The origin of classes of speech and of grammatical forms is to be found in antiquity, and as regards the latter, the disputes among the Alexandrian philosophers, the analogists, and the anomalists, resulted in logic being identified with grammar. Anything which did not seem logical was excluded from grammar as a deviation. The analogists, however, did not have it all their own way, and grammar in the modern sense of the word is a compromise between these extreme views, that is, it contains something of the thought of Chrysippus, who composed a treatise to show that the same thing can be expressed with different sounds, and of Apollonius Discolus, who attempted to explain what the rigorous analogists refused to admit into their schemes and classifications. It is only of late years that we have begun to emerge from the superstitious reverence for grammar, inherited from the Middle Age. Such writers as Pott, in his introduction to Humboldt, and Paul in his _Principien d. Sprachgeschichte_, have done good service in throwing doubt upon the absolute validity of the parts of speech. If the old superstitions still survive tenaciously, we must attribute this partly to empirical and poetical grammar, partly to the venerable antiquity of grammar itself, which has led the world to forget its illegitimate and turbid origin. The theory of the relativity of taste is likewise ancient, and it would be interesting to know whether the saying "there's no accounting for tastes" could be traced to a merely gustatory origin. In this sense, the saying would be quite correct, as it is _quite wrong_ when applied to aesthetic facts. The eighteenth century writers exhibit a piteous perplexity of thought on this subject. Home, for instance, after much debate, decides upon a common "standard of taste," which he deduces from the necessity of social life and from what he calls "a final cause." Of course it will not be an easy matter to fix this "standard of taste." As regards moral conduct, we do not seek our models among savages, so with regard to taste, we must have recourse to those few whose taste has not been corrupted nor spoilt by pleasure, who have received good taste from nature, and have perfected it by education and by the practice of life. If after this has been done, there should yet arise disputes, it will be necessary to refer to the principles of criticism, as laid down in his book by the said Home. We find similar contradictions and vicious circles in the _Discourse on Taste_ of David Hume. We search his writings in vain for the distinctive characteristics of the man of taste, whose judgments should be final. Although he asserts that the general principles of taste are universal in human nature, and admits that no notice should be accorded to perversions and ignorance, yet there exist diversities of taste that are irreconcilable, insuperable, and blameless.