Published online by Cambridge University Press: 28 February 2022
That there was some chance element to evolutionary change was clear even to Darwin (cf. Hodge 1987; also Hodge & Kohn 1986), but chance has assumed a more central role in evolutionary theory since the early decades of this century. It was certainly clear to theoreticians such as Dobzhansky, Wright and Fisher that an adequate evolutionary theory would have to take a stochastic form, though they disagreed as to the significance of chance in evolution (Gigerenzer et al., 1989, ch. 4; Turner 1987). As Beatty explains, the central difference is that in more modern treatments, not only is the origin of variations a matter of chance, their evolutionary fates are also matters of chance (Beatty 1984; cf. Beatty 1987). Probabilistic theories of evolutionary change, as we shall be concerned with them, emphasize this dependency of evolutionary fates on chance, and treat evolutionary change as irreducibly probabilistic.
The names of the authors are in reverse alphabetical order; the order has no other significance. RMB was supported by a residential fellowship at the National Humanities Center, funded by the National Endowment for the Humanities, and by a Study-Research leave from Virginia Polytechnic Institute and State University. RCR was supported by grants from the National Science Foundation and enjoyed the Taft Committee at the University of Cincinnati, and a residence at the Department of Philosophy and Religion at North Carolina State University. We gratefully acknowledge this support. We have benefitted from discussions with Janis Antonovics, John Beatty, Robert Brandon, Greg Cooper, Rebecca German, Donald Gustafson, Brent Mischler, W. E. Morris, and Kelly Smith.