6. Knowledge of our capacity a cure of scepticism and idleness.
When we know our own strength, we shall the
better know what to undertake with hopes of success; and when we have well surveyed the powers of our own
minds, and made some estimate what we may expect from them, we shall not be inclined either to sit still, and not
set our thoughts on work at all, in despair of knowing anything; nor on the other side, question everything, and
disclaim all knowledge, because some things are not to be understood. It is of great use to the sailor to know the
length of his line, though he cannot with it fathom all the depths of the ocean. It is well he knows that it is long
enough to reach the bottom, at such places as are necessary to direct his voyage, and caution him against running
upon shoals that may ruin him. Our business here is not to know all things, but those which concern our conduct.
If we can find out those measures, whereby a rational creature, put in that state in which man is in this world, may
and ought to govern his opinions, and actions depending thereon, we need not to be troubled that some other
things escape our knowledge.