We may believe what is false as well as
what is true. We know that on very many subjects different people
hold different and incompatible opinions: hence some beliefs must be
erroneous. Since erroneous beliefs are often held just as strongly
as true beliefs, it becomes a difficult question how they are to be
distinguished from true beliefs. How are we to know, in a given case,
that our belief is not erroneous? This is a question of the very
greatest difficulty, to which no completely satisfactory answer is
possible. There is, however, a preliminary question which is rather less
difficult, and that is: What do we _mean_ by truth and falsehood? It is
this preliminary question which is to be considered in this chapter. In
this chapter we are not asking how we can know whether a belief is true
or false: we are asking what is meant by the question whether a belief
is true or false. It is to be hoped that a clear answer to this question
may help us to obtain an answer to the question what beliefs are
true, but for the present we ask only 'What is truth?' and 'What is
falsehood?' not 'What beliefs are true?' and 'What beliefs are false?'
It is very important to keep these different questions entirely
separate, since any confusion between them is sure to produce an answer
which is not really applicable to either.

There are three points to observe in the attempt to discover the nature
of truth, three requisites which any theory must fulfil.

(1) Our theory of truth must be such as to admit of its opposite,
falsehood. A good many philosophers have failed adequately to satisfy
this condition: they have constructed theories according to which all
our thinking ought to have been true, and have then had the greatest
difficulty in finding a place for falsehood. In this respect our theory
of belief must differ from our theory of acquaintance, since in the case
of acquaintance it was not necessary to take account of any opposite.

(2) It seems fairly evident that if there were no beliefs there could
be no falsehood, and no truth either, in the sense in which truth is
correlative to falsehood. If we imagine a world of mere matter, there
would be no room for falsehood in such a world, and although it would
contain what may be called 'facts', it would not contain any truths, in
the sense in which truths are things of the same kind as falsehoods.
In fact, truth and falsehood are properties of beliefs and statements:
hence a world of mer