particular recollections, he admits five agents or occasioning causes:
first, connection in time, whether simultaneous, preceding, or
successive; second, vicinity or connection in space; third,
interdependence or necessary connection, as cause and effect; fourth,
likeness; and fifth, contrast. As an additional solution of the
occasional seeming chasms in the continuity of reproduction he proves,
that movements or ideas possessing one or the other of these five
characters had passed through the mind as intermediate links,
sufficiently clear to recall other parts of the same total impressions
with which they had co-existed, though not vivid enough to excite that
degree of attention which is requisite for distinct recollection, or
as we may aptly express it, after consciousness. In association then
consists the whole mechanism of the reproduction of impressions, in
the Aristotelian Psychology. It is the universal law of the passive
fancy and mechanical memory; that which supplies to all other
faculties their objects, to all thought the elements of its materials.

In consulting the excellent commentary of St. Thomas Aquinas on the
Parva Naturalia of Aristotle, I was struck at once with its close
resemblance to Hume's Essay on Association. The main thoughts were the
same in both, the order of the thoughts was the same, and even the
illustrations differed only by Hume's occasional substitution of more
modern examples. I mentioned the circumstance to several of my
literary acquaintances, who admitted the closeness of the resemblance,
and that it seemed too great to be explained by mere coincidence; but
they thought it improbable that Hume should have held the pages of the
Angelic Doctor worth turning over. But some time after Mr. Payne
showed Sir James Mackintosh some odd volumes of St. Thomas Aquinas,
partly perhaps from having heard that he had in his Lectures passed a
high encomium on this canonized philosopher; but chiefly from the