From Philip Kitcher's letter in the New York Times:
To the Editor:
In his review of “The Greatest Show on Earth,” Nicholas Wade charges that Richard Dawkins is guilty of a philosophical error. According to Wade, philosophers of science divide scientific propositions into three types — facts, laws and theories — and, contrary to Dawkins’s assertions, evolution, which is plainly a systematic theory, cannot count as a fact. However, contemporary philosophy of science offers a vastly more intricate vocabulary for thinking about the sciences than that presupposed in Wade’s oversimplified taxonomy and in his confused remarks about “absolute truth.” Although philosophers may quarrel with aspects of Dawkins’s arguments on a range of issues, he has a far firmer and more subtle understanding of the philosophical issues than that manifested in Wade’s review.
The crucial point is that, as Dawkins appreciates, the distinction between theory and fact, in philosophical discussions as in everyday speech, can be drawn in two quite distinct ways.