These observations must suffice to show that all the scientific problems of Linguistic are the same as those of Aesthetic, and that the truths and errors of the one are the truths and errors of the other. If Linguistic and Aesthetic appear to be two different sciences, this arises from the fact that people think of the former as grammar, or as a mixture between philosophy and grammar, that is, an arbitrary mnemonic scheme. They do not think of it as a rational science and as a pure philosophy of speech. Grammar, or something grammatical, also causes the prejudice in people's minds, that the reality of language lies in isolated and combinable words, not in living discourse among expressive organisms, rationally indivisible. Those linguists, or glottologists with philosophical endowments, who have best fathomed questions of language, resemble (to employ a worn but efficacious figure) workmen piercing a tunnel: at a certain point they must hear the voices of their companions, the philosophers of Aesthetic, who have been piercing it from the other side. At a certain stage of scientific elaboration, Linguistic, in so far as it is philosophy, must be merged in Aesthetic; and indeed it is merged in it, without leaving a residue. HISTORICAL SUMMARY I AESTHETIC IDEAS IN GRAECO-ROMAN ANTIQUITY The question, as to whether Aesthetic should be looked upon as ancient or modern, has often been discussed. The answer will depend upon the view taken of the nature of Aesthetic. Benedetto Croce has proved that Aesthetic is _the science of expressive activity_. But this knowledge cannot be reached, until has been defined the nature of imagination, of representation, of expression, or whatever we may term that faculty which is theoretic, but not intellectual, which gives knowledge of the individual, but not of the universal. Now the deviations from this, the correct theory, may arise in two ways: by _defect_ or by _excess_. Negation of the special aesthetic activity, or of its autonomy, is an instance of the former. This amounts to a mutilation of the reality of the spirit. Of the latter, the substitution or superposition of another mysterious and non-existent activity is an example. These errors each take several forms. That which errs by defect may be: (_a_) pure hedonism, which looks upon art as merely sensual pleasure; (_b_) rigoristic hedonism, agreeing with (_a_), but adding that art is irreconcilable with the loftiest activities of man; (_c_) moralistic or pedagogic hedonism, which admits, with the two former, that art is mere sensuality, but believes that it may not only be harmless, but of some service to morals, if kept in proper subjection and obedience. The error by excess also assumes several forms, but these are indeterminable _a priori_. This view is fully dealt with under the name of _mystic_, in the Theory and in the Appendix.