4. An end and use of pain.
Pain has the same efficacy and use to set us on work that pleasure has, we being as
ready to employ our faculties to avoid that, as to pursue this: only this is worth our consideration, that pain is
often produced by the same objects and ideas that produce pleasure in us. This their near conjunction, which
makes us often feel pain in the sensations where we expected pleasure, gives us new occasion of admiring the
wisdom and goodness of our Maker, who, designing the preservation of our being, has annexed pain to the
application of many things to our bodies, to warn us of the harm that they will do, and as advices to withdraw
from them. But he, not designing our preservation barely, but the preservation of every part and organ in its
perfection, hath in many cases annexed pain to those very ideas which delight us. Thus heat, that is very agreeable
to us in one degree, by a little greater increase of it proves no ordinary torment: and the most pleasant of all
sensible objects, light itself, if there be too much of it, if increased beyond a due proportion to our eyes, causes a
very painful sensation. Which is wisely and favourably so ordered by nature, that when any object does, by the
vehemency of its operation, disorder the instruments of sensation, whose structures cannot but be very nice and
delicate, we might, by the pain, be warned to withdraw, before the organ be quite put out of order, and so be
unfitted for its proper function for the future. The consideration of those objects that produce it may well persuade
us, that this is the end or use of pain. For, though great light be insufferable to our eyes, yet the highest degree of
darkness does not at all disease them: because that, causing no disorderly motion in it, leaves that curious organ
unharmed in its natural state. But yet excess of cold as well as heat pains us: because it is equally destructive to
that temper which is necessary to the preservation of life, and the exercise of the several functions of the body,
and which consists in a moderate degree of warmth; or, if you please, a motion of the insensible parts of our
bodies, confined within certain bounds.