Philosophy of Biology

HALDANE AND THE EMERGENCE OF

MODERN EVOLUTIONARY THEORY

Sahotra Sarkar

1 INTRODUCTION

This paper is about Haldane’s place in the development of evolutionary theory,

an attempt to assess his role in the so-called modern synthesis, but it also delves

into the more philosophical issue whether Waddington’s and Mayr’s well-known

critique of mathematical population genetics is credible.^1 It looks, in some detail,

at what Haldane achieved in the 1920s and early 1930s but ignores important

later contributions, in particular, his introduction of genetic load arguments.^2 The

paper is partly motivated by the fact that the two standard historical accounts of

the development of modern evolutionary theory pay little attention to Haldane.

The first, the “genetical” account, most systematically elaborated by Will Provine

[1971; 1985; 1986], sees the history as an epic struggle between Fisher and Wright

and their respective followers. In sharp contrast, the second “naturalist” account,

advocated since the late 1950s by Ernst Mayr, has both a negative and a positive

thesis. The negative thesis is the rejection of any important role for theoretical

population genetics. The positive thesis is an alternative reconstruction of the

history of twentieth-century evolutionary theory.

For instance, Mayr [1980, 1] inaugurated a conference on the history of the

so-called synthesis with the following remarks:

The term ‘evolutionary synthesis’ was introduced by Julian Huxley

inEvolution: The Modern Synthesis(1942) to designate the general

acceptance of two conclusions: gradual evolution can be explained in

terms of small genetic changes (‘mutation’) and recombination, and

the ordering of this genetic variation by recombination; and the ob-

served evolutionary phenomena, particularly macroevolutionary pro-

cesses and speciation, can be explained in a manner that is consistent

with the known genetic mechanisms. The objective of this conference

is to examine the rapid changes in evolutionary biology that occurred

in the period of the synthesis (from approximately 1936 to 1947).

(^1) Sarkar [2005] takes up the issue whether the development of modern evolutionary theory
should be viewed as a synthesis — that question is ignored here.
(^2) See Haldane [1937; 1957]. Crow [1992] has particularly emphasized the importance of these
contributions.
General editors: Dov M. Gabbay,
c
Handbook of the Philosophy of Science. Philosophy of Biology
Volume editors:
Paul Thagard and John Woods
Mohan Matthen and Christopher Stephens
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