acquired without meditation; the second comprehends all that the
experience of the senses dictates; the third, that which the
conversation of other men teaches us; to which may be added as the
fourth, the reading, not of all books, but especially of such as
have been written by persons capable of conveying proper
instruction, for it is a species of conversation we hold with their
authors. And it seems to me that all the wisdom we in ordinary
possess is acquired only in these four ways; for I do not class
divine revelation among them, because it does not conduct us by
degrees, but elevates us at once to an infallible faith.

There have been, indeed, in all ages great minds who endeavoured to
find a fifth road to wisdom, incomparably more sure and elevated
than the other four. The path they essayed was the search of first
causes and true principles, from which might be deduced the reasons
of all that can be known by man; and it is to them the appellation
of philosophers has been more especially accorded. I am not aware
that there is any one of them up to the present who has succeeded in
this enterprise. The first and chief whose writings we possess are
Plato and Aristotle, between whom there was no difference, except
that the former, following in the footsteps of his master, Socrates,
ingenuously confessed that he had never yet been able to find
anything certain, and that he was contented to write what seemed to
him probable, imagining, for this end, certain principles by which
he endeavoured to account for the other things. Aristotle, on the
other hand, characterised by less candour, although for twenty years
the disciple of Plato, and with no principles beyond those of his
master, completely reversed his mode of putting them, and proposed
as true and certain what it is probable he himself never esteemed as
such. But these two men had acquired much judgment and wisdom by the