By Gary Cziko
The first explanation for the adapted complexity manifested in the structure and behavior of living organisms was that it was the product of supernatural creator. According to the 18th- century natural theologist Reverend William Paley (1813), it was God who _provided_ every remarkable contrivance of the living world for the very purpose for which it is seen to be fit.
French biologist Jean-Baptiste Lamarck (1809) proposed a natural explanation for the functional complexity of the living world in which an organism's environment would cause adaptive changes and such acquired changes would be passed on to the organism's offspring. Lamarck's theory of biological evolution is an _instructionist_ theory in that the environment in effect instructs the required organismic adaptations.
Neither providential nor instructionist theories of the origin of adaptive change are given much serious consideration today in biology. Instead, the theory of natural selection proposed by Charles Darwin in 1859 remains the only widely accepted explanation for adaptive evolutionary change. The elegance and scientific appeal of Darwin's theory is that it shows how the nonpurposive and ignorant processes of blind variation and _selection_ can account for the remarkable adapted complexity that we see everywhere in the living world.
But the evolution of theories from providential through instructionist to selectionist is not limited to biological evolution. The first theory to attempt to explain the fit of antibody to antigen was Ehrlich's (1900) side-chain theory which assumed that all the information required for the construction of antibodies was _provided_ by the genome. Then the template theory of antibody construction of Breinl and Haurowitz (1930) and Pauling (1940) saw the antigen serving as a sort of instructionist cookie cutter for making antibodies. It is now known that the immune system is able to generate remarkably fit antibodies via the process of blind variation and _selection_, very much analogous to Darwin's selectionist theory of adaptive biological evolution.
This paper will present evidence that the transition from providential through instructionist to selectionist theories of the emergence of adapted complexity has occurred and is currently occurring in many fields of inquiry. These fields include epistemology, ethology, neuroscience, psychology, anthropology, linguistics, and education. In addition, the power of selection is now being exploited in computer science as well as in the design of organisms and molecules.
Finally, an argument will be made for Universal Selection Theory, the bold speculation that _all_ instances of adapted complexity-- from the design of a duck's foot to the usefulness of a scientific theory--are the result of a process of blind variation and selection.
The examples and arguments of this paper are extracted from Without Miracles: Universal Selection and the Second Darwinian Evolution, (MIT Press, 1995). [As the present abstract will not be developed into a full paper, other papers can refer to the book, FH].