Chap. IX.—Of the Senses and Their Power.

It pleases me in this place to censure the folly of those who, while they wish to show that the senses are false, collect many instances in which the eyes are deceived; and among them this also, that all things appear double to the mad and intoxicated, as though the cause of that error were obscure. For it happens on this account, because there are two eyes. But hear how it happens. The sight of the eyes consists in the exertion of the soul. Therefore, since the mind, as has been above said, uses the eyes as windows, this happens not only to those who are intoxicated or mad, but even to those who are of sound mind, and sober. For if you place any object too near, it will appear double, for there is a certain interval and space in which the sight of the eyes meets together. Likewise, if you call the soul back as if to reflection, and relax the exertion of the mind, then the sight of each eye is drawn asunder, and they each begin to see separately.  

If you, again, exert the mind and direct the eyesight, whatever appeared double unites into one. What wonder, therefore, if the mind, impaired by poison and the powerful influence of wine, cannot direct itself to seeing, as the feet cannot to walking when they are weak through the numbness of the sinews, or if the force of madness raging against the brain disunites the agreement of the eyes? Which is so true, that in the case of one-eyed61    Luscis.   men, if they become either mad or intoxicated, it can by no means happen that they see any object double. Wherefore, if the reason is evident why the eyes are deceived, it is clear that the senses are not false: for they either are not deceived if they are pure and sound; or if they are deceived, yet the mind is not deceived which recognises their error.  

CAPUT IX. De sensibus eorumque vi.

Libet hoc loco illorum reprehendere vanitatem, qui dum volunt ostendere sensus falsos esse, multa colligunt, in quibus oculi fallantur; inter quae illud etiam, quod furiosis et ebriis omnia duplicia videantur: quasi vero ejus erroris obscura sit causa. Ideo enim fit, quia duo sunt oculi. Sed quomodo id fiat, accipe. Visus oculorum intentione animi constat. Itaque quoniam mens (ut supra dictum est) oculis tanquam fenestris utitur, non tantum hoc ebriis aut insanis 0040A accidit, sed et sanis, ac sobriis. Nam si aliquid nimis propius admoveas, duplex videbitur; certum est enim intervallum, ac spatium, quo acies oculorum coït. Item si retrorsum avoces animum, quasi ad cogitandum, et intentionem mentis relaxes, tum acies oculi utriusque diducitur, tunc singuli videre incipiunt separatim.

Si animum rursus intenderis, aciemque direxeris, coit in unum quidquid duplex videbatur. Quid ergo mirum, si mens veneno, ac potentia vini dissoluta, dirigere se non potest ad videndum, sicut ne pedes quidem ad ambulandum, nervis stupescentibus debiles? aut si vis furoris in cerebrum saeviens concordiam disjungit oculorum? Quod adeo verum est, ut luscis hominibus, si aut insani, aut ebrii fiant, nullo 0040B modo possit accidere, ut aliquid duplex videant. Quare si ratio apparet, cur oculi fallantur, manifestum est non esse falsos sensus; qui aut non falluntur, si sunt puri et integri, aut si falluntur, mens tamen non fallitur, quae illorum novit errorem.