Lankester, was a zoologist who fully accepted Darwinian biological evolution (though some consider that in later life he became semi-Darwinian) but who had no truck with Marx’s politics. He had befriended Marx a few years earlier after Marx had approached him to recommend someone for medical treatment for his wife’s cancer. Lankester appears to have later regretted his brief friendship with Marx. On the 50th anniversary of Marx’s death, he found himself the sole living person to have attended his funeral but despite many requests, refused to provide any reminiscences or allow any interviews.

Engels’ words at Marx’s graveside (and Liebknecht’s memoir) seem a somewhat sad attempt to hang Marx on the coat tails of the scientific and social success that Darwin had so obviously achieved and Marx so obviously not (Ali, 1944). Liebknecht’s memoir, Engels’ eulogy (along with a reiteration in Engels’ preface to the 1988 English reprint of the Communist Manifesto) are clearly attempts to equate the two men in intellectual stature. However, neither count as anywhere near sufficient evidence that Darwin had influenced Marx. More to the point, in neither case do either of these men actually state this. Engels may have had philosophical problems with Darwin’s theory but he was happy to use Darwin’s fame for propaganda purposes (Megill, 2002; Stack, 2003). As Stack (2003) puts it, Engels was simply:

".......keen for Marxism to bask in the reflected glory of Darwinism [with his] attempt to steal the Darwinian mantle."

Letter 4: Marx to Engels. 18th June 1862. We must wait almost a year and a half to pass for the next mention of Darwin in correspondence. Now, it becomes obvious that Marx did not follow Darwin’s work particularly closely as he writes:

"I am amused at Darwin, at whom I have been taking another look."

This short passage being the sole flimsy evidence that leads Bergman (2001) to claim that Marx:

".......was so enthusiastic that he re-read it [‘On the Origin of Species’] two years later."

Marx continues, gently chiding Darwin:

"[I] should say that he also applies the ‘Malthusian’ theory to plants and animals, as though in Mr Malthus’s case the whole thing didn’t lie in it’s not being applied to plants and animals, but only – with its geometric progression – to humans as against plants and animals. It is remarkable how Darwin rediscovers, among the beasts and plants, the society of England with its division of labour, competition, opening up of new markets, ‘inventions’ and Malthusian ‘struggle for existence’. It is Hobbes’ bellum omnium contra omnes [war of all against all] and is reminiscent of Hegel’s Phenomenology, in which civil society figures as an ‘intellectual animal kingdom’, whereas, in Darwin, the animal kingdom figures as civil society."

Once again, Marx shows that he reads Darwin only through a Malthusian veil.

Letter 5. Marx to Dutch tobacco merchant, Lion Philips. 25th June 1864. We have to jump a full two years before either Marx or Engels again mention Darwin. Lion Philips was the husband of Marx’s maternal grandmother’s sister (he addresses him as ‘Uncle’), and one of Marx’s most generous financial benefactors. Here Marx is alluding to a controversial book by the Dutch orientalist Reinhart Dozy (1864) who argued that the Jewish religion and all of its patriarchs as described in the Pentateuch was all a deliberate fabrication to pave the way for strict monotheism, which has since led to Islam. Marx came from Jewish families on both sides. His father was originally named Hirschel Ha Levi and had Germanised his name to Heinrich Marx in order to practice law. His paternal grandfather was Rabbi Marx Ha Levi Mordechai. Marx's mother's family had included rabbis in each generation for at least the previous century before his birth. Marx, however, was atheist. This brief comment seems intended to portray his lack of kinship with Judaism:

"However, since Darwin demonstrated that we are all descended from the apes, there is scarcely ANY SHOCK WHATEVER that could shake 'our ancestral pride'."

Letter 6. Engels to Marx. 11th March 1865. This bland passage occurs nine months later. It concerns a short book written by the German philosopher and sociologist Friedrich Albert Lange, ‘Die Arbeiterfrage in ihrer Bedeutung für Gegenwart und Zukunft.’  (1965; ‘The Labour Question in its Present and Future Significance’):

"Siebel has sent me Lange's pamphlet. Confused, Malthusian with some Darwinian ingredients, flirting with all and sundry, but several good passages against Lassalle and the bourgeois consumers' co-op fellows. I'll send it to you in the next few days."

Letter 7. Engels to Friedrich Albert Lange. 29th March 1865. Later the same month Engels writes to Lange informing him that he has read his work and he makes a brief reference to Darwin, demonstrating that he too appears to lack an appreciation of the differences between Malthus and Darwin:

"I read it with great interest. I, too, was immediately struck on first reading Darwin by the remarkable similarity between his description of the vegetable and animal life and the Malthusian theory."

Engels then proceeds to accuse Malthus of plagiarism (a charge repeated by Marx in the first volume of ‘Das Kapital’):

"The parson Malthus filched this theory, like all his other ideas, directly from his predecessors."

Letter 8. Marx to Engels; 7th August 1866. Nearly a year and a half has passed and Marx recommends a recently published book by the French architect and photographer Pierre Trémaux (1865) outlining an alternative mechanism for speciation. It is obvious that Marx prefers Trémaux’s ideas to Darwin’s and he even makes several digs at Darwin’s expense:

"A very important work which I shall send on to you (but on condition that you send it back, as it is not my property) as soon as I have made the necessary notes, is: P. Trémaux, Origine et Transformations de l’Homme et des autres Êtres, Paris 1865. In spite of all the shortcomings that I have noted, it represents a very significant advance over Darwin."

