ortion with his wants.... In man alone this
unnatural conjunction of infirmity and of necessity may be observed in
the greatest perfection. Not only the food which is required for his
sustenance flies his search and approach, or at least requires his
labour to be produced, but he must be possessed of clothes and lodging
to defend him against the injuries of the weather: though to consider
him only in himself, he is provided neither with arms, nor force, nor
other natural abilities which are in any degree answerable to so many
'necessities.' 'Tis by society alone he is able to supply his defects
and raise himself up to an equality with his fellow-creatures, and even
acquires a superiority over them."[3] In these terms Hume draws the
distinction between man and the animals, and if, for the term Society,
we substitute the word Education, then we shall more truly describe the
means by which man overcomes his natural infirmities and meets his
necessities.

But we have to ask, Wherein does man differ from the animals? what power
or faculty does he possess over and above those possessed by himself and
the animals in common? and how does it happen that as his wants and
needs increase and multiply the means to satisfy them also tend to
increase? Now, the animal is guided wholly or mainly by instinct. In the
case of many animals the whole conduct of their life from birth to death
is governed by this means. In the case, indeed, of some of the higher
animals, there is a limited power of modifying this government by
instinct through the experience acquired during the lifetime of the
individual. But man alone possesses the power or faculty of reason. And
it is through the possession of this power that he alone of all
creatures can be educated; it is the possession of this power which
places him above the rest of creation, and it is in the possession of
this power that the possibility of his greatness, and also of his
baseness, lies. Now, an instinct may be defined as an inborn and
inherited system of means for the attainment of a definite end of such a
nature that once the appropriate external stimulus is applied the system
tends to work itself out in an automatic manner until the end is
attained, and independently of any control exercised by the individual.
The working out of such an action may be accompanied by consciousness,
but the power of memory would only be valuable in so far as the instinct
was imperfect, and in so far as th