Perception and Propositions

Perception and Propositions

In order to have a theory of the origins of knowledge one needs an account of the origins of the proposition, i.e., propositional thought. How do we come to grasp propositions? It is notable that empiricists don’t venture an answer; they stick to the origins of concepts (“ideas”). They vaguely suppose that concepts combine in some unspecified way to produce propositional thoughts that correspond in some way with reality. They don’t suppose that perceptions (“impressions”) possess propositional content—rightly so. So, they don’t hold that thought content is abstracted from perceptual content: they don’t suppose that the content of propositional knowledge is a “faint copy” of the propositional content of perceptions. What would that even mean? Perception just doesn’t have propositional content prior to the formation of propositional thought (or knowledge). So, they have no account of the origins of our knowledge of propositional structure—our propositional competence. This will involve logical relations and knowledge thereof. For all they have said, the rationalists are right about this—it is a priori and innate. Therefore, empiricism is not true even of our most basic knowledge (“That’s red”). Perception alone cannot explain propositions. Suppose they abandoned their non-propositional view of perception and claimed that perception does embed propositions. Then they would face the question of where these propositions come from—for they can’t come from non-propositional perception. They would again fall into the hands of the rationalists who would insist that such propositional structure must be a priori and innate. Thus, propositions refute empiricism.[1]

[1] The case is rather like knowledge of language: you can’t derive knowledge of grammar from knowledge of the lexicon, so even if the latter were empirically acquired it would not follow that the former is so acquired. For example, in the case of non-linguistic knowledge, knowledge of the operation of predication cannot be derived from perception of physical objects, even if knowledge of red can be so derived.