The ontology of reasons
An epistemic reason is a reason upon which a belief is based. In his article The Ontology of Epistemic Reasons, John Turri distinguishes between different theories about the ontology of epistemic reasons, that is, what reasons are.
Theories about what reasons are
Psychologism: All reasons are psychological items.
Anti-psychologism: No reason is a psychological item.
Dualism: Some but not all reasons are psychological items.
Turri does not attack dualism, which he says has so few advocates. He attacks two versions of anti-psychologism and defends a version of psychologism.
Two versions of anti-psychologism
Abstractionism: reasons are the propositional contents of a subject’s mental states.
Factualism: reasons are non-mental facts or states of affairs.
Here I present only one of Turri’s arguments against abstractionism and none against factualism.
Circularity argument against abstractionism
“Suppose I undergo a perceptual experience with the content <here’s a rectangular surface>, whereupon I come to believe <here’s a rectangular surface>. This seems like a perfectly good way to come to know that there’s a rectangular surface before me. According to abstractionism, in such a case my reason for believing the proposition <here’s a rectangular surface> is the proposition <here’s a rectangular surface>. But this means that in heeding the call of perceptual experience, I am moving in a circle.”
Turri asserts that we do not move in a circle in making this transition from the perceptual experience to the belief, so abstractionism has a false entailment, so abstractionism is false.
Turri, J. 2010. Refutation by elimination. Analysis 70: 35-39.