This trend continues through the letter:

"The physical features of the earth, on the other hand, differentiate (they are the chief, though not the only basis). Progress, which Darwin regards as purely accidental, is essential here on the basis of the stages of the earth’s development, degeneration, which Darwin cannot explain, is straightforward here; ditto the rapid extinction of merely transitional forms, compared with the slow development of the type of the species, so that the gaps in palaeontology, which Darwin finds disturbing, are necessary here. Ditto the fixity of the species, once established, which is explained as a necessary law (apart from individual, etc., variations). Here hybridisation, which raises problems for Darwin, on the contrary supports the system, as it is shown that a species is in fact first established as soon as crossing with others ceases to produce offspring or to be possible, etc. In its historical and political applications far more significant and pregnant than Darwin."

Engels replies to Marx on the 2rd October 1866 leaving no doubt as to his differing opinion of Trémaux’s book:

"I have come to the conclusion that there is nothing to his whole theory because he knows nothing of geology, and is incapable of even the most common-or-garden literary-historical critique. That stuff about the nigger Santa Maria and the whites turning into Negroes is enough to make one die of laughing.......The book is utterly worthless, pure theorising in defiance of all the facts, and for each piece of evidence it cites it should itself first provide evidence in turn."

Letter 9. Marx to Engels; 3rd October 1866. Apparently undeterred by Engels’ view of Trémaux’s book being “worthless”, Marx further discusses Trémaux in a letter to Engels and, again, he shows that he is less than enamoured with Darwin:

"Your verdict that there is nothing to his whole theory because he knows nothing of geology, and is incapable of even the most common-or-garden literary historical critique recurs almost word for word in Cuvier’s ‘Discours sur les Révolutions du Globe in his attack on the doctrine of the variabilité des especes, in which he makes fun of German nature-worshippers, among others, who formulated Darwin’s basic idea in its entirety, however far they were from being able to prove it."

He further states that Trémaux’s work is:

".......an idea which needs only to be formulated to acquire permanent scientific status."

Letter 10. Engels to Marx; 5th October 1866. Although Engels starts by giving Darwin faint praise, he chides both Darwin and Trémaux for not identifying a mechanism for heredity:

"In one respect, Darwin is also right in his views on the effect crossing has in producing change, as Trémaux incidentally tacitly acknowledges.......Similarly, Darwin and others have never failed to appreciate the effect of the soil, and if they did not especially emphasise it, this was because they had no notion of how the soil exerts an influence — other than that fertility has a favourable and infertility an unfavourable effect. And Trémaux is little the wiser about that either."

Letter 11. Marx to German gynaecologist Ludwig Kugelmann; 9th October 1866. Four days later, despite Engels’ continuing poor opinion, we find Marx again championing Trémaux, reiterating his opinion that Trémaux’s work is superior to that of Darwin:

"I would also recommend to you Trémaux: ‘De 1’origine de tous les êtres, etc.’ Although written in a slovenly way, full of geological howlers and seriously deficient in literary-historical criticism, it represents — with all that, and all that — an advance over Darwin."

Marx’s enthusiasm for Trémaux’s ideas seems based on their shared notion that human beings are physiologically fundamentally malleable and not unduly constrained by any mechanisms of heritability. If so, this allows us another insight into his poor understanding of Darwin’s scientific findings in particular, and biology in general. Trémaux’s basic hypothesis was eccentric, even for his day. He suggested the chemical composition of the soil determined physiological and psychological traits, including cultural and even national characteristics. Soil formed during later geological periods was deemed to be more chemically complex and was thus responsible for more complex, higher civilisations than soil formed at earlier times. Engels, who had always demonstrated a superior understanding of the natural sciences relative to Marx, was better able to identify the numerous flaws and shoddy evidence used in support of Trémaux’s argument. Marx, however, considered Trémaux, despite his "geological howlers" (again echoing Engels) to be "a very significant advance over Darwin" and capable of achieving "permanent scientific status" with some tweaks to his hypothesis. Only someone who did not appreciate the scientific strength of Darwin’s theory could possibly be capable of such a ‘howler’ themselves.  Engels never mentioned Trémaux in any of his published work and unsurprisingly, Trémaux’s work never achieved the status Marx wished for it and it soon disappeared from the scientific mind.

Letter 12. Marx to Engels; 7th December 1867. This letter comes more than a year later. Marx appears to be responding to an article in ‘Der Beobachter’ (‘The Observer’) newspaper by the editor Karl Mayer, who Marx clearly dislikes. Regarding Darwin, his comment is wholly inconsequential:

"Now as regards the tendency of the author, another distinction has to be drawn. When he demonstrates that present society, economically considered, is pregnant with a new, higher form, he is only showing in the social context the same gradual process of evolution that Darwin has demonstrated in natural history."

Letter 13. Marx to Engels; 25th March 1868. A similarly inconsequential mention of Darwin, three months later. The comment concerns the ideas of the German agronomist Karl Nikolaus Fraas:

"Very interesting is the book by Fraas (1847): Klima und Pflanzenwelt in der Zeit, eine Geschichte beider, namely as proving that climate and flora change in historical times. He is a Darwinist before Darwin, and admits even the species developing in historical times."

Marx continues to discuss Fraas and clearly admires him intellectually, despite labelling him "a bourgeois."

