But if this impossibility of explaining ultimate principles should be
esteemed a defect in the science of man, I will venture to affirm, that
it is a defect common to it with all the sciences, and all the arts, in
which we can employ ourselves, whether they be such as are cultivated in
the schools of the philosophers, or practised in the shops of the meanest
artizans. None of them can go beyond experience, or establish any
principles which are not founded on that authority. Moral philosophy has,
indeed, this peculiar disadvantage, which is not found in natural, that
in collecting its experiments, it cannot make them purposely, with
premeditation, and after such a manner as to satisfy itself concerning
every particular difficulty which may be. When I am at a loss to know the
effects of one body upon another in any situation, I need only put them
in that situation, and observe what results from it. But should I
endeavour to clear up after the same manner any doubt in moral
philosophy, by placing myself in the same case with that which I
consider, it is evident this reflection and premeditation would so disturb
the operation of my natural principles, as must render it impossible to
form any just conclusion from the phenomenon. We must therefore glean up
our experiments in this science from a cautious observation of human
life, and take them as they appear in the common course of the world, by
men's behaviour in company, in affairs, and in their pleasures. Where
experiments of this kind are judiciously collected and compared, we may
hope to establish on them a science which will not be inferior in
certainty, and will be much superior in utility to any other of human
comprehension.