Vitae philosophorum

The repetition at such length of all that we are now recalling to mind furnishes an adequate outline for our conception of the nature of things.

Moreover, there is an infinite number of worlds, some like this world, others unlike it.[*](This remark is not misplaced. For infinity of worlds follows from the infinity of (a) atoms, (b) space; see inf.§§ 73, 89; Lucr. ii. 1048 foll.) For the atoms being infinite in number, as has just been proved, are borne ever further in their course. For the atoms out of which a world might arise, or by which a world might be formed, have not all been expended on one world or a finite number of worlds, whether like or unlike this one. Hence there will be nothing to hinder an infinity of worlds.

Again, there are outlines or films, which are of the same shape as solid bodies, but of a thinness far exceeding that of any object that we see. For it is not impossible that there should be found in the surrounding air combinations of this kind, materials adapted for expressing the hollowness and thinness of surfaces, and effluxes preserving the same relative position and motion which they had in the solid objects from which they come. To these films we give the name of images or idols. Furthermore,

Not that, if we consider the minute times perceptible by reason alone,[*](Cf. Lucr. iv. 794-8: In one unit of time, when we can perceive it by sense and while one single word is uttered, many latent times are contained which reason finds to exist Obviously such minute times are immeasurably short. The unit of sensible time appears to be that called (in § 62) the minimum continuous time. Cf. Sext. Emp. x.§§ 148-154.) the moving body itself arrives at more than one place simultaneously (for this too is inconceivable), although in time perceptible to sense it does arrive simultaneously, however different the point of departure from that conceived by us. For if it changed its direction, that would be equivalent to its meeting with resistance, even if up to that point we allow nothing to impede the rate of its flight. This is an elementary fact which in itself is well worth bearing in mind. In the next place the exceeding thinness of the images is contradicted by none of the facts under our observation. Hence also their velocities are enormous, since they always find a void passage to fit them. Besides, their incessant effluence meets with no resistance,[*](Or, inserting τὸ, not τῷ, before τῷ ἀπείρῳ, a passage of the proper size to secure that nothing obstructs their endless emanation. But the meaning cannot be called certain.) or very little, although many atoms, not to say an unlimited number, do at once encounter resistance.

Besides this, remember that the production of the images is as quick as thought. For particles are continually streaming off from the surface of bodies, though no diminution of the bodies is observed, because other particles take their place.[*](If vision is to be not merely intermittent but continuous, images must be perpetually streaming from the objects seen to our eyes; there must be a continual succession of similar images. Cf. Fr. 282 (Us.); Lucr. ii. 67-76, iv. 143-167.) And those

We must also consider that it is by the entrance of something coming from external objects that we see their shapes and think of them.[*](Thought, as well as vision, is explained by images, but images of a much finer texture, which fail to affect the eyes but do affect the mind: cf. Fr. 317 (Us.); Lucr. iv. 777 f.) For external things would not stamp on us their own nature of colour and form through the medium of the air which is between them and us,[*](This was the view of Democritus; cf. Beare, Greek Theories of Elementary Cognition, p. 26.) or by means of rays of light or currents of any sort going from us to them, so well as by the entrance into our eyes or minds, to whichever their size is suitable, of certain films coming from the things themselves, these films or outlines being of the same colour and shape as the external things themselves.

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