COMPOSITION AND DECOMPOSITION ARE NOT ALTERATIONS.
Shall we have to admit that composition and decomposition are movements which exist by themselves, and analyze alteration into them? Condensation is explained as undergoing an alteration; that means, as becoming composite. On the other hand, rarefaction is also explained as undergoing an alteration, namely, that of decomposition; when, for instance, one mingles water and wine, each of these two things becomes other than it was, and it is the composition which has operated the alteration. We will answer that here composition and decomposition no doubt precede certain alterations, but these alterations are something different than compositions and decompositions. Other alterations (certainly) are not compositions and decompositions, for neither can condensation nor rarefaction be reduced to these movements, nor are they composed of them. Otherwise, it would be necessary to acknowledge the (existence of) emptiness. Besides, how could you explain blackness and whiteness, as being composed of composition and decomposition? This doctrine would destroy all colors and qualities, or at least, the greater part of them; for if all alteration, that means, all change of quality, consisted in a composition or decomposition, the result would not be the production of a quality, but an aggregation or disaggregation. How indeed could you explain the movements of teaching and studying by mere "composition"?