16. An Ideal-Principle approaches and leads Matter towards some desired dimension, investing this non-existent underlie with a magnitude from itself which never becomes incorporate- for Matter, if it really incorporated magnitude, would be a mass.
Eliminate this Ideal-Form and the substratum ceases to be a thing of magnitude, or to appear so: the mass produced by the Idea was, let us suppose, a man or a horse; the horse-magnitude came upon the Matter when a horse was produced upon it; when the horse ceases to exist upon the Matter, the magnitude of the horse departs also. If we are told that the horse implies a certain determined bulk and that this bulk is a permanent thing, we answer that what is permanent in this case is not the magnitude of the horse but the magnitude of mass in general. That same Magnitude might be fire or earth; on their disappearance their particular magnitudes would disappear with them. Matter, then, can never take to itself either pattern or magnitude; if it did, it would no longer be able to turn from being fire, let us say, into being something else; it would become and be fire once for all.
In a word, though Matter is far extended- so vastly as to appear co-extensive with all this sense-known Universe- yet if the Heavens and their content came to an end, all magnitude would simultaneously pass from Matter with, beyond a doubt, all its other properties; it would be abandoned to its own Kind, retaining nothing of all that which, in its own peculiar mode, it had hitherto exhibited.
Where an entrant force can effect modification it will inevitably leave some trace upon its withdrawal; but where there can be no modification, nothing can be retained; light comes and goes, and the air is as it always was.
That a thing essentially devoid of magnitude should come to a certain size is no more astonishing than that a thing essentially devoid of heat should become warm: Matter's essential existence is quite separate from its existing in bulk, since, of course, magnitude is an immaterial principle as pattern is. Besides, if we are not to reduce Matter to nothing, it must be all things by way of participation, and Magnitude is one of those all things.
In bodies, necessarily compounds, Magnitude though not a determined Magnitude must be present as one of the constituents; it is implied in the very notion of body; but Matter- not a Body- excludes even undetermined Magnitude.