is, that self-evidence has degrees: it is not a quality
which is simply present or absent, but a quality which may be more or
less present, in gradations ranging from absolute certainty down to an
almost imperceptible faintness. Truths of perception and some of the
principles of logic have the very highest degree of self-evidence;
truths of immediate memory have an almost equally high degree. The
inductive principle has less self-evidence than some of the other
principles of logic, such as 'what follows from a true premiss must be
true'. Memories have a diminishing self-evidence as they become remoter
and fainter; the truths of logic and mathematics have (broadly speaking)
less self-evidence as they become more complicated. Judgements of
intrinsic ethical or aesthetic value are apt to have some self-evidence,
but not much.

Degrees of self-evidence are important in the theory of knowledge,
since, if propositions may (as seems likely) have some degree of
self-evidence without being true, it will not be necessary to abandon
all connexion between self-evidence and truth, but merely to say that,
where there is a conflict, the more self-evident proposition is to be
retained and the less self-evident rejected.

It seems, however, highly probable that two different notions are
combined in 'self-evidence' as above explained; that one of them,
which corresponds to the highest degree of self-evidence, is really an
infallible guarantee of truth, while the other, which corresponds to
all the other degrees, does not give an infallible guarantee, but only a
greater or less presumption. This, however, is only a suggestion, which
we cannot as yet develop further. After we have dealt with the nature
of truth, we shall return to the subject of self-evidence, in connexion
with the distinction between knowledge and error.

CHAPTER XII. TRUTH AND FALSEHOOD

Our knowledge of truths, unlike our knowledge of things, has an
opposite, namely _error_. So far as things are concerned, we may know
them or not know them, but there is no positive state of mind which can
be described as erroneous knowledge of things, so long, at any rate,
as we confine ourselves to knowledge by acquaintance. Whatever we are
acquainted with must be something; we may draw wrong inferences from
our acquaintance, but the acquaintance itself cannot be deceptive. Thus
there is no dualism as regards acquaintance. But as regards knowledge of
truths, there is a dualism.