prevail over that reason, which, however powerfully exerted on any
particular occasion, will probably comprehend but a partial view of the
subject; and our conduct in life, as well as in the arts, is or ought to
be generally governed by this habitual reason: it is our happiness that
we are enabled to draw on such funds. If we were obliged to enter into
a theoretical deliberation on every occasion before we act, life would
be at a stand, and Art would be impracticable.

'It appears to me therefore' (continues Sir Joshua) 'that our first
thoughts, that is, the effect which any thing produces on our minds on
its first appearance, is never to be forgotten; and it demands for that
reason, because it is the first, to be laid up with care. If this be
not done, the artist may happen to impose on himself by partial
reasoning; by a cold consideration of those animated thoughts which
proceed, not perhaps from caprice or rashness (as he may afterwards
conceit), but from the fulness of his mind, enriched with the copious
stores of all the various inventions which he had ever seen, or had ever
passed in his mind. These ideas are infused into his design, without
any conscious effort; but if he be not on his guard, he may reconsider
and correct them, till the whole matter is reduced to a commonplace
invention.

'This is sometimes the effect of what I mean to caution you against;
that is to say, an unfounded distrust of the imagination and feeling, in
favour of narrow, partial, confined, argumentative theories, and of
principles that seem to apply to the design in hand, without considering
those general impressions on the fancy in which real principles of
_sound reason_, and of much more weight and importance, are involved,
and, as it were, lie hid under the appearance of a sort of vulgar
sentiment. Reason, without doubt, must ultimately determine everything;