In this paper, we first extract from Susan Carey’s seminal account of the origin of concepts a notion of rationality, which is applicable to human infants and non-human animals; significantly different from the notions of rationality prevalent in behavioral ecology and yet, like these notions, amenable to empirical testing; conceptually more fundamental than the latter notions. Relatedly, this notion underlies a proto-conceptuality ascribable, by a key component of Carey’s account, to human infants and non-human animals. Based on a Kantian-inspired analysis (...) of fully-fledged conceptuality and the type of rationality underlying it, we then show the profound difference between the type of rationality extracted from Carey’s account and the rationality of human adults; related fundamental differences between the types of conceptual representation that these types of rationality respectively ground. By showing this, we highlight fundamental aspects of conceptual representations that are missing from Carey’s account of the origin of concepts. Based on this, we finally argue that, as ingenious and explanatorily valuable as Carey’s account of the origin of concepts is, it is only a partial account of this origin. (shrink)