This idea was clearly articulated by Davidson (1989, 11): Just as in measuring weight we need a collection of entities which have a structure{ XE "structure" } in which we can reflect the relations between weighty objects, so in attributing states of belief{ XE "belief" } (and other propositional attitude{ XE "attitude: propositional" }s) we need a collection of entities related in ways that will allow us to keep track of the relevant properties of the various psychological states.
For the entities we mention to help specify a state of mind{ XE "mind" } do not have to play any psychological or epistemological role at all, just as numbers play no physical role.
Now let us be clear that we are not concerned here with synonymy in the sense of complete identity in psychological associations or poetic quality; indeed no two expressions are synonymous in such a sense.
The answer might be psychological, for example, that you will see them if you have had enough to eat.
Are these inquiries psychological?
No truth is found, except the psychological fact that I am satisfied with the result.
One might think that it is entirely a matter of psychology whether something is good or beautiful, that in comparing musical arrangements, for example, one is making a psychological experiment to determine which produces the more pleasing effect.
It is not a psychological one. Aesthetic discussion is something that goes on inside the range of likes and dislikes.
A statement about a visual or auditory impression, as against what causes it, need not be psychological.
If one gave psychological reasons for choosing a simile, those would not be reasons in aesthetics.