As I mentioned in the first blogpost, one aspect of some cognitive kinds that I try to emphasize throughout the book is their externalism, or as I have put it, their “etiological-environmental individuation.” This cumbersome expression is a more accurate way of describing the taxonomic practices that I highlight. It is misleading to describe the factors with reference to which some cognitive kinds are individuated as “external” primarily because the term “external” is insufficiently descriptive and does not indicate the precise features of reality that serve to ground these cognitive categories. In many of the cases I discuss, what matters most is etiology: the causal history of the entities in question. Moreover, the causal history sometimes pertains to the developmental history of the individual (ontogeny) and at other times to the history of the species (phylogeny).
Externalism is commonly regarded as an established thesis in the philosophy of mind (though it is not without its detractors), but I try to distinguish the version of externalism defended in the book from other varieties of externalism in the philosophy of mind and cognitive science. As is widely known, there are two major philosophical proposals that emphasize the role of the “external world” in understanding the mind.
The first is the “active externalism” or “extended mind thesis,” which holds that mental states and processes are characterized by “reliable coupling” with features of the environment. However, the type of externalism that I advocate is not just about causal coupling but about the very identification or individuation of cognitive kinds. I try to show that many features of cognition are individuated with reference to their environment or etiology. This claim is more far-reaching than “active externalism” since it says that when it comes to something like a state of episodic memory (say), it is not even possible to identify it without invoking its causal history. This means that, at least for some cognitive kinds, it is not clear how to frame the thesis that “internal” states are coupled with “external” entities, since it is misguided to talk about cognitive states being internal in the first place.
The second is the standard externalist thesis that is encapsulated in the expression, meanings “just ain’t in the head.” This is explicitly an individuative thesis, but it is usually restricted to meanings, concepts, or semantic content. Concurring with this claim, I argue in the book that externalism holds for concepts (though I think they are individuated on the basis of both externalistic and internalistic factors), but I also put forward reasons for thinking that it applies to other cognitive kinds, such as innateness, domain specificity, episodic memory, and myside bias. Moreover, the arguments I make rely not on intuitive judgments concerning the ascription of conceptual contents, but taxonomic practices in cognitive science. For example, when it comes to concepts, I present evidence to show that much of the empirical work in developmental psychology individuates the concepts of concept learners (partly) according to their etiology in the natural and social worlds.
Etiological individuation is not the only type of relational individuation in cognitive science; in some cases, the synchronic environment of the thinker also plays a role in determining the identity of the cognitive kind that is manifested. For example, in the case of the myside heuristic (a psychological disposition closely related to confirmation bias), determining whether an instance of the heuristic is indeed a bias requires doing so against the background of a particular cognitive task or problem. Hence, if researchers want to distinguish a myside bias from a myside heuristic, they can only do so with reference to the synchronic context of the thinker.
The etiological-environmental individuation of cognitive kinds is not only directly supported by taxonomic practices in cognitive science, but it is also more far-reaching than many externalists tend to assume. Moreover, some of the implications of externalism do not appear to have been widely acknowledged. In particular, apart from occasional stray remarks by a few philosophers, it is not generally appreciated that the environmental-etiological individuation of cognitive categories may scuttle neat matchups with neural categories, which are individuated either intrinsically or with regard to different relational factors.
If neuroscience should not expect to find neural correlates for cognitive categories, how are we to proceed to build bridges between cognitive psychology and neuroscience? Specifically, what happens to cognitive neuroscience if investigators are not supposed to engage, for example, in reverse inference, which presumes that a particular cognitive capacity is being deployed on the grounds that its associated brain region is active?
If there are no neat matchups between cognitive phenomena and neural ones, such inferences would appear to be ruled out and this methodological strategy would need to be revised. Such matchups are by no means always out of reach. It’s just that many cognitive kinds cannot be expected to correlate with neural kinds for principled reasons that hold across the cognitive domain. This outcome is to be expected given the precedent of other closely related pairs of sciences. Despite the intricate and intimate relationships between, say, ecology and genetics, to take another pair of sciences, there is no expectation that their considered categories will enter into a one-to-one correspondence. To be sure, there is a sub-discipline of ecological genetics, but it does not revolve around the search for genetic correlates of ecological constructs.