But, in man, there is not that necessity for the instinct, which exists in the peculiar situation of the other animals; and we find accordingly, that there is no trace of the instinct in him. It is long before the little nurseling shews, that his eye has distinguished objects from each other, so as to fix their place. We are able almost to trace in his efforts the progress which he is gradually making;—and, in those striking cases, which are sometimes presented to us, of the acquisition of sight, in mature life, in consequence of a surgical operation,—after vision had been obstructed from infancy,—it has been found, that the actual magnitude and figure, and position, of bodies, were to be learned like a new language,—that all objects seemed equally close to the eye,—and that a sphere and a cube, of each of which the tangible figure was previously known, were not so distinguishable in the mere sensation of vision, that the one could be said, with certainty, to be the cube, and the other the sphere. In short, what had been supposed, with every appearance of probability, was demonstrated by experiment,—that we learn to see,—and that vision is truly, what Swift has paradoxically defined it to be, the art of seeing things that are invisible.
Footnotes
[113] Essays—Inquiry concerning Human Understanding, Sect. xii. Part 2.
[114] Inquiry into the Human Mind, &c. Chap. v. Sect. 7.
[115] Darwin's Botanic Garden, Canto II. v. 203–6.
[116] Gray, de Princip. Cogit. lib. i. v. 85–96.
[117] Paradise Lost, Book III. v. 1–12.
[118] Ib. v. 38, 39.
[119] Ib. v. 40–41.
[120] Samson Agonistes, v. 93–97.