Evolutionary naturalism provides an account of our capacities that undermines their reliability, and in doing so undermines itself...I agree with Alvin Plantinga that...the application of evolutionary theory to the understanding of our own cognitive capacities should undermine, though it need not completely destroy, our confidence in them. Mechanisms of belief formation that have selective advantage in the everyday struggle for existence do not warrant our confidence in the construction of theoretical accounts of the world as a whole. I think the evolutionary hypothesis would imply that though our cognitive capacities could be reliable, we do not have the kind of reason to rely on them that we ordinarily take ourselves to have using in them directly--as we do in science. Thomas Nagel, Mind and Cosmos, 27-28 (emphasis in original)
A non-trivial (albeit not the most fundamental) feature of Nagel's book (recall my here, here, here; see Feser's response to me and also Mohan's posts: here, here, here and here) is his reliance on Plantinga's so-called evolutionary argument against naturalism (hereafter EAAN; see also pp. 74-78). Let's leave aside the fact that Nagel pretends in his book that this (evolving) EAAN argument has not been subject to significant criticism. (It must be convenient to think that one is obliged to engage only with one's referee [Sober, although even his criticism of EAAN is ignored], one's colleague [Street], one's cheerleader [Plantinga], and one's deus ex machina [Hawthorne & Nolan].) Here I explore a response to this style of argument that is overlooked by Nagel and, I think, not explored in the literature (but would love to learn otherwise--it's not my field). So, let's grant -- for the sake of argument -- the claim that "Mechanisms of belief formation that have selective advantage in the everyday struggle for existence do not warrant our confidence in the construction of theoretical accounts of the world as a whole." What follows from this?
My quick and dirty answer is: nothing. For the crucial parts of science really do not rely on such mechanisms of belief formation. Much of scientific reason is or can be performed by machines; as I have argued before, ordinary cognition, perception, and locution does not really matter epistemically in the sciences.
Second, Nagel has a tendency to treat "the cognitive capacities" involved in theoretical accounts as importantly similar to each other; he tends to lump "mathematical or scientific reasoning" together (28 just after the quoted passage above, see also 72-5, 104-105). He also includes "ethics" in this lump. He thinks that somehow there are "norms of thought which, if we follow them, will tend to lead us toward the correct answers" to "factual and practical" questions. (72) Now, (i) if this claim is true, it is utterly unsubstantive--none of the non-trivial results in physics or mathematics are the consequence of following the norms of thought. (I realize that there is a conception of logic that treats it as providing us with the norms of thought, but even if one were to grant this conception, it does not follow one obtains thereby mathematical or scientific results worth having.) (ii) If Nagel's claim is true in ethics, this is so because a certain branch of ethical constructivism is tied to the laws of (human) rationality. But in the book Nagel rejects constructivism in ethics. (It's not clear if it is a strategic or substantive rejection.)
Now, Brian Leiter and Michael Weisberg have criticized Nagel for failing to engage with "contemporary cognitive science" in order to account for "our capacity to have thoughts about the world around us." Given the way Nagel sets up the problem, their charge seems to me correct. But on my reading of the situation, Nagel need not have done so if (iii) he could have shown how the scientific practices that generate the theoretical accounts of the world (as a whole, or in part) rely on cognitive practices that are the "mechanisms of belief formation that have selective advantage in the everyday struggle for existence." Nagel happily bypasses the half-century intensive interest in the philosophy of scientific practice (and the somewhat more recent interest in the philosophy of mathematical practice of the sort practiced by Catarina and Helen).
Okay, let's assume -- for the sake of argument -- that it matters that humans are engaged in scientific practices that generate the building blocks of theoretical accounts. In most of these the ordinary or average products of Darwinian evolution as such are not allowed near the lab. In fact, the ordinary or average products of primary, secondary, and university education are also not allowed inside the lab. Insanely high "achievement" over, say, twenty years of human capital formation is required before one becomes a little cog in the collaborative, scientific enterprise. (It's likely, in fact, that such achievement may just be a consequence of being a relatively rare freak of nature--a "monster" in eighteenth century vocabulary.) Parts of this achievement undoubtedly takes advantage of our selected for cognitive capacities and, perhaps, enhances these in subtle ways. A large art of this achievement is the actual unlearning -- or generating the capacity for temporary disabling -- lots of our avarage Darwinian programming. Moreover, much of the unlearning takes place after one's formal education is complete and inside the lab, where one's cognitive capacities are transformed into engagement with particular model organisms and particular specialized techniques. One does not need to accept all of Foucault, to see that the disciplining of scientific agents is as much an enhancement of human nature as a battle with pre-existing nature. So, "in science" our "cognitive capacities" are not used "directly." (Moreover, in so far as any human perception takes place in the epistemic processes of science much effort and skill is directed at making it entirely trivial.)
Nothing that I have just claimed undermines any evolutionary argument. In fact, the need for extensive training of scientific agents can be seen to be explained by evolutionary considerations; the environments on which past selection of our capacities have operated are dramatically different from those encountered in scientific labs and other ecologies where the building blocks for future theoretical accounts of the whole are explored/investigated. This is why, first, the overwhelming majority of agents are excluded from scientific processes and, second, those that are included need to be reprogrammed over decades of education.
In fact, here I do not want to claim that we should ever expect human-free science because human education is relatively cheap and safe compared to a lot of machine-building. But collectively philosophers of scientific practice have been learning that the protocols and the material, measuring, computing, mathematical, and statistical (etc.) technologies deployed in the sciences are all designed and constantly refined to allow us to safely ignore our ordinary cognitive capacities. (Quine-ean naturalized epistemology with its focus on retinas has long been replaced by varieties of social epistemology.) So-called "evolutionary naturalism" is not some exception to this: the mapping of the human genome, ordinary cell/molecular biology, and ordinary population genetics rely not just on mathematics, but especially on computers, mechanized/digitized measuring devices, and data-mining procedures to a very high degree. (This is not to deny that there is some heroic human field-work left inside this edifice.) Scientific speech (inside the lab, and in publications) is highly stylized, and whatever unifies the various forms of scientific cognition the most recognizable human elements in it are status seeking, the need to acquire scarce resources in competitive environment, loyalty, flattery, and the virtues of self-command and group collaboration.
As I have suggested before (here, here, and here; prompted by Mohan here, here, and here) reflection on scientific practices suggests that the mechanisms of scientific belief formation are very different from the mechanisms of belief formation discussed in recent epistemology (and even in the fascinating literature on testimony). So, what's the upshot of this? EAAN relies on an arm-chair view of science that has as its target an outdated, romantic view of science (with heroic scientific agents at the center of edifying narratives) that was probably never true. As Wikipedia reports: "the term "computer", in use from the mid 17th century, meant "one who computes": a person performing mathematical calculations, before electronic computers became commercially available. Teams of people were frequently used to undertake long and often tedious calculations; the work was divided so that this could be done in parallel." (There is a feminist issue lurking here: these human computers were generally women!) For science to be possible, humans always had to be made into imperfect machines and -- as reflection on the Huygens pendulum reveals -- the crucial theoretical variables of measurements were put inside machines.
Okay, I have gone on long enough. Just a final note: whatever Darwinism entails about ethics, those of us who are moral egalitarians, should try to resist the urge to think of ethical expertise as akin to scientific expertise (as Nagel is wont to do in Mind and Cosmos).