Plato's conception of the act of vision was--That fire darted forth from the eyes of the percipient and came into confluence or coalescence with fire approaching from the perceived object (Plato, Timæus, pp. 45 C, 67 C).] [Side-note: Agent and Patient--No absolute Ens.] Accordingly, nothing can be affirmed to exist separately and by itself. All existences, come only as twin and correlative manifestations of this double agency. In fact neither of these agencies can be conceived independently and apart from the other: each of them is a nullity without the other.[35] If either of them be varied, the result also will vary proportionally: each may be in its turn agent or patient, according to the different partners with which it comes into confluence.[36] It is therefore improper to say--Such or such a thing _exists_. Existence absolute, perpetual, and unchangeable is nowhere to be found: and all phrases which imply it are incorrect, though we are driven to use them by habit and for want of knowing better. All that is real is, the perpetual series of changeful and transient conjunctions; each Object, with a certain Subject,--each Subject, with a certain Object.[37] This is true not merely of individual objects, but also of those complex aggregates rationally apprehended which receive generic names, _man_, animal, stone, &c.[38] You must not therefore say that any thing _is_, absolutely and perpetually, good, honourable, hot, white, hard, great--but only that it is so felt or esteemed by certain subjects more or less numerous.[39] [Footnote 35: Plato, Theætêt. p. 157 A. [Greek: e)pei\ kai\ to\ poiou=n ei)=nai ti kai\ to\ pa/schon au)= ti e)pi\ e(no\s noê=sai, ô(/s phasin, ou)k ei)=nai pagi/ôs. Ou)/te ga\r poiou=n e)sti/ ti, pri\n a)\n tô=| pa/schonti xune/lthê|--ou)/te pa/schon, pri\n a)\n tô=| poiou=nti], &c.] [Footnote 36: Plato, Theætêt. p. 157 A. [Greek: to/ te/ tini xuneltho\n kai\ poiou=n a)/llô| au)= prospeso\n pa/schon a)nepha/nê.]] [Footnote 37: Plato, Theætêt. p. 157 A. [Greek: ou)de\n ei)=nai e(\n au)to\ kath' au(to/, a)lla/ tini a)ei\ gi/gnesthai, to\ d' ei)=nai panta/chothen e)xairete/on], &c.] [Footnote 38: Plato, Theætêt. p. 157 B. [Greek: dei= de\ kai\ kata\ me/ros ou(/tô le/gein kai\ peri\ pollô=n a)throisthe/ntôn, ô(=| dê\ a)throi/smati a)/nthrôpo/n te ti/thentai kai\ li/thon kai\ e(/kaston zô=o/n te kai\ ei)=dos.] In this passage I follow Heindorf's explanation which seems dictated by the last word [Greek: ei)=dos]. Yet I am not sure that Plato does really mean here the _generic_ aggregates. He had before talked about sights, sounds, hot, cold, hard, &c., the separate sensations. He may perhaps here mean simply individual things as aggregates or [Greek: a)throi/smata]--a _man_, a _stone_, &c.] [Footnote 39: Plato, Theætêt. p. 157 E.] [Side-note: Arguments derived from dreams, fevers, &c., may be answered.]