mechanism
which, when certain keys are struck, gives rise to an accompaniment of
which the musician is only indirectly the cause. According to Descartes,
however--and this is what is generally fixed upon as the essence of his
doctrine of innate ideas--the mind possesses such an internal mechanism,
by which certain classes of thoughts are generated, on the occasion of
certain experiences. Such thoughts are innate, just as sensations are
innate; they are not copies of sensations, any more than sensations are
copies of motions; they are invariably generated in the mind, when
certain experiences arise in it, just as sensations are invariably
generated when certain bodily motions take place; they are universal,
inasmuch as they arise under the same conditions in all men; they are
necessary, because their genesis under these conditions is invariable.
These innate thoughts are what Descartes terms "verites" or truths: that
is beliefs--and his notions respecting them are plainly set forth in a
passage of the _Principes_.

"Thus far I have discussed that which we know as things: it remains
that I should speak of that which we know as truths. For example,
when we think that it is impossible to make anything out of
nothing, we do not imagine that this proposition is a thing which
exists, or a property of something, but we take it for a certain
eternal truth, which has its seat in the mind (_pensee_), and is
called a common notion or an axiom. Similarly, when we affirm that
it is impossible that one and the same thing should exist and not
exist at the same time; that that which has been created should not
have been created; that he who thinks must exist while he thinks;
and a number of other like propositions; these are only truths, and
not things which exist outside our thoughts. And there is such a
number of these that it would be wearisome to enumerate them: nor
is it necessary to do so, because we cannot fail to know them when
the occasion of thinking about them presents itself, and we are not
blinded by any prejudices."

It would appear that Locke was not more familiar with Descartes'
writings than Hume seems to have been; for, viewed in relation to the
passages just cited, the arguments adduced in his famous polemic against
innate ideas are totally irrelevant.

It has been shown that Hume practically, if not in so many words,
admits the justice