Plato: The Republic

5. BOOK V (continued)

Yes.

And will you be so very good as to answer one more question? Would you say that knowledge is a faculty, or in what class would you place it?

Certainly knowledge is a faculty, and the mightiest of all faculties.

And is opinion also a faculty?

Certainly, he said; for opinion is that with which we are able to form an opinion.

And yet you were acknowledging a little while ago that knowledge is not the same as opinion?

Why, yes, he said: how can any reasonable being ever identify that which is infallible with that which errs?

An excellent answer, proving, I said, that we are quite conscious of a distinction between them.

Yes.

Then knowledge and opinion having distinct powers have also distinct spheres or subject-matters?

That is certain.

Being is the sphere or subject-matter of knowledge, and knowledge is to know the nature of being?

Yes.

And opinion is to have an opinion?

Yes.

And do we know what we opine? or is the subject-matter of opinion the same as the subject-matter of knowledge?

Nay, he replied, that has been already disproven; if difference in faculty implies difference in the sphere or subject matter, and if, as we were saying, opinion and knowledge are distinct faculties, then the sphere of knowledge and of opinion cannot be the same.

Then if being is the subject-matter of knowledge, something else must be the subject-matter of opinion?

Yes, something else.