Quote: Dart on Piltdown and ape relationships

I was flipping through a 1929 paper by Raymond Dart, “A note on the Taungs skull”, in the South African Journal of Science. In this, Dart gives a scientific overview of some of his thinking about human origins in light of his discovery. Most of this, in retrospect, was wrong, and in fact I was looking through this to cite some of Dart’s assumptions about climbing and terrestriality in Australopithecus which have turned out to be erroneous.

In the process, I was struck by one paragraph. It gives a very tight overview of why Dart assumed that the human lineage must have become separate from apes at a very early date, much earlier than the diversification of today’s great apes.

Now it is a very important matter that man, especially a primitive man (like Piltdown man) has many features in which he is related, not only to the gorilla and chimpanzee on the one hand, hut also to the orang on the other. We know from this that the human stock was derived from the ape stock at a remote period, that is, before the chimpanzee and orang had left the main stem, in other words, while the capacity for giving rise to chimpanzoid and orangoid features were both inherent in the common human-ape stock. When we find man is a mixture and has characters linking him to two such widely divergent apes as the chimpanzee and orang, we say that man arose from a generalised, and not a specialised ape stock. We know that man's true ape ancestor must be still more generalised, still more of a mixture than the most primitive of men known, that this ancestor will be still more of a mixture, as it were, between the chimpanzee and the orang. (I do not refer particularly to the gorilla because it is more specialised and more different anatomically from man than the chimpanzee, and, therefore, further removed from the human stock, and also because the chimpanzee is sufficiently representative of the specialisations which we find in its near cousin, the gorilla.) Man's ape ancestor must, therefore, be an ape intermediate in character between the divergent chimpanzee and orang, but must be sufficiently advanced in its features towards those qualitative anatomical characters which are strictly human to justify the expectation that it would, with further evolutionary development, give origin to the earliest known types of human being such as Pithecanthropus, the ape-man of Java, and Eoanthropus, the Dawn-man of England.

This, in light of a century of evidence, was also wrong. But Dart’s reason for being wrong here is his reliance upon the Piltdown evidence. One might say he was wrong for reasons that seemed eminently logical.

Piltdown had orangutan-like features because its jaw was an orangutan jaw.

Humans and fossil hominins, we know today, are closer to chimpanzees and gorillas than any of them are to orangutans. Yet anthropologists from the mid-nineteenth century onward tended to accept that the living great apes form a natural group, and that the human lineage diverged from this group at a very early period, as early as the Eocene.

Clearly the general anatomical distinctiveness of humans from the living great apes contributed the most to this perception of a deep split between them. Most anthropologists accepted this scenario long before the Piltdown hoax was perpetrated, and many continued to accept it long after the hoax was revealed.

Still, this little detail shows how a singular fossil can reinforce scientists’ thinking. A testament from the past that confirms their predispositions is likely to carry much weight in their description of evolution, even if the fossil did not contribute to the way they formed their hypotheses. It is valuable to be especially critical of findings that align with one’s own views.