Letter 14. Engels to Marx; 22nd Oct 1868. Seven months later, Engels informs Marx that he has read Darwin’s latest book, ‘The Variation of Animals and Plants under Domestication’ (1868). His dismissal of the work is particularly succinct:

"I’ve read Darwin’s first volume on DOMESTICATION. Only details are new, and then not much of importance."

This was to be Engels’ last mention of Darwin in his private correspondence for seven years.

Letter 15. Marx to Engels; 14th November 1868. Marx makes a sarcastic remark regarding Ludwig Büchner and is dismissive of his recently published 'Sechs Vorlesungen’ (1868; ‘Six Lectures on Darwinian Theory’), accusing him of plagiarism:

"The great Büchner has sent me his 'Sechs Vorlesungen etc. über die Darwin'sche Theorie, etc'…………..Büchner, for instance (as everybody who has read Lange's balderdash knows anyway), states that his CHAPTER on materialist philosophy has been copied mainly from this very Lange."

In terms of evolutionary theory, there was little in the six lectures that Marx would have disagreed with. Büchner praised Darwin for reintroducing a philosophical element into biology and considered Darwin’s greatest contribution to science to be as a defeater of teleology, rather than the discoverer of natural selection. Marx’s dislike of Büchner seems to have rested on his attempt to meld evolutionary theory with socialism (as did Lange) as well having some personal basis. Büchner, however, had the last word; his ‘Six Lectures’ were expanded and reprinted after Marx’s death into a book-length work ‘Darwinismus und Sozialismus’ (1894).

Letter 16. Marx to Engels; 18th November 1868. Seven days later, we see Marx again insulting Büchner:

"Büchner’s clumsy work is of interest to me in as much as it quotes most of the German research in the field of Darwinism — Prof. Jäger (Vienna) and Prof. Haeckel.......The conscientiousness with which Büchner has acquainted himself with the English stuff is also shown by the fact that he classifies Owen as one of Darwin’s supporters."

There is some irony in this letter. Marx sarcastically (but fairly) comments on Büchner’s "conscientiousness"  for being seemingly unaware that there was (famously) ill feeling between the biologist and palaeontologist Richard Owen and Darwin, though they were formerly better disposed to each other. Briefly, Owen accepted biological evolution but not Darwin’s theory of natural selection, which he considered too simplistic. However, Marx is less than conscientious himself, appearing to think that the German anatomist Ernst Haeckel was a Darwinian. Certainly, Haeckel accepted biological evolution and he had great respect for Darwin, visiting him at home and sometimes showing more than a hint of sycophancy in his correspondence to him. His recently published book ‘Natürliche Schöpfungsgeschichte’ (1868; ‘The Natural History of Creation’), was marketed in Germany as an attempt to explain Darwin’s ideas to the general public. It was not an accurate description of its content, nor of Haeckel's career. Although often painted as the man who did more than anyone else to promote the work of Charles Darwin in Germany, Haeckel’s views on biology in general and on human origins in particular can be considered no more than semi-Darwinian. By his own admission, Haeckel’s view of evolution was far more Lamarckian than Darwinian.
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To be considered a Darwinian in 1868 required, at a minimum, acceptance of Darwin’s claim that natural selection was the primary mechanism that drove evolution. Haeckel only partly accepted this. Haeckel was also a strong advocate of eugenics, something Darwin did not support. Two years earlier, when biologist and anthropologist Thomas Huxley edited the English translation of Haeckel's book 'Generelle Morphologie' (1866) he removed, at Darwin's request (being ever the gentleman; and with Haeckel's agreement), large segments containing Haeckel's grossly acidic views on others who had contributed to the field of Darwinian evolutionary theory and with whom he disagreed (Uschmann, 1979). In the end, the book was reduced to less than half its size and was never published in that form. Nyhart (1994) has also discussed the distinct differences in direction that Darwin's and Haeckel's work took in the decades following publication of 'Origin of Species'. As Gasman (1971) reminds us:

"Haeckel's Darwinism is a vast transformation of what Darwin wrote and stood for."

By labelling Haeckel a Darwinian, therefore, Marx again demonstrates that he doesn’t understand Darwin’s theory as well as he thinks.

Letter 17. Marx to Ludwig Kugelmann; 5th December 1868. Two weeks later. Marx again makes no secret of his disdain for Büchner and yet another charge of plagiarism is made:

"I have received Büchner’s lectures on Darwinism. He is obviously a ‘book-maker’ and probably for this reason is called ‘Büchner’. His superficial babble about the history of materialism is obviously copied from Lange."

He also labels Büchner’s attempt to link his ideas with Darwin’s as "shallow nonsense."

Letter 18. Marx to Engels; 23rd Jan 1869. A very mundane mention of Darwin and yet another opportunity for Marx to disrespect Büchner:

"She [Marx’s eldest daughter Jenny] asks for the return of Büchner, since she has studied Darwin and now wishes to get acquainted with the great."

Letter 19. Marx to Paul and Laura Lafargue; 15th February 1869. Three weeks later Marx re-aims his derision away from Büchner and toward Darwin by way of Clémence Royer, the first French translator of ‘On the Origin of Species’. Royer, unbeknownst to Darwin, had written her own preface to the book where she had suggested the benefits of applying natural selection to human beings, though what she meant was the application of artificial selection and specifically negative eugenics, something Darwin found obnoxious. Marx had read Royer’s preface (he was fluent in French) but his response indicates that he does not seem to understand the difference between natural and artificial selection.

