alities
of human nature, ought at first to be rejected as presumptuous and
chimerical.

I do not think a philosopher, who would apply himself so earnestly to
the explaining the ultimate principles of the soul, would show himself a
great master in that very science of human nature, which he pretends to
explain, or very knowing in what is naturally satisfactory to the mind
of man. For nothing is more certain, than that despair has almost the
same effect upon us with enjoyment, and that we are no sooner acquainted
with the impossibility of satisfying any desire, than the desire itself
vanishes. When we see, that we have arrived at the utmost extent of
human reason, we sit down contented, though we be perfectly satisfied in
the main of our ignorance, and perceive that we can give no reason for
our most general and most refined principles, beside our experience
of their reality; which is the reason of the mere vulgar, and what it
required no study at first to have discovered for the most particular
and most extraordinary phaenomenon. And as this impossibility of making
any farther progress is enough to satisfy the reader, so the writer
may derive a more delicate satisfaction from the free confession of his
ignorance, and from his prudence in avoiding that error, into which so
many have fallen, of imposing their conjectures and hypotheses on the
world for the most certain principles. When this mutual contentment and
satisfaction can be obtained betwixt the master and scholar, I know not
what more we can require of our philosophy.

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. B