What is the difference between a posteriori and a priori in philosophy...?

Answer 1

a posteriori is knowledge justified by experience, based in empirical facts, sense data, &c.

"The cat is on the mat" is a fact iff there exists the cat in question that is on the mat. We have to appeal to the world to find out.

apriority has no admixture of experience; it is knowledge with evidence from deductive reason alone.

All analytic statements such as "all pediatricians are doctors" are a priori, given that it is true by definition alone. We don't have to check states of affairs to find out if a particular pediatrician is a doctor.

Answer 2

think of the words:
"priori" - prior (before)
"posteriori" - posterior (later)

If something happened "a priori" it happened before the fact.
If something happened "a posteriori" is happened after the fact.

I don't know what they mean specifically in psych, but knowing the meaning of the words will help you figure it out.

Answer 3

another way of looking at the terms...
a priori ...from the start.....
these are the assumptions that you start with....
and then working your way down to the particular events/aspects/conclusions

a posteriori...from the end....
take an event and work backwards to come up with the necessary starting factors/aspects/definitions