As for Darwin, he did not know Royer. His French publisher commissioned her because she had previous experience translating the work of biologists and Darwin’s preferred translator (who he knew personally) had declined due to the scientific nature of the book. We know from Darwin’s personal correspondence that he was both nonplussed and highly displeased with Royer’s actions. Writing to the American botanist Asa Gray on 10th June 1862 he vented his spleen in his characteristic gentlemanly fashion (in contrast to Marx and Engels’ sometimes less than gentlemanly tone):

"I received 2 or 3 days ago a French Translation of the Origin by a Madelle. Royer, who must be one of the cleverest & oddest women in Europe: [she] is [an] ardent Deist & hates Christianity, & declares that natural selection & the struggle for life will explain all morality, nature of man, politics &c &c!!!"

She likely was one of the cleverest women in Europe at the time, for in 1870 she became the first woman elected to a French scientific society, as a member of the Parisian Society of Anthropology. In other correspondence (to the French biologist Jean Louis Armand de Quatrefages de Bréau; 11th July 1862), Darwin writes:

"I wish the translator had known more of Natural History; she must be a clever, but singular lady.......”

And to the botanist Joseph Dalton Hooker (11th September 1862):

"Almost everywhere in Origin, when I express great doubt, she appends a note explaining the difficulty or saying that there is none whatever!! It is really curious to know what conceited people there are in the world."

Darwin remained unhappy with the French version until Edmond Barbier’s translation for the third French edition in 1876.

A few weeks before Marx’s letter, Paul Lafargue had unsuccessfully attempted to commission Royer to translate ‘Das Kapital’ into French. Marx and Lafargue would likely not have been aware of the controversy regarding the preface and Darwin’s criticism of Royer. Marx probably assumed, given his previous incorrect assumptions about Darwin’s theory, that Darwin was in full agreement with Royer’s preface, leading to his criticism of her as "bourgeois" (echoing, of course, Engels’ view of Darwin as "bourgeois", being the standard criticism of anyone Marx and Engels disagreed with). As it turned out, a complete French translation of Marx’s book was not available until six years later, having been published in instalments from 1872-1875. Even then, Marx was unhappy with parts of Joseph Roy’s translation, describing it as "too literal" and so felt compelled to re-write numerous passages in French himself.

In this letter note Marx’s unambiguous criticism of Darwin’s theory, even though it seems he still does not properly understand it. His use of the term "The Darwinism" refers to what we now would label ‘social Darwinism’:

"As to Paul’s lively narration of his adventure with Mlle Royer, it has tickled Engels and my humble self. I was not at all astonished at his failure. He will remember that, having read her preface to Darwin, I told him at once she was a bourgeois. Darwin was led by the struggle for life in English society — the competition of all with all, bellum omnium contra omnes — to discover competition as the ruling law of ‘bestial’ and vegetative life. The Darwinism, conversely, considers this a conclusive reason for human society never to emancipate itself from its bestiality."

Letter 20. Marx to Engels; 10th February 1870. One year on Marx writes to Engels and briefly discusses the political scene in Paris. Gustav Flourens has fled the country three days earlier after failing to overthrow the government. His father was the well-known physiologist Marie Jean Pierre Flourens, an ardent anti-Darwinian creationist. The “nearly 100 years of life” comment is an exaggeration by Marx, as he lived only 73 years:

"Flourens, the CRACK-BRAINED youngster, is the son OF LATE Flourens, secrétaire perpétuel de l'Académie, who always adhered to the existing government throughout his nearly 100 years of life, and who was, in turn, Bonapartist, legitimist, Orleanist and again Bonapartist. During the last years of his life he still made himself noticeable with his fanaticism against Darwin."

Letter 21. Marx to Engels; 14th April 1870. This mention comes, not in the main text of the letter, but in the postscript. Darwin is mentioned only in passing. Note, however, the derogatory reference to Thomas Huxley’s philosophical views:

“Apropos. Stirling [J. H. Stirling, The Secret of Hegel: Being the Hegelian System in Origin, Principle, Form, and Matter] (Edinburgh), the translator of Hegel’s Logic, and heading the British subscription for the Hegel monument — has written a small pamphlet against Huxley and his protoplasm. As a Scotsman, the fellow has naturally adopted Hegel’s false religion and Idealistic mysticism (so induced Carlyle to declare publicly his conversion to Hegelianism). But his knowledge of Hegel’s dialectic allows him to demonstrate Huxley’s weaknesses — where he indulges in philosophising. His business in the same pamphlet against Darwin comes to the same as what the Berliner Blutschulze Hegelian of the old school) said some years ago at the natural scientists’ meeting in Hanover."

