With this, the notion of Form opens out immensely. Not only the technical instrument, not only the form-language, but also _the choice of art-genus itself_ is seen to be an expression-means. What the creation of a masterpiece means for an individual artist—the “Night Watch” for Rembrandt or the “Meistersinger” for Wagner—that the creation of a _species_ of art, comprehended as such, means for the life-history of a Culture. It is epochal. Apart from the merest externals, each such art is an individual organism without predecessor or successor. Its theory, technique and convention all belong to its character, and contain nothing of eternal or universal validity. When one of these arts is born, when it is spent, whether it dies or is transmuted into another, why this or that art is dominant in or absent from a particular Culture—all these are questions of Form in the highest sense, just as is that other question of why individual painters and musicians unconsciously avoid certain shades and harmonies or, on the contrary, show preferences so marked that authorship-attributions can be based on them. The importance of these groups of questions has not yet been recognized by theory, even by that of the present day. And yet it is precisely from this side, the side of their physiognomic, that the arts are accessible to the understanding. Hitherto it has been supposed—without the slightest examination of the weighty questions that the supposition involves—that the several “arts” specified in the conventional classification-scheme (the validity of which is assumed) are all _possible_ at all times and places, and the absence of one or another of them in particular cases is attributed to the accidental lack of creative personalities or impelling circumstances or discriminating patrons to guide “art” on its “way.” Here we have what I call a transference of the causality-principle from the world of the become to that of the becoming. Having no eye for the perfectly different logic and necessity of the Living, for Destiny and the inevitableness and _unique occurrence_ of its expression-possibilities, men had recourse to tangible and obvious “causes” for the building of their art-history, which thus came to consist of a series of events of only superficial concordance.