Book 10
1.50
They move with rapid motion;The reader is left to infer that, the more rapid the motion, the more continuous is the succession of fresh images. It is this uninterrupted train of images which guarantees the continued existence of the external object, just as their similarity or identity guarantees its oneness: cf. Lucr. iv. 87, 104 f., 189, 256 f., 714 f.; Cic. N.D. i. 105. and this again explains why they present the appearance of the single continuous object, and retain the mutual interconnexion which they had in the object, when they impinge upon the sense, such impact being due to the oscillation of the atoms in the interior of the solid object from which they come. And whatever presentation we derive by direct contact, whether it be with the mind or with the sense-organs, be it shape that is presented or other properties, this shape as presented is the shape of the solid thing, and it is due either to a close coherence of the image as a whole or to a mere remnant of its parts.The film suffers from obstacles especially in its passage through the air, and is sometimes torn into tatters. When these reach the eye, the result is faulty perception; e.g. a square tower appears round, and the like: cf. Lucr. iv. 353-363, 379-390. Falsehood and error always depend upon the intrusion of opinionCf.Fr. 247-254 (Us.); Lucr. iv. 462-468, 723-826. (when a fact awaits) confirmation or the absence of contradiction, which fact is afterwards frequently not confirmed (or even contradicted) [following a certain movement in ourselves connected with, but distinct from, the mental picture presented—which is the cause of error.]