Marx and Engels never really warmed to Huxley though they seem to appear to have accepted him as a competent scientist. In late 1862 Marx attended a series of six public lectures on Darwin’s findings given by Huxley, along with his friends Friedrich Lessner and Liebknecht (1896; "we attended conscientiously"). Yet Huxley appears to have had zero effect on Marx’s political philosophy. ‘Darwin’s Bulldog’ shares much the same fate as Darwin himself, in terms of sparse mentions in Marx and Engels’ published work. For example, he gets only a single mention in Volume 1 of ‘Das Kapital’. This is in a footnote concerned solely with the lung capacity of the "healthy average individual" and their production of carbonic acid. Huxley is ignored in Volumes 2, 3 and 4. For Engels, while ‘On the Origin of Species’ was "epoch-making", Huxley’s (1863) book on human origins was “very interesting and quite good" (Engels to Marx, 8th April 1863). The private correspondence of Marx and Engels reveals only two other occasions in which Huxley is mentioned; one letter from Marx to Engels (28th January 1863) which states no more than Huxley had recently lectured at the Institute of Geology in Jermyn Street. The second comes 32 years later (Engels to the sociologist Ferdinand Tönnies; 24th January 1895) in which Engels criticises the philosopher Augustine Comte’s insistence in the importance of maintaining hierarchy in social structures, relating that:

"Huxley could say of Comtism that it was Catholicism without Christianity."

Engels quotes Huxley directly, once only, in ‘Dialectics of Nature’ (1883a). Not for any purpose of political philosophy, but rather to share in ridiculing the then popular craze of spiritualism. Huxley was declining an invitation to join a committee of the London Dialectical Society investigating "phenomena alleged to be spiritual manifestations":

"The only good that I can see in the demonstration of the truth of `spiritualism' is to furnish an additional argument against suicide. Better live a crossing-sweeper than die and be made to talk twaddle by a `medium' hired at a guinea a séance!"

This distinct lack of enthusiasm for just about anything Huxley had to say was probably not based on his scientific views but rather his perennial philosophical stance. Huxley was perfectly happy to accept materialism in the methodological sense, when conducting science, however, although he is often portrayed as otherwise, Huxley was undoubtedly strongly anti-materialist in an ontological sense, evidenced by this statement given in his 1868 lecture 'On the Physical Basis of Life’ (and published 1869):

"I, individually, am no materialist, but, on the contrary, believe materialism to involve grave philosophical error."

Letter 22. Marx to Ludwig Kugelmann; 27th June 1870. Two months later Marx is discussing the book ‘On the Worker’s Question’ by the German philosopher, Friedrich Lange who had attempted to amalgamate Marxist philosophy and Darwin’s scientific findings into a movement he labelled ‘socialist Darwinism’ (not to be confused with ‘social Darwinism’). In particular, he proposed that Darwin’s ‘struggle for existence’ was a natural law that applied no less to human beings than to the rest of the natural world. Both Marx and Engels were distinctly unimpressed and treated Lange with outright disdain and scorn (see e.g., Ball, 1979; Stack, 2000; 2003), and he was predictably labelled as a "bourgeois Darwinian" by Engels. Marx’s letter acts a critique of Lange’s book and his opinion is unambiguous. He is sarcastic and dismissive:

"Mr Lange (On the workers’ question, etc., 2nd edition) pays me great compliments, but with the object of increasing his own importance. Mr Lange, you see, has made a great discovery. All history may be subsumed in one single great natural law. This natural law is the phrase (— the Darwinian expression becomes, in this application, just a phrase —) ‘struggle for life’, and the content of this phrase is the Malthusian law of population, or rather over-population. Thus, instead of analysing this ‘struggle for life’ as it manifests itself historically in various specific forms of society, all that need be done is to transpose every given struggle into the phrase ‘struggle for life’ and then this phrase into the Malthusian ‘population fantasy’. It must be admitted that this is a very rewarding method — for stilted, mock-scientific, highfaluting ignorance and intellectual laziness."

Darwin was as unenthused as Marx and Engels were with Lange’s attempt at melding his scientific findings with Marxism. To the Austrian diplomat and explorer Karl von Scherzer on 26th December 1879 he wrote:

"What foolish idea seems to prevail in Germany on the connection between Socialism and Evolution through Natural Selection."

Letter 23. Engels to Russian philosopher Pyotr Lavrov; 24th September 1875. Lavrov was an exponent of ‘scientific socialism’, which also embraced Darwinian evolutionary theory. Engels is replying to Lavrov’s letter dated 20th August, which he had only just received as he was on holiday. He tells Lavrov that he intends to read his article, recently published in the Russian journal ‘Vperyod!’ (‘Forward!’):

".......so as to be able to tell you where we agree and where we differ in our views on the relationship of socialism to the struggle for existence as propounded by Darwin."

Letter 24. Engels to Pyotr Lavrov; 12-17th November 1875. Two months later and Engels has now read Lavrov’s article. In this lengthy letter (written in German, along with Russian, French and Latin sentences and phrases), he outlines his disagreement with Lavrov and expounds on the reasons as to why Darwin’s scientific findings cannot provide the basis for Marxist political philosophy. Much of this letter is included almost verbatim in Engels’ book ‘Dialectics of Nature’ (1883a). The most relevant portions of the letter text are reproduced here:

"1. Of Darwin's doctrine, I accept the theory of evolution, but assume Darwin's method of verification (STRUGGLE FOR LIFE, NATURAL SELECTION) to be merely a first, provisional, incomplete expression of a newly discovered fact. Before Darwin, the very people who now, wherever they look, see nothing but the struggle for existence (Vogt, Büchner, Moleschott and others), once laid particular stress on co-operation in organic nature, the way in which the plant kingdom supplies oxygen and food to the animal kingdom and, conversely, the latter supplies plants with carbonic acid and manure, as indicated notably by Liebig. Both conceptions are to some extent justified, but each is as one-sided and narrow as the other. The interaction of natural bodies—both dead and living—comprises harmony as well as strife, struggle as well as cooperation. Hence, if a self-styled naturalist takes it upon himself to subsume all the manifold wealth of historical development under the one-sided and meagre axiom 'struggle for existence', a phrase which, even in the field of nature, can only be accepted cum grano salis [with a grain of salt] his method damns itself from the outset."

