It often happens that the accidents of experience make us in this way introduce into the ideal, elements which, if they could be excluded without disgusting us, would make possible satisfactions greater than those we can now enjoy. Thus the taste formed by one school of art may condemn the greater beauties created by another. In morals we have the same phenomenon. A barbarous ideal of life requires tasks and dangers incompatible with happiness; a rude and oppressed conscience is incapable of regarding as good a state which excludes its own acrid satisfactions. So, too, a fanatical imagination cannot regard God as just unless he is represented as infinitely cruel. The purpose of education is, of course, to free us from these prejudices, and to develope our ideals in the direction of the greatest possible good. Evidently the ideal has been formed by the habit of perception; it is, in a rough way, that average form which we expect and most readily apperceive. The propriety and necessity of it is entirely relative to our experience and faculty of apperception. The shock of surprise, the incongruity with the formed percept, is the essence and measure of ugliness. _The average modified in the direction of pleasure._ Sec. 30. Nevertheless we do not form aesthetic ideals any more than other general types, entirely without bias. We have already observed that a percept seldom gives an impartial compound of the objects of which it is the generic image. This partiality is due to a variety of circumstances. One is the unequal accuracy of our observation. If some interest directs our attention to a particular quality of objects, that quality will be prominent in our percept; it may even be the only content clearly given in our general idea; and any object, however similar in other respects to those of the given class, will at once be distinguished as belonging to a different species if it lacks that characteristic on which our attention is particularly fixed. Our percepts are thus habitually biassed in the direction of practical interest, if practical interest does not indeed entirely govern their formation. In the same manner, our aesthetic ideals are biassed in the direction of aesthetic interest. Not all parts of an object are equally congruous with our perceptive faculty; not all elements are noted with the same pleasure. Those, therefore, which are agreeable are chiefly dwelt upon by the lover of beauty, and his percept will give an average of things with a great emphasis laid on that part of them which is beautiful. The ideal will thus deviate from the average in the direction of the observer's pleasure.