We have said nothing of the aesthetic problem of simple tone and colour. Though Plato, and even Hegel, discussed these, it is generally accepted to-day that they do not in fact exist in isolation from other suggestions. They always derive a value from their suggested relations and cannot be conceived apart from these. Such aesthetic value as clear tones and colours have is due to the fact that the elements they suggest and imply are few, like a sunset sky, and therefore they do not demand any great degree of elimination in the mind of the observer. Neither have we dealt with the problem of the relative importance of colour and form, except implicitly. The essential factor here is, of course, that colour does not exist _per se_. You cannot isolate a thing from its colour, in aesthetic intuition. To begin with, colour is the basis of visual perception, for the light by means of which the eye perceives an object must be of some definite series of wave-lengths of certain amplitudes balanced against one another in some definite manner through the selective absorption of that object, and wave-length is the physical basis of colour. Then, secondly, colour belongs to, and is an integral part of form. Form is not mere shape; it is determined by tone (or wave-amplitude) and colour (or wave-frequency) as well as by outline; and these are essential factors in the unity and order of the whole, and so are essential factors of the intuition. What we have said, then, of symmetry and geometric form, and of clearness of expression, together with what we have said of the elimination that is involved in aesthetic intuition, really covers the problem. Together, yet each in its own way, colour and form arouse in us the sense of unity and appeal to us as being in harmony with the intuition derived from other particulars; that in the world, under all its apparent multiplicity, there subsists a unity which relates all things together. CAMBRIDGE: PRINTED BY J. B. PEACE, M.A., AT THE UNIVERSITY PRESS. FOOTNOTES: [1] Bosanquet, _Hist. Aesth._ p. 18. [2] _Ibid._ p. 148. [3] G. Vico, _Scienza nuova seconda, Elementi liii_, quoted in Croce’s _Aesthetic_. [4] Bosanquet, _Hist. Aesth._ p. 267, _seq._ [5] Croce, _Aesthetic_, trs. Ainslie, p. 303. [6] Wildon Carr, _The Philosophy of Croce_, p. 97. [7] The clearest summary of Croce’s position is to be found in the brief third section of the first part of his _Philosophy of the Practical_. Prof. Wildon Carr also has given a very clear account of Croce’s philosophy as a whole in his book on _The Philosophy of Benedetto Croce_. [8] _Philosophy of the Practical_, p. 591. [9] _Philosophy of the Practical_, pp. 258-261. [10] This is not to condemn programme music altogether, for much of the best programme music does not attempt to paint a scene in such a way as to call up visual images. _Vide infra._