There are two points to be made here. First, Engel’s use of the phrase "Darwin’s doctrine" is telling. This use of language is identical to that used modern creationists like Morris or Bergman. Painting Darwin’s work as a prescriptive doctrine rather than an explanatory model based on empirical findings is commonplace in the creationist literature and it is surprising to see someone reasonably well versed in the natural sciences using such fallacious semantics. The "one-sided" and "cum grano salis" jibes are also reminiscent of a creationist author. Arguably, it comes across as a cheap shot, which demeans Engels’ usual attempt at balance. Second, Engels is equating the ideas of Darwin and Spencer by overtly substituting Spencerian ideas for Darwinian concepts. As discussed, Spencer’s notion of the ‘survival of the fittest’ is vastly different to Darwin’s ‘struggle for existence’. The misrepresentation is made all the worse by the fact that several years earlier, Darwin had published a second seminal work, ‘The Descent of Man’ (1871), in which he discusses at some length the importance of cooperativity and sympathy in the evolution of the primate species in general, including humans.

"2. Of the three ubèzdennyie Darwinistyh [convinced Darwinians] you cite, only Hellwald would seem worthy of mention. After all, Seidlitz is at best no more than a minor luminary and Robert Byr a novelist, whose novel Drei Mal is currently appearing in Ueber Land und Meer. And that's where all his rodomontade belongs."

"3.......All that the Darwinian theory of the struggle for existence boils down to is an extrapolation from society to animate nature of Hobbes' theory of the bellum omnium contra omnes and of the bourgeois-economic theory of competition together with the Malthusian theory of population. Having accomplished this feat (the absolute admissibility of which, as indicated above under 1, I contest, especially where the Malthusian theory is concerned), these people proceed to re-extrapolate the same theories from organic nature to history, and then claim to have proved their validity as eternal laws of human society. The puerility of this procedure is self-evident, and there is no need to waste words on it. If, however, I did wish to enlarge upon it, I should represent them, firstly as bad economists and secondly as bad naturalists and philosophers."

Again, Engels appears to be portraying Darwin’s theory as Spencerian, not based on empirical evidence, but as bad philosophy.

"4. The essential distinction between human and animal society is that the most animals do is garner, whereas humans produce. This unique but crucial distinction alone makes it impossible simply to extrapolate the laws of animal societies to human societies. What it does make possible, as you rightly remark, is that celovëk vel borjbu ne toljko za suscestvovanie, no za naslazdenie i za uvelicenie svojich naslazdenij.......gotov byl dlja vyssago naslazdenija otrecsja ot nissich [man was not simply engaged in a struggle for existence but also for enjoyment and for the intensification of his enjoyment.......was prepared to forego less high for the sake of higher enjoyment]. While not contesting the conclusions you proceed to draw from this, I would, from my own premisses, draw the following inferences: At a certain stage, then, human production reaches such a level that not only necessary requirements are produced, but also luxuries if, to begin with, only for a minority. The struggle for existence—if, for the moment, this category be allowed—thus becomes a struggle for enjoyment, not just for the means of subsistence, but for the means of development—socially produced means of development—and in respect of this stage the categories of animal kingdom are no longer applicable. If, however, as has now happened, production in its capitalist form produces means of subsistence and development far in excess of what can be consumed by capitalist society since it keeps the great mass of real producers artificially at a distance from these means of subsistence and development; if, by its own existential law, that society is compelled continually to raise what is, for its own purposes, an already excessive production and hence periodically, every ten years, gets to the point of destroying, not only huge quantitites of products, but even the productive forces themselves— what meaning still attaches to talk of the 'struggle for existence'? For in that case the struggle for existence can consist only in this—that the producing class takes over the management of production and distribution from the class formerly entrusted with that task but now no longer capable of it, and this, in effect, is socialist revolution."

“I might remark en passant that the mere consideration of previous history as a series of class struggles is enough to reveal the utter shallowness of the view of that same history as a slightly modified representation of the 'struggle for existence'. Hence it's a favour I'd never do these bogus naturalists."

One might reasonably ask at this point how it is possible to digest Engels’ letter and be convinced that he (along with Marx) was a "doctrinaire evolutionist." And that "Marxism, socialism, and communism.......are squarely based on evolutionism"?

Letter 25. Engels to Marx; May 28th 1876. Six months later, Engels makes a passing disparaging remark about the German physicist Hermann von Helmholtz who was attempting a neo-Kantian view of human perception:

"Herr Helmholz has never stopped chasing round the ‘thing-in-itself’ since 1853 and has still not got clear about it. The man is not ashamed of calmly allowing the nonsense he had printed before Darwin to be still reprinted over again."

Letter 26. Marx to Engels; 11th December 1876. Another half year passes before we reach the next Darwin mention. It occurs in the (longer) postscript of a very brief letter. The context is a conference organised by the Liberal Party in London three days earlier dealing with the question of relations with Russia. Marx first repeats a claim that the "workers" taking part in a demonstration outside the hall "without exception belonged to a paid band" leading to:

"Unfortunately Charles Darwin also lent his name to the rotten demonstration."

