Wednesday, November 16, 2011

Cognition and History: The Evolution of Intelligence and Culture

A brilliant address on the part played by intelligence in its own evolution:
The inaugural Science and Society Lecture; Amsterdam, 24 October 1996
by Henry Plotkin; Department of Psychology; University College London

The Causal Force of History

It will come as no surprise to social historians that history matters, to use S.J.Gould's phrase (Gould, 1986). However, this has not always been a universally accepted position in science. Two examples of how causes are framed in science will illustrate different approaches to the issue of history as having causal force. The first is that of the Russian chemist Mendeleev who invented in the middle of the last century the Periodic Table of the elements, building on Dalton's earlier proposal that each element has a characteristic atomic weight.
The Periodic Table was a brilliant insight, being based on Mendeleev's understanding that atoms have an internal structure. It is this structure that causes elements to have the properties upon which Mendeleev ordered the elements in his Table; and it is this structure that enabled him correctly to predict the existence of elements, and their properties, not then known. When later they were discovered, the Periodic Table and the theory underpinning it was vindicated and Mendeleev's fame was ensured. Now the point is this. The Periodic Table, a fabulously successful scientific insight, was based on the assumption that the laws of chemistry are absolutely constant and have always held. Had Mendeleev lived and worked 4.5 thousand million years ago, when the Solar System formed, he could have used the same observations and insights then to construct the Periodic table as he did in the 19th century. For example, since the beginning of time on this planet, when the elements sodium and chlorine have been mixed together they have formed a compound, table salt, which has rather different properties from those of its constituent elements.
This accords with the principles upon which the Periodic table was constructed and as a 19th century chemist, Mendeleev assumed not just that observations that he made of table salt on Monday would be the same on Tuesday and Wednesday, but that he could have made the same observations and drawn the same scientific insights thousands of millions of years ago. He was correct in this, but the general conclusion that was drawn that there is no temporal element to the laws of chemistry, that time in the form of historical antecedence does not have causal force, we now have reason to doubt.
Our second example comes from Darwin, who learned from 19th century geologists another way of thinking about causation. When Darwin visited the Galapagos Islands he observed over a dozen different species of finch, sometimes unique to different islands in the group and each distinctive, especially in their beaks and feeding behaviour. He concluded that these different species were all descended from a single mainland species, individual members of which had sometime in the past found their way to one of the islands, the descendent species resulting from the gradual migration of birds to other islands and the relative isolation of the islands from one another. This explanation of Darwin's finches was just one case, one illustration, of Darwin's wider thesis which asserts that all living things are related because all of life forms a tree-like structure that is descended from a common origin. 
Darwin's theory included an exposition of the processes that drive evolution, and these processes have the same quality of apparent timelessness as does atomic structure; whenever and wherever evolution occurs, these processes must be present. But the nature of causal explanation of Darwinian theory embraces historical antecedence as cause, and hence is very different from that espoused by Medeleev. In order to understand why a finch has this beak shape now, today, one has to invoke not only those universal and timeless processes of variation, selection and the transmission of selected variants, but also the form of beak that these processes acted upon in the past, yesterday...