Fourthly, Of the three real Existences of which we have certain knowledge.
FOURTHLY, As to the fourth sort of our knowledge, viz.

of the REAL ACTUAL EXISTENCE OF THINGS, we have an intuitive knowledge of OUR OWN EXISTENCE, and a demonstrative knowledge of the existence of a GOD: of the existence of ANYTHING ELSE, we have no other but a sensitive knowledge; which extends not beyond the objects present to our senses.
22.

Our Ignorance great.
Our knowledge being so narrow, as I have shown, it will perhaps give us some light into the present state of our minds if we look a little into the dark side, and take a view of OUR IGNORANCE; which, being infinitely larger than our knowledge, may serve much to the quieting of disputes, and improvement of useful knowledge; if, discovering how far we have clear and distinct ideas, we confine our thoughts within the contemplation of those things that are within the reach of our understandings, and launch not out into that abyss of darkness, (where we have not eyes to see, nor faculties to perceive anything), out of a presumption that nothing is beyond our comprehension.

But to be satisfied of the folly of such a conceit, we need not go far.

He that knows anything, knows this, in the first place, that he need not seek long for instances of his ignorance.