We ask again, What _are_ space and time? McCosh and Dr. Porter both answer: 1. They are not substances. This no one will dispute. They are not material substances having sensible qualities which can be the objects of sense perception. Space and time are not perceived by the senses.[103] Neither are they spiritual substances. We do not know them as having power and performing acts. 2. They both reply, They are not attributes or qualities of matter or spirit. This, also, no one will dispute, if the word "time" is not used as a synonym for "eternity," and the word "space" is not used as a synonym for "immensity," because "eternity" and "immensity" are attributes of the absolute Spirit. 3. They both assert, They are not relations. This is disputed by many: by Leibnitz, by Hamilton, by Saisset, by Calderwood, and by others. Leibnitz says, "Space is the order of things co-existing. Time is the order of things successive."[104] Hamilton says, "Space, like time, is only the intuition or the conception of a certain correlation of existence."[105] Calderwood defines time "as a certain correlation of existence," and "space as the recognized relation of extended objects."[106] And Saisset regards time and space as standing in the same category with mathematical relations.[107] These are, to say the least, distinguished names in philosophy. The opinions of men who have for years pondered these profound problems are at any rate entitled to proper consideration, and if in opposition to their views it is affirmed that time and space as understanding-concepts are _not_ relations, some reasons should be assigned. All the proof offered by Dr. McCosh is that "we know no two or more things which by their relation could yield space and time" (p. 211). We answer, promptly, _duration_ and _change_ do yield the relation of time. "The consciousness of succession in our mental states is in reality our consciousness of time."[108] The co-existence of two or more extended objects must yield the relation of space, for "empty space is nothing more than the relative distance of extended objects from each other, measured on a standard similar to that which applies to the bodies themselves. In this way it is equally accurate to say that there is a certain specified _distance_ between the bodies, and that there is _nothing_ between them, because space is nothing but their relation to each other."[109] Annihilate all finite existences, and what remains? Nothing but the immensity of God. Let one atom of matter be created, and we have extension. Let a second atom be created, and there is now a relation of distance, position, direction--that is, there is _space_.