world.

There is a criterion by which we may distinguish our voluntary acts or
thoughts from those that are excited by our sensations: "The former are
always employed about the _means_ to acquire pleasureable objects, or to
avoid painful ones: while the latter are employed about the _possession_ of
those that are already in our power."

If we turn our eyes upon the fabric of our fellow animals, we find they are
supported with bones, covered with skins, moved by muscles; that they
possess the same senses, acknowledge the same appetites, and are nourished
by the same aliment with ourselves; and we should hence conclude from the
strongest analogy, that their internal faculties were also in some measure
similar to our own.

Mr. Locke indeed published an opinion, that other animals possessed no
abstract or general ideas, and thought this circumstance was the barrier
between the brute and the human world. But these abstracted ideas have been
since demonstrated by Bishop Berkley, and allowed by Mr. Hume, to have no
existence in nature, not even in the mind of their inventor, and we are
hence necessitated to look for some other mark of distinction.

The ideas and actions of brutes, like those of children, are almost
perpetually produced by their present pleasures, or their present pains;
and, except in the few instances that have been mentioned in this Section,
they seldom busy themselves about the _means_ of procuring future bliss, or
of avoiding future misery.

Whilst the acquiring of languages, the making of tools, and the labouring
for money; which are all only the _means_ of procuring pleasure; and the
praying to the Deity, as another _means_ to procure happiness, are
characteristic of human nature.

* * * * *

SECT. XVII.

THE CATENATION OF MOTIONS.

I. 1. _Catenations of animal motion._ 2. _Are produced by irritations,
by sensations, by volitions._ 3. _They continue some time after they
have been excited. Cause of catenation._ 4. _We can then exert our
attention on other objects._ 5. _Many catenations of motions go on
together._ 6. _Some links of the catenations of motions may be left out
without disuniting the chain._ 7. _Interrupted circles of motion
continue confusedly till they come to the part of the circle, where
they were disturbed._ 8. _Weaker catenations are dissevered by
stronger._ 9. _Then new catenations take place._ 10. _Much effort