uently is the quality, by which they operate. We have farther
proved, that the most considerable causes of these passions are
really nothing but the power of producing either agreeable or uneasy
sensations; and therefore that all their effects, and amongst the rest,
pride and humility, are derived solely from that origin. Such simple
and natural principles, founded on such solid proofs, cannot fail to be
received by philosophers, unless opposed by some objections, that have
escaped me.

It is usual with anatomists to join their observations and experiments
on human bodies to those on beasts, and from the agreement of these
experiments to derive an additional argument for any particular
hypothesis. It is indeed certain, that where the structure of parts in
brutes is the same as in men, and the operation of these parts also
the same, the causes of that operation cannot be different, and that
whatever we discover to be true of the one species, may be concluded
without hesitation to be certain of the other. Thus though the mixture
of humours and the composition of minute parts may justly be presumed
so be somewhat different in men from what it is in mere animals; and
therefore any experiment we make upon the one concerning the effects of
medicines will not always apply to the other; yet as the structure of
the veins and muscles, the fabric and situation of the heart, of the
lungs, the stomach, the liver and other parts, are the same or nearly
the same in all animals, the very same hypothesis, which in one species
explains muscular motion, the progress of the chyle, the circulation of
the blood, must be applicable to every one; and according as it
agrees or disagrees with the experiments we may make in any species of
creatures, we may draw a proof of its truth or falshood on the whole.
Let us, therefore, apply this method of enquiry, which is found so just
and useful in reasonings concerning the body, to our present anatomy of
the mind, and see what discoveries we can make by it.

In order to this we must first shew the correspondence of passions in
men and animals, and afterwards compare the causes, which produce these
passions.

It is plain, that almost in every species of creatures, but especially
of the nobler kind, there are many evident marks of pride and humility.
The very port and gait of a swan, or turkey, or peacock show the high
idea he has entertained of himself, and his contempt of all others. This
is the mor