19. Little use of these maxims in proofs where we have clear and distinct ideas.
So that, if rightly considered, I
think we may say, That where our ideas are determined in our minds, and have annexed to them by us known and
steady names under those settled determinations, there is little need, or no use at all of these maxims, to prove the
agreement or disagreement of any of them. He that cannot discern the truth or falsehood of such propositions,
without the help of these and the like maxims, will not be helped by these maxims to do it: since he cannot be
supposed to know the truth of these maxims themselves without proof, if he cannot know the truth of others
without proof, which are as self-evident as these. Upon this ground it is that intuitive knowledge neither requires
nor admits any proof, one part of it more than another. He that will suppose it does, takes away the foundation of
all knowledge and certainty; and he that needs any proof to make him certain, and give his assent to this
proposition, that two are equal to two, will also have need of a proof to make him admit, that what is, is. He that
needs a probation to convince him that two are not three, that white is not black, that a triangle is not a circle, etc.,
or any other two [determined] distinct ideas are not one and the same, will need also a demonstration to convince
him that It is impossible for the same thing to be and not to be.
