How then do matters stand between art and civilisation? Here follows my hypothesis. There is in the history of every art (and for brevity's sake, I include in this term every distinct category, say, renaissance sculpture as distinguished from antique, of the same art) a moment when, for one reason or other, that art begins to come to the fore, to bestir itself. The circumstances of the nation and time make this art materially advantageous or spiritually attractive; the opening up of quarries, the discovery of metallic alloys, the necessity of roofing larger spaces, the demand for a sedentary amusement, for music to dance to in new social gatherings--any such humble reason, besides many others, can cause one art to issue more particularly out of the limbo of the undeveloped, or out of the lumber-room of the unused.
It is during this historic moment--a moment which may last years or scores of years--that, as it seems to me, an art can really be deeply affected by its surrounding civilisation. For is it not called forth by that civilisation's requirements, material or spiritual; and is it not, by the very fact of being thus new, or at all events nascent, devoid of all conditioning factors, save those which the civilisation and its requirements impose from without? An art, like everything vital, takes shape not merely by pressure from without, but much more by the necessities inherent in its own constitution, the almost mechanical necessities by which all variable things _can_ vary only in certain fashions. All the natural selection, all the outer pressure in the world, cannot make a stone become larger by cutting, cannot make colour less complex by mixing, cannot make the ear perceive a dissonance more easily than a consonance, cannot make the human mind turn back from problems once opened up, or revert instantaneously to effects it is sick of; and a number of such immutable necessities constitute what we call the organism of an art, which can therefore respond only in one way and not another to the influences of surrounding civilisation. Given the sculpture of the Ægina period, it is impossible we should not arrive at the sculpture of the time of Alexander: the very constitution of clay and bronze, of marble, chisel and mallet, let alone that of the human mind, makes it inevitable; and you would have it inevitably if you could invert history, and put Chæronea in the place of Salamis. But there is no reason why you should eventually get Lysippian and Praxitelean sculpture instead of Egyptian or Assyrian, say, in the time of Homer, whenever that may have been. For the causes which forced Greek sculpture along the line leading to Praxiteles and Lysippus were not yet at work; and had other forces, say, a preference for stone work instead of clay and bronze work, a habit of Persian or Gaulish garments, of Lydian effeminate life instead of Dorian athleticism, supervened, had satraps ordered rock-reliefs of battles instead of burghers ordering brazen images of boxers and runners, Praxiteles and Lysippus might have remained _in mente Dei_, if, indeed, even there. Similarly, once given your Pisan sculptors, Giotto, nay, your imaginary Cimabue, you inevitably get your Donatello, Masaccio, Ghirlandajo, and eventually your Leonardo, Michelangelo, and Titian; for the problems of form and of sentiment, the questions of perspective, anatomy, dramatic expression, lyric suggestion, architectural decoration, were established, in however rudimentary a manner, as soon as painting was ordered to leave off doing idle, emotionless Christs, rows of gala saints and symbols of metaphysic theology, and told to set about showing the episodes of Scripture, the things Christ and the Apostles did, and the places where they did them, and the feelings they felt about it all; told to make visible to the eye the gallant archangels, the lovable Madonnas, the dear little baby Saviours, the angels with their flowers and songs, all the human hope and pity and passion and tenderness which possessed the world in the days of St. Francis.