Letter 27. Engels to the German zoologist Eduard Oscar Schmidt; 19th July 1878. More than 18 months later Engels writes to the Darwinian zoologist Oscar Schmidt. The 51st Congress of Natural Scientists and Physicians was coming up in September 1878 and the program included Schmidt’s paper entitled 'On the Relation of Darwinism to Social Democracy' in which he was going to propose an amalgamation of evolutionary theory and socialism. Engels was decidedly unimpressed. He issued  Schmidt with a warning that he intended to subject his paper to "ruthless criticism":

"By way of making a contribution of my own, I am taking the liberty of sending you by post a copy of my work Herr Eugen Duhring's etc., which has just come out. In it, I have endeavoured to give, among other things, an outline of the relation of scientific socialism to the propositions of modern theoretical natural science in general, and to Darwin's theory in particular. The passages relating to Darwinism are marked."

He goes on:

"With your permission, I shall in due course and from my own standpoint subject your lecture to the kind of ruthless criticism which alone does justice to free science and which any man of science must welcome, even when applied to himself."

Letter 28. Engels to Pyotr Lavrov; 10th August 1878. Engels starts by referring to a paper (‘The Freedom of Science in the Modern State’) presented at the previous 50th Congress of Natural Scientists and Physicians by German physician and pathologist Rudolf Virchow. Virchow was a maverick as a medical doctor being anti-evolution, anti-Darwinian theory, and refusing to accept the germ theory of disease. In his presentation, he had proposed that Darwinism should be banned in schools and that any amalgamation of Darwinism and socialism was morally dangerous and a threat to social order (though he himself was socially liberal). Engels writes:

"As you will have seen, the German Darwinians have, in response to Virchow's appeal, come out unequivocally against socialism."

He then reiterates his position re Eduard Oscar Schmidt:

"Mr Oscar Schmidt of Strasbourg is going to flatter us [i.e., socialists] con amore at the natural scientists' conference in Kassel. It's a waste of effort. If reaction in Germany gets the bit between its teeth, its first victims, after the socialists, will be the Darwinians."

Letter 29. Engels to the German Marxist theorist Eduard Bernstein; 3rd May 1882. We need to jump almost four years for this next transitory mention of Darwin. It concerns Darwin’s reply to Marx nine years earlier (1st October 1873) discussed earlier following Marx’s gift of ‘Das Kapital’. The following sentence occurs alone, unconnected to other subjects discussed in the letter:

"Darwin's letter was of course addressed to Marx and was an extremely kind one."

Letter 30. Marx to Engels; 5th June 1882. Marx writes this letter in Cannes, France where he is unwell with a bronchial condition and the letter is solely about this subject and the expert medical attention he is receiving. The mention of Darwin is jovial yet mundane, to say the least:

"Nature, too, can evince a certain philistine humour (after the manner, already humorously anticipated in the Old Testament, of the serpent feeding on dust, cf. the dusty diet of Darwin's worms)."

Here, Marx is alluding to two Old Testament passages as well as Darwin’s most recent book ‘The Formation of Vegetable Mould, through the Action of Worms, with Observations on Their Habits’ (1881; his bestselling book during his lifetime) in which he revealed that worms eating soil and defecating it aids in the formation of humus.

Letter 31. Marx to Engels; 4th September 1882. Marx is still in France. The following is the final sentence of the letter and appears unaccompanied by any other relevant discussion.

"Mr Virchow, or so I see from the supplément to yesterday's Journal de Genève, has again demonstrated that he is far and away above Darwin, he alone, in fact, being scientific and hence also 'contemptuous' of organic chemistry."

This is more an unmistakeable sarcasm aimed at Rudolph Virchow, less a favourable comment on Darwin. This was the last letter Marx wrote in which he mentioned Darwin. He died a little over six months later.

Letter 32. Engels to the Czech-Austrian socialist philosopher Karl Kautsky; 15th November 1882. This is the first of three letters spanning a little more than two year period in which Engels mentions Darwin, all three being addressed to Karl Kautsky. At the time Kautsky was arranging publication in Stuttgart of a new socialist journal ‘Die Neue Zeit’ (‘The New Times’; published 1883-1917) and had asked Engels to contribute an article on Darwin. He replies:

"The Darwin article in particular is an impossibility just now.......To dash off a few commonplaces on Darwin would serve neither you nor me."

Letter 33. Engels to Kautsky; 10th February 1883. Engels refers to an article authored by Kautsky entitled 'Hetärismus' (1882-1883: ‘Hetaerism’) that had been recently published in the journal ‘Kosmos: Zeitschrift für Entwickelungslehre und einheitliche Weltanschauung’ (‘Kosmos: Magazine for Development Theory and Unified Worldview’). This was the first article by Kautsky in a series of three, under the umbrella title ‘Die Entstehung der Ehe und Familie’ (1882-1883; On the Emergence of Marriage and Family). Hetaerism is a stage of proto-human society originally hypothesised by the Swiss anthropologist Johann Jakob Bachofen in 1861 and expanded upon by the Darwinian sociologist Lewis Morgan in his book ‘Ancient Society’ (1877). In this stage, families did not exist. Instead, polyamory was practiced and women, like land, were considered common property. As a result, children would have no relationship with a single father and descent was known only through the matrilineal line. The subject was pertinent to Engels at that time because the following year he published ‘The Origin of the Family, Private Property and the State’ from which he drew much from Bachofen and Morgan (though Kautsky’s srticle is not mentioned). Ten years later this was to become the first book by Engels published in Russia, and Lenin later described it as "one of the fundamental works of modern socialism."

