Contributors were John Dupré, Peter J. Richerson and Robert Boyd, John Beatty, Philip Kitcher, Elliott Sober, John Maynard Smith, Richard C. Lewontin, John M. Emlen, John E. R. Staddon, Eric Alden Smith, Roger N. Shepard, Leda Cosmides and John Tooby, and Jack Hirshleifer.
I do not say that this is an angels on the head of the pin kind of argument, but that evolutionary theory governs a vast domain of data -- all life forms across aeons -- and that the theory results from an intricate web of inferences, and therefore can take any one of many mazy paths.
There's nothing categorical, straightforward, or black/white about evolutionary theory, which is why I find boddi's and Arash's simplistic arguments irritating. So I would echo the injunction to read more, not in order to find the right answer, but in order to appreciate the complexity of this theory.
Joanna