oncerning Human Understanding_, which,
perhaps, I ought to assume to be well known to all English readers, but
which so probably is unknown to this full-crammed and much examined
generation that I venture to cite it:

"If by this inquiry into the nature of the understanding I can
discover the powers thereof, how far they reach, to what things
they are in any degree proportionate, and where they fail us, I
suppose it may be of use to prevail with the busy mind of man to be
more cautious in meddling with things exceeding its comprehension:
to stop when it is at the utmost extent of its tether; and to sit
down in quiet ignorance of those things which, upon examination,
are proved to be beyond the reach of our capacities. We should not
then, perhaps, be so forward, out of an affectation of universal
knowledge, to raise questions and perplex ourselves and others with
disputes about things to which our understandings are not suited,
and of which we cannot frame in our minds any clear and distinct
perception, or whereof (as it has, perhaps, too often happened) we
have not any notion at all.... Men may find matter sufficient to
busy their heads and employ their hands with variety, delight, and
satisfaction, if they will not boldly quarrel with their own
constitution and throw away the blessings their hands are filled
with because they are not big enough to grasp everything. We shall
not have much reason to complain of the narrowness of our minds, if
we will but employ them about what may be of use to us: for of that
they are very capable: and it will be an unpardonable, as well as a
childish peevishness, if we under-value the advantages of our
knowledge, and neglect to improve it to the ends for which it was
given us, because there are some things that are set out of the
reach of it. It will be no excuse to an idle and untoward servant
who would not attend to his business by candlelight, to plead that
he had not broad sunshine. The candle that is set up in us shines
bright enough for all our purposes.... Our business here is not to
know all things, but those which concern our conduct."[16]

Hume develops the same fundamental conception in a somewhat different
way, and with a more definite indication of the practical benefits which
may be expected from a critical philosophy. The first a