A M N cannot excite b c by association, because it has never been associated with B C, is not, like a, the production of the former impression A, but an entirely new impression made from without, totally unconnected with the first. I understand then from the nature of association how a will excite b c, but not how A excites a. I understand how my thinking of Lincoln's-inn Hall, the impression of yesterday, should also lead me on the principle of association, to think of other things connected with that impression; but I cannot see how, according to this principle, there is any more connection between my seeing Lincoln's-inn Hall today, and recollecting my having seen it yesterday, than there is between the palace of St. Cloud, and John-O'Groat's house. Certainly the new impression is not the old one, nor the idea of the old one. What is it then that when this second impression is made on the mind determines it to connect itself with the first more than with any other indifferent impression, and which carries it forward in that particular direction which is necessary to its finding out its fellow; or setting aside this geographical reasoning, what is there in the action of the one on the mind that necessarily revives that of the other? Clearly, nothing of this has aught to do with association.
A question however occurs here which perplexes the subject a good deal, and which I shall state and answer as concisely as I can. I have hitherto endeavoured to shew that a particular present impression cannot excite the recollection of a past impression by association; that is, that ideas which have never been associated, cannot be said to excite one another by association. But still it may be asked whether a present impression may not excite the ideas associated with any similar impression, without first exciting a distinct recollection of the similar impression with
