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Science and Knowledge

Philosophers of science have used “evolution” for the growth of knowledge in two ways: for the evolution of the capacities that let organisms know anything at all, and for the development of theories and concepts as a process of variation and selection in its own right. The second is the subject here, and its authors carry very different amounts of the Darwinian apparatus.

Popper’s natural selection of hypotheses

Karl Popper’s Objective Knowledge: An Evolutionary Approach (1972) described the growth of knowledge as “the result of a process closely resembling what Darwin called ‘natural selection’; that is, the natural selection of hypotheses”. Conjectures are the variants and criticism and testing the selection; “from the amoeba to Einstein, the growth of knowledge is always the same”, with the difference that the amoeba perishes with its mistaken theory while a scientist can discard the theory and survive. In “Natural Selection and the Emergence of Mind” (1978) he put it in one line: “Let our conjectures, our theories, die in our stead!”

Donald T. Campbell had stated the scheme in general form in 1960: any process that produces fit between a system and its environment needs a source of variation, a consistent selection and a means of retaining what is selected, and the variation must be blind in the sense of not being produced with foreknowledge of what will succeed. His essay for the volume on Popper in the Library of Living Philosophers (1974) named the programme evolutionary epistemology and set out a nested hierarchy of knowledge processes, from trial-and-error locomotion through habit, instinct, thought, imitation and language to science, each level a shortcut that selects vicariously on behalf of the level below. Popper’s method was the top of the hierarchy.

Toulmin’s populations of concepts

Stephen Toulmin’s Human Understanding (1972) treated a scientific discipline as a population of concepts that changes over time as variants are proposed and some are taken up, in an “intellectual ecology” that sets what counts as success. The unit was the concept rather than the theory, and the standards of rationality were themselves local to the discipline and subject to the same change.

Kuhn’s closing analogy

Thomas Kuhn ended The Structure of Scientific Revolutions (1962) with Darwin. The resolution of revolutions is “the selection by conflict within the scientific community of the fittest way to practice future science”, and scientific development “is a process of evolution from primitive beginnings” but “not a process of evolution toward anything”. The analogy was meant to answer the charge that a science without a goal of truth could not progress: Darwin had shown how directed-looking change could come about with no goal set in advance. Kuhn also warned that “the analogy that relates the evolution of organisms to the evolution of scientific ideas can easily be pushed too far”, and he pulled back from it when critics pressed it.

Hull’s selection process

David Hull’s Science as a Process (1988) carried the fullest apparatus into the case. Using the distinction between replicators, which pass on their structure, and interactors, whose interaction with the environment makes replication differential, he argued that scientific ideas are replicated through publication and teaching and that scientists and research groups are the interactors, competing for credit in a system that rewards the use of one’s ideas by others. His evidence was a participant-observer’s history of the cladistics dispute in systematics.

Two programmes

The literature distinguishes the evolution of cognitive mechanisms, the account of how the capacities for perceiving and reasoning were shaped by natural selection, from an evolutionary account of theories, in Michael Bradie’s terms, and holds that the two can succeed or fail independently. The first reaches back to Konrad Lorenz’s reading of Kant’s a priori as what the species learned a posteriori; the second is the line of Popper, Campbell, Toulmin and Hull. Its standing objection is to the blindness of the variation. Paul Thagard’s “Against Evolutionary Epistemology” (1980) argued that scientists generate hypotheses by reasoning aimed at the problem, so that variation in science is guided rather than blind, and that selection among theories works by criteria of evaluation that have no counterpart in natural selection. Campbell’s answer, in the vicarious selectors of 1974, was that guidance is itself the product of earlier selection; Dean Keith Simonton, defending the model since, has treated blindness as a matter of degree rather than an all-or-nothing condition.

See also: Evolution (the subject landing) · The criterion · Philosophy of science · Popper · Campbell · Kuhn · Hull · Cultural extensions of Darwinism