He [Dawkins] seems to have little appreciation for the cognitive structure of science. Philosophers of science, who are the arbiters of such issues, say science consists largely of facts, laws and theories. The facts are the facts, the laws summarize the regularities in the facts, and the theories explain the laws. Evolution can fall into only of of these categories, and it's a theory.
And he responds:
Whoa. Scientists everywhere are doing a spit-take at those words. Philosophers, sweet as they may be, are most definitely not the "arbiters" of the cognitive structure of science. They are more like interested spectators, running alongside the locomotive of science, playing catch-up in order to figure out what it is doing, and occasionally shouting words of advice to the engineer, who might sometimes nod in interested agreement but is more likely to shrug and ignore the wacky academics with all the longwinded discourses. Personally, I think the philosophy of science is interesting stuff, and can surprise me with insights, but science is a much more pragmatic operation that doesn't do a lot of self-reflection.
This is surely right, despite the clunky metaphor. Part of the reason is that any 'philosophy of X' will by its nature have something of the Owl of Minerva to it (to use Hegel's excellent phrase): you can't have a philosophy of X without X to study. Philosophy in this mode always comes too late to tell you how things ought to be; it has to discover how things ought to be at the beginning if it is even to start in the right place. In the case of science in particular I think this can be very tricky for several reasons:
(1) The course of science keeps surprising everyone, including scientists. Part of scientific progress is the expansion of the sorts of things scientists study by the discovery of new tools and the like.
(2) Despite being largely ignored for most of the time since, Whewell was probably right a hundred-something years ago when he suggested that you really had to have a philosophy of sciences rather than a philosophy of science. Science is extraordinarily diverse, and therefore you are always running one of two dangers: either you manage to cover everything, and your claims about science end up being rather banal, because you have lost the richness of the detail, or you manage to come up with robust claims that only cover the particular area of science you happen to be looking at for the moment.
(3) Philosophy of science is, and has always been, a highly speculative venture. The best philosophy of science -- work of the quality of Whewell and Duhem and a handful of others -- has always been heavily grounded in actual facts about scientific inquiry. But it's important to understand (and while there are no doubt exceptions, I find that actual philosophers of science I've talked to do usually understand) that philosophy of science is heavy on hypothesis. These hypotheses get tested, sometimes sporadically and sometimes systematically, against the history of science and new directions science takes, but it's hard work, takes a long time to do properly, and has resulted in plenty of dead ends. To some extent this is the way any philosophy in 'problem' mode works -- that is, any philosophy of X, whatever X we may be considering. But it is often very noticeable in philosophy of science.
(4) Which is not to say that philosophers of science have not influenced the course of science; if you grew up with Kant and Mach like Einstein that would have an effect on the sort of questions you might ask, for instance. But this is the fourth reason it can be difficult to do philosophy of science. Much of the language in which people talk about the way science works is the philosophical terminology (often modified, sometimes deliberately, sometimes by accident) of decades ago. And if you are a philosopher of science you are often having to cut through the residue of your predecessors, seeking to shake off the bias of the way we used to think of things, trying to navigate the constantly shifting meaning of the terms we use to talk about science (especially if scientists use the term to talk about science, since from pretty much the beginning they have been taking words that they think have a nice sound -- i.e., that sound about right -- and using them in their own sense).
The list could no doubt be extended and improved; beyond a little bit of dabbling, it's not really my field, so I can only lay down rough outlines. But Wade's facts-laws-theories example shows many of the problems with talking about such things: which philosophers of science does he have in mind? What rigorous argument, if any, is supposed to lie behind the trichotomy? Why (as Myers goes on to note) are we taking these to be the most useful definitions, and why are we talking about evolutionary science as if it were a single unitary thing that could fit into only one of these categories? We are left in the dark. Conceivably he has some specific account in mind that would clear it all up, but it's unlikely, and, if it is the case, he forgot to give his readers a key to the lock.
I'd be interested, though, in what a philosopher of science would make of the dispute between the two.