This Agreement or Disagreement may be any of four sorts.
But to understand a little more distinctly wherein this agreement or disagreement consists, I think we may reduce it all to these four sorts: I.IDENTITY, or DIVERSITY.II.RELATION.III.

CO-EXISTENCE, or NECESSARY CONNEXION.IV.REAL EXISTENCE.
4.

First, Of Identity, or Diversity in ideas.
FIRST, As to the first sort of agreement or disagreement, viz.

IDENTITY or DIVERSITY.

It is the first act of the mind, when it has any sentiments or ideas at all, to perceive its ideas; and so far as it perceives them, to know each what it is, and thereby also to perceive their difference, and that one is not another.