3. For the most convincing proof that vision does not depend upon the transmission of impressions of any kind made upon the air, we have only to consider that in the darkness of night we can see a fire and the stars and their very shapes.
No one will pretend that these forms are reproduced upon the darkness and come to us in linked progression; if the fire thus rayed out its own form, there would be an end to the darkness. In the blackest night, when the very stars are hidden and show no gleam of their light, we can see the fire of the beacon-stations and of maritime signal-towers.
Now if, in defiance of all that the senses tell us, we are to believe that in these examples the fire [as light] traverses the air, then, in so far as anything is visible, it must be that dimmed reproduction in the air, not the fire itself. But if an object can be seen on the other side of some intervening darkness, much more would it be visible with nothing intervening.
We may hold one thing certain: the impossibility of vision without an intervening substance does not depend upon that absence in itself: the sole reason is that, with the absence, there would be an end to the sympathy reigning in the living whole and relating the parts to each other in an existent unity.
Perception of every kind seems to depend on the fact that our universe is a whole sympathetic to itself: that it is so, appears from the universal participation in power from member to member, and especially in remote power.
No doubt it would be worth enquiry- though we pass it for the present- what would take place if there were another kosmos, another living whole having no contact with this one, and the far ridges of our heavens had sight: would our sphere see that other as from a mutually present distance, or could there be no dealing at all from this to that?
To return; there is a further consideration showing that sight is not brought about by this alleged modification of the intervenient.
Any modification of the air substance would necessarily be corporeal: there must be such an impression as is made upon sealing wax. But this would require that each part of the object of vision be impressed on some corresponding portion of the intervenient: the intervenient, however, in actual contact with the eye would be just that portion whose dimensions the pupil is capable of receiving. But as a matter of fact the entire object appears before the pupil; and it is seen entire by all within that air space for a great extent, in front, sideways, close at hand, from the back, as long as the line of vision is not blocked. This shows that any given portion of the air contains the object of vision, in face view so to speak, and, at once, we are confronted by no merely corporeal phenomena; the facts are explicable only as depending upon the greater laws, the spiritual, of a living being one and self-sensitive.