to know (for that is manifestly impossible), nor even to learn
everything that is known, for that would soon prove a tedious and
heart-breaking task; we should rather study the means to be employed
for warding off those sudden and public convictions of Ignorance
which are the ruin of so many.

These methods of defence are very numerous and are for the most part
easy of acquirement. The most powerful of them by far (but the most
dangerous) is to fly into a passion and marvel how anyone can be
such a fool as to pay attention to wretched trifles. "Powerful,"
because it appeals to that strongest of all passions in men by which
they are predisposed to cringe before what they think to be a
superior station in society. "Dangerous," because if it fail in its
objects this method does not save you from pain, and secures you in
addition a bad quarrel, and perhaps a heavy beating. Still it has
many votaries, and is more often carried off than any other. Thus,
if in Bedfordshire, someone catches you erring on a matter of crops,
you profess that in London such things are thought mere rubbish and
despised; or again, in the society of professors at the
Universities, an ignorance of letters can easily be turned by an
allusion to that vapid life of the rich, where letters grow
insignificant; so at sea, if you slip on common terms, speak a
little of your luxurious occupations on land and you will usually be
safe.

There are other and better defences. One of these is to turn the
attack by showing great knowledge on a cognate point, or by
remembering that the knowledge your opponent boasts has been
somewhere contradicted by an authority. Thus, if some day a friend
should say, as continually happens in a London club: