Page:Ferrier's Works Volume 3 "Philosophical Remains" (1883 ed.).djvu/363

Rh ," says he, "never formed the subject of controversy with any one. . . . That we see extension in two dimensions is admitted by all."—('Letter,' p. 10.) If it can be shown that the doctrine which is here stated to be admitted by all philosophers, is yet expressly controverted by the two metaphysicians whom Mr Bailey appears to have studied most assiduously, it is, at any rate, possible that he may have overlooked, in his own writings, the expression of an opinion which has escaped his penetration in theirs. To convince himself, then, how much he is mistaken in supposing that the visual intuition of longitudinal and lateral extension is admitted by all philosophers, he has but to turn to the works of Dr Brown and the elder Mill. In arguing that we have no immediate perception of visible figure, Dr Brown not only virtually, but expressly, asserts that the sight has no perception of extension in any of its dimensions. Not to multiply quotations, the following will, no doubt, be received as sufficient:—"They (i.e., philosophers) have—I think without sufficient reason—universally supposed that the superficial extension of length and breadth becomes known to us by sight originally." Dr Brown then proceeds to argue, with what success we are not at present considering, that our knowledge of extension and figure is derived from another source than the sense of sight.

Mr James Mill, an author whom Mr Bailey