Engels (1884) agreed with Bachofen, Morgan and Kautsky that such a shift occurred in proto-human and early human societies (though he disliked the term hetaerism) from communal mating to pairing but disagreed with the strength of the role played by biological laws. He accepted that this probably partly resulted from natural selection, because the clusters of nuclear families that resulted would have experienced strengthened familial and social ties. However, he strongly doubted that natural selection was the only mechanism, and disagreed that natural selection played any part at all in further social evolution. In his article, Kautsky had introduced evidence from anthropological studies of chimpanzees and other primate communities but Engels was not convinced and yet again, there is a dig at Darwin for having taken Malthus seriously:

"Darwin is no more of an authority in this field than in that of political economy, whence he imported his Malthusianism."

Engels does go on make some salient methodological points against Kausky’s evidence, however:

"We know practically nothing about apes in this respect, since observations in a menagerie prove nothing and are difficult to make in the case of a troop of wild apes, while such as are alleged to have been made cannot claim to be accurate, conclusive or even universally valid. Gorillas and orang-outangs must in any case be excluded, since they do not live in troops."

Letter 34. Engels to Kautsky; 16th February 1884. A year later and Engels is recommending Morgan’s 1877 book to Kautsky:

"There is a definitive book — as definitive as Darwin's was in the case of biology - on the primitive state of society; once again, of course, Marx was the one to discover it. It is Morgan's Ancient Society, 1877."

Later in the letter, Engels once again displays disdain for those who attempt Darwinian incursions into human social and cultural evolution:

"All the impostures - endogamy, exogamy and whatever else the balderdash is called - of Tylor, Lubbock and Co. have been demolished once and for all."

Edward Tylor was an English anthropologist, considered the originator of cultural anthropology with his two-volume 1871 book ‘Primitive Culture’. He strongly supported biological evolution. John Lubbock was a wealthy Englishman who contributed to science as an amateur biologist and archaeologist. He coined the terms ‘paleolithic’ and ‘neolithic’. Also a strong supporter of evolutionary theory, he was a close friend of Darwin for many years. Engels’ criticisms of Tylor and Lubbock were also included in the first German language edition of his book ‘The Origin of the Family, Private Property and the State’ (1884).

Letter 35. Engels to Paul Lafargue; 10th May 1884. The relevant text here is this:

"Your lectures and those of Deville are excellent but, at least for the published version, you should develop more exhaustively the conclusions of your second one on Darwinism. That part seems overwhelmed by the mass of premisses leading up to the conclusion, nor is the latter self-evident enough, while its detail is inadequately developed."

Engels is referring to a series of seven Sunday lectures on socialist politics, economics and philosophy, given by Lafargue and the socialist lawyer Gabriel Deville at the French Workers Party library. They were due to be published at the time of writing.

Letter 36. Engels to Laura Lafargue; 23rd November 1884. This is no more than a routine request for the return of loaned books, including ‘On the Origin of Species’:

"Now before concluding I want to ask you a favour. Paul has from me: 1 ) Darwin's Origin of Species, 2) Thierry, Histoire du tiers état, 3) Paquet, Institutions provinciales et communales de la France, 4) Buonarotti, Conspiracy of Babeuf . Now, Jenny had from me: 1) Die 'Edda'', poetische und prosaische, and 2) Beowulf, both in Simrock's New High German translation. The latter two books and Darwin I am in especial want of. Could you get them together if they can be found…."

Letter 37. Engels to the economist Nikolai Danielson; 15th October 1888. This mention is no more than a report that the German economist Lujo Brentano advocated using empirical rather than philosophical methods in social research. Engels mentions Darwin only in the context of being a successful scientist (along with three other examples):

"To prove to you to what depths of degradation economical science has fallen, Lujo Brentano has published a lecture on Die Klassische Nationalokonomie (Leipzig, 1888), in which he proclaims: general or theoretical economy is worth noting, but special or practical economy is everything. Like natural science (!), we must limit ourselves to the description of facts; such descriptions are of infinitely higher value than all a priori deductions. ‘Like natural science’! That is impayable in the century of Darwin, of Mayer, Joule and Clausius, of evolution and the transformation of energy!”

Note the exclamations after both uses of the term ‘natural science’. This, along with his comments in Letter 33 (Engels to Kautsky; 10th February 1883) surely make clear that Engels did not view the entirety of Darwin’s evolutionary theory as being empirically based. This was the last mention of Darwin in Engels’ personal correspondence for almost six years.

Letter 38. Engels to Kautsky; 23rd September 1894. The final mention of Darwin is in a discussion of Enrico Ferri’s book ‘Socialismo Escienza Positiva (Socialism & Positive Science; 1894). Ferri draws comparisons between socialism and Darwinism, and suggests that Darwin’s scientific findings offer a scientific basis for socialist principles. He also criticises those who point out the obvious contradictions. Engels gives his short and sharp, no-nonsense opinion of Ferri’s synopsis:

"His book on Darwin-Spencer-Marx is an atrocious hotchpotch of insipid rubbish."