And here it is evident we must confine ourselves to resemblance and causation, and must drop contiguity, which has little or no influence in the present case.
To begin with resemblance; suppose we coued see clearly into the breast of another, and observe that succession of perceptions, which constitutes his mind or thinking principle, and suppose that he always preserves the memory of a considerable part of past perceptions; it is evident that nothing coued more contribute to the bestowing a relation on this succession amidst all its variations.

For what is the memory but a faculty, by which we raise up the images of past perceptions?
And as an image necessarily resembles its object, must not.

The frequent placing of these resembling perceptions in the chain of thought, convey the imagination more easily from one link to another, and make the whole seem like the continuance of one object?
In this particular, then, the memory not only discovers the identity, but also contributes to its production, by producing the relation of resemblance among the perceptions.

The case is the same whether we consider ourselves or others.
As to causation; we may observe, that the true idea of the human mind, is to consider it as a system of different perceptions or different existences, which are linked together by the relation of cause and effect, and mutually produce, destroy, influence, and modify each other.
Our impressions give rise to their correspondent ideas; said these ideas in their turn produce other impressions.

One thought chaces another, and draws after it a third, by which it is expelled in its turn.