First we must define the terms 'noun' and 'verb', then the terms
'denial' and 'affirmation', then 'proposition' and 'sentence.'
Spoken words are the symbols of mental experience and written
words are the symbols of spoken words. Just as all men have not the
same writing, so all men have not the same speech sounds, but the
mental experiences, which these directly symbolize, are the same for
all, as also are those things of which our experiences are the images.
This matter has, however, been discussed in my treatise about the
soul, for it belongs to an investigation distinct from that which lies
As there are in the mind thoughts which do not involve truth or
falsity, and also those which must be either true or false, so it is
in speech. For truth and falsity imply combination and separation.
Nouns and verbs, provided nothing is added, are like thoughts
without combination or separation; 'man' and 'white', as isolated
terms, are not yet either true or false. In proof of this, consider
the word 'goat-stag.' It has significance, but there is no truth or
falsity about it, unless 'is' or 'is not' is added, either in the
present or in some other tense.
By a noun we mean a sound significant by convention, which has no
reference to time, and of which no part is significant apart from
the rest. In the noun 'Fairsteed,' the part 'steed' has no
significance in and by itself, as in the phrase 'fair steed.' Yet
there is a difference between simple and composite nouns; for in the
former the part is in no way significant, in the latter it contributes
to the meaning of the whole, although it has not an independent