2. This, however, raises a problem deserving investigation in itself: what has happened when a definite magnitude of water becomes air, and how do we explain the increase of volume? But for the present we must be content with the matter thus far discussed out of all the varied controversy accumulated on either side.
It remains for us to make out on our own account the true explanation of the phenomenon of mixing, without regard to the agreement or disagreement of that theory with any of the current opinions mentioned.
When water runs through wool or when papyrus-pulp gives up its moisture why is not the moist content expressed to the very last drop or even, without question of outflow, how can we possibly think that in a mixture the relation of matter with matter, mass with mass, is contact and that only the qualities are fused? The pulp is not merely in touch with water outside it or even in its pores; it is wet through and through so that every particle of its matter is drenched in that quality. Now if the matter is soaked all through with the quality, then the water is everywhere in the pulp.
"Not the water; the quality of the water."
But then, where is the water? and [if only a quality has entered] why is there a change of volume? The pulp has been expanded by the addition: that is to say it has received magnitude from the incoming substance but if it has received the magnitude, magnitude has been added; and a magnitude added has not been absorbed; therefore the combined matter must occupy two several places. And as the two mixing substances communicate quality and receive matter in mutual give and take so they may give and take magnitude. Indeed when a quality meets another quality it suffers some change; it is mixed, and by that admixture it is no longer pure and therefore no longer itself but a blunter thing, whereas magnitude joining magnitude retains its full strength.
But let it be understood how we came to say that body passing through and through another body must produce disintegration, while we make qualities pervade their substances without producing disintegration: the bodilessness of qualities is the reason. Matter, too, is bodiless: it may, then, be supposed that as Matter pervades everything so the bodiless qualities associated with it- as long as they are few- have the power of penetration without disintegration. Anything solid would be stopped either in virtue of the fact that a solid has the precise quality which forbids it to penetrate or in that the mere coexistence of too many qualities in Matter [constitutes density and so] produces the same inhibition.
If, then, what we call a dense body is so by reason of the presence of many qualities, that plenitude of qualities will be the cause [of the inhibition].
If on the other hand density is itself a quality like what they call corporeity, then the cause will be that particular quality.
This would mean that the qualities of two substances do not bring about the mixing by merely being qualities but by being apt to mixture; nor does Matter refuse to enter into a mixing as Matter but as being associated with a quality repugnant to mixture; and this all the more since it has no magnitude of its own but only does not reject magnitude.
