ained or generalised. We have in countless
cases a certain connection established for which no further reason can
be assigned than the fact of its previous occurrence. On such a
ground, we believe that fire burns, that bread is wholesome, that
stones fall; and but for such beliefs could know nothing of the
outside world. 'Contingent' truth, therefore, or truth derived from
mere contact, pervades, if it does not constitute, the whole fabric of
our whole knowledge. To prove that all our knowledge is derived from
experience is, according to Mill, to prove that in some sense or other
association of ideas lies at the base of all intellectual processes.
When Locke introduced a chapter upon 'Association of Ideas' into the
fourth edition of his essay, he treated it as the exceptional case.
Some ideas had a connection traceable by reason; others were only
connected by 'chance and custom.' Association does not explain
reasoning, only the deviations from reasoning. But with Hume and
Hartley the relation is inverted. The principle, instead of being an
exceptional case, is simply the universal rule from which logical
connection may be deduced as a special case.

The facts upon which Mill relied, and the account of them which he
gave, require notice and embodiment in any sound psychology. In some
shape or other they form the starting-point of all later systems.
Mill's vigorous application of his principle, worked out with
imperfect appreciation and with many oversights, had therefrom, at
least, the merit of preparing the ground for a more scientific method.
In any case, however, his conclusions, so far as sound, must be placed
in a different framework of theory. It becomes necessary to dwell
chiefly upon the curious defects of his theory, if taken as he wished
it to be taken, for an ultimate scientific statement. The fact that
there is a synthesis and an analysis is expressed by 'association.'
But what more can we say? What are the 'laws' of association? Unless
some rule can be given, we shall get nothing that can be called a
theory. One idea is not suggested by the other through any logical
process. They are still 'conjoined' but not 'connected.' The
connection, therefore, must be given by something different from the
ideas themselves. Now the order of the original 'sensations' depends
upon the 'objects of nature,' and is therefore left to 'physical
philosophy.'[516] They occur, however, either in 'synchronous' or in
'successive' o