remarked and rejected. And even in our wildest and most wandering
reveries, nay in our very dreams, we shall find, if we reflect, that the
imagination ran not altogether at adventures, but that there was still a
connexion upheld among the different ideas, which succeeded each other.
Were the loosest and freest conversation to be transcribed, there would
immediately be observed something which connected it in all its
transitions. Or where this is wanting, the person who broke the thread
of discourse might still inform you, that there had secretly revolved in
his mind a succession of thought, which had gradually led him from the
subject of conversation. Among different languages, even where we cannot
suspect the least connexion or communication, it is found, that the
words, expressive of ideas, the most compounded, do yet nearly
correspond to each other: a certain proof that the simple ideas,
comprehended in the compound ones, were bound together by some universal
principle, which had an equal influence on all mankind.

19. Though it be too obvious to escape observation, that different ideas
are connected together; I do not find that any philosopher has attempted
to enumerate or class all the principles of association; a subject,
however, that seems worthy of curiosity. To me, there appear to be only
three principles of connexion among ideas, namely, _Resemblance_,
_Contiguity_ in time or place, and _Cause or Effect_.

That these principles serve to connect ideas will not, I believe, be
much doubted. A picture naturally leads our thoughts to the original[2]:
the mention of one apartment in a building naturally introduces an
enquiry or discourse concerning the others[3]: and if we think of a
wound, we can scarcely forbear reflecting on the pain which follows
it[4]. But that this enumeration is complete, and that there are no
other principles of association except these, may be difficult to prove