(Univerzita Hradec Králové)
Primus Inter Pares: Philosophy of Language as First Philosophy
ABSTRAKT: It is an open question whether and in what sense non-linguistic animals are capable of cognitive acts that have logical content, and of how explicitly codified deduction systems like those of classical logic might relate to whatever sort of cognition non-human animals are capable of. In this essay, I draw on two-factor approaches to human cognition, as well as a joint model-theoretic and proof-theoretic semantics for natural language, to show that a practical capacity for accepting and rejecting cognitive acts accounts for cognition as having a deductive logical structure but not content. On this basis, I hypothesize that the ability to engage in such self-directed cognitive acts is an evolutionary bridge linking simpler non-human and linguistic human cognition. Relating the proposal to bilateral proof systems, I show that a unilateral account of deductive inference specified in terms of assertion alone, where logical operations are accounted for in terms of content rather than structure, would be more parsimonious in communicating over and propagating the rules of such systems. This provides a plausible explanation for why logical instruction would occur in a unilateral assertion-based rather than a bilateral framework today even if, in the etiology of these capacities, bilateral and rejection-based structure-inducing modes of logical thinking antedate unilateral assertion-based content-inducing modes.