When we are accustomed to see two impressions conjoined together, the appearance or idea of the one immediately carries us to the idea of the other.
Being fully satisfyed on this head, I make a third set of experiments, in order to know, whether any thing be requisite, beside the customary transition, towards the production of this phaenomenon of belief.

I therefore change the first impression into an idea; and observe, that though the customary transition to the correlative idea still remains, yet there is in reality no belief nor perswasion.

A present impression, then, is absolutely requisite to this whole operation; and when after this I compare an impression with an idea, and find that their only difference consists in their different degrees of force and vivacity, I conclude upon the whole, that belief is a more vivid and intense conception of an idea, proceeding from its relation to a present impression.
Thus all probable reasoning is nothing but a species of sensation.

It is not solely in poetry and music, we must follow our taste and sentiment, but likewise in philosophy.

When I am convinced of any principle, it is only an idea, which strikes more strongly upon me.