from every other.  Were it not so, language would be unintelligible.  But it is so; and, therefore, to mistake one word for an other, is universally thought to betray great ignorance or great negligence, though such mistakes are by no means of uncommon occurrence.  But that the question about the identity of words is not a very easy one, may appear from the fact, that the learned often disagree about it in practice; as when one grammarian will have an and a to be two words, and an other will affirm them to be only different forms of one and the same word.

OBS. 6.—­Let us see, then, if amidst all this diversity we can find that principle of sameness, by which a dispute of this kind ought to be settled.  Now, although different words do generally differ in orthography, in pronunciation, and in meaning, so that an entire sameness implies one orthography, one pronunciation, and one meaning; yet some diversity is allowed in each of these respects, so that a sign differing from an other only in one, is not therefore a different word, or a sign agreeing with an other only in one, is not therefore the same word.  It follows thence, that the principle of verbal identity, the principle which distinguishes every word from every other, lies in neither extreme:  it lies in a narrower compass than in all three, and yet not singly in any one, but jointly in any two.  So that signs differing in any two of these characteristics of a word, are different words; and signs agreeing in any two, are the same word.  Consequently, if to any difference either of spelling or of sound we add a difference of signification everybody will immediately say, that we speak or write different words, and not the same:  thus dear, beloved, and deer, an animal, are two such words as no one would think to be the same; and, in like manner, use, advantage, and use, to employ, will readily be called different words.  Upon this principle, an and a are different words; yet, in conformity to old usage, and because the latter is in fact but an abridgement of the former, I have always treated them as one and the same article, though I have nowhere expressly called them the same word.  But, to establish the principle above named, which appears to me the only one on which any such question can be resolved, or the identity of words be fixed at all, we must assume that every word has one right pronunciation, and only one; one just orthography, and only one; and some proper signification, which, though perhaps not always the same, is always a part of its essence.  For when two words of different meaning are spelled or pronounced alike, not to maintain the second point of difference, against the double orthography or the double pronunciation of either, is to confound their identity at once, and to prove by the rule that two different words are one and the same, by first absurdly making them so.