“Then again, when I looked at our Senate-house (I mean the old building of Hostilius, not this new one; when it was enlarged, it diminished in my estimation), I used to think of Scipio, Cato, Laelius and in particular of my own grandfather.

“Such is the power of places to evoke associations; so it is with good reason that they are used as a basis for memory training."}]

No one can doubt but causation has the same influence as the other two relations; of resemblance and contiguity.  Superstitious people are fond of the relicks of saints and holy men, for the same reason that they seek after types and images, in order to enliven their devotion, and give them a more intimate and strong conception of those exemplary lives, which they desire to imitate.  Now it is evident, one of the best relicks a devotee coued procure, would be the handywork of a saint; and if his cloaths and furniture are ever to be considered in this light, it is because they were once at his disposal, and were moved and affected by him; in which respect they are to be considered as imperfect effects, and as connected with him by a shorter chain of consequences than any of those, from which we learn the reality of his existence.  This phaenomenon clearly proves, that a present impression with a relation of causation may, inliven any idea, and consequently produce belief or assent, according to the precedent definition of it.

But why need we seek for other arguments to prove, that a present impression with a relation or transition of the fancy may inliven any idea, when this very instance of our reasonings from cause and effect will alone suffice to that purpose?  It is certain we must have an idea of every matter of fact, which we believe.  It is certain, that this idea arises only from a relation to a present impression.  It is certain, that the belief super-adds nothing to the idea, but only changes our manner of conceiving it, and renders it more strong and lively.  The present conclusion concerning the influence of relation is the immediate consequence of all these steps; and every step appears to me sure end infallible.  There enters nothing into this operation of the mind but a present impression, a lively idea, and a relation or association in the fancy betwixt the impression and idea; so that there can be no suspicion of mistake.

In order to put this whole affair in a fuller light, let us consider it as a question in natural philosophy, which we must determine by experience and observation.  I suppose there is an object presented, from which I draw a certain conclusion, and form to myself ideas, which I am said to believe or assent to.  Here it is evident, that however that object, which is present to my senses, and that other, whose existence I infer by reasoning, may be thought to influence each other by their particular powers or qualities; yet as the phenomenon of belief, which we at present examine, is merely internal, these powers and qualities, being entirely unknown, can have no hand in producing it.  It is the present impression, which is to be considered as the true and real cause of the idea, and of the belief which attends it.  We must therefore endeavour to discover by experiments the particular qualities, by which it is enabled to produce so extraordinary an effect.