"Since the imagination is only the representation of the senses, it can only be pleased or displeased with the images, from the same principle on which the sense is pleased or displeased with the realities; and consequently there must be just as close an agreement in the imaginations as in the senses of men. "There are some men formed with feelings so blunt, with tempers so cold and phlegmatic, that they can hardly be said to be awake during the whole course of their lives. Upon such persons, the most striking objects make but a faint and obscure impression. There are others so continually in the agitation of gross and merely sensual pleasures, or so occupied in the low drudgery of avarice, or so heated in the chase of honors and distinction, that their minds, which had been used continually to the storms of these violent and tempestuous passions, can hardly be put in motion by the delicate and refined play of the imagination. These men, though from a different cause, become as stupid and insensible as the former; but whenever either of these happen to be struck with any natural elegance or greatness, or with these qualities in any work of art, they are moved upon the same principle." On a third point, Hume says: "But though there be naturally a wide difference in point of delicacy between one person and another, nothing tends farther to increase and improve this talent, than _practice_ in a particular art, and the frequent survey or contemplation of a particular species of beauty. "So advantageous is practice to the discernment of beauty, that, before we can give judgment on any work of importance, it will even be requisite that that very individual performance be more than once perused by us, and be surveyed in different lights with attention and deliberation." This is well illustrated by Burke, who observes: "It is known that the taste (whatever it is) is improved exactly as we improve our knowledge, by a steady attention to our object, and by frequent exercise. "To illustrate this--(that there is a difference, not in the causes, nor in the manner of men's being affected, but in the degree, owing to natural sensibility, or greater attention to the object)--to illustrate this by the procedure of the senses in which the same difference is found, let us suppose a very smooth marble-table to be set before two men; they both perceive it to be smooth, and they are both pleased with it because of this quality. So far they agree. "But suppose another, and after that another table, the latter still smoother than the former, to be set before them. It is now very probable that these men, who are so agreed upon what is smooth, and in the pleasure thence, will disagree when they come to settle which table has the advantage in point of polish.... Nor is it easy, when such a difference arises, to settle the point, if the excess or diminution be not glaring.