The word _matter_ is used analogically in many other senses, which are given by our lexicographers, who, however, omit to mention matter as that potency which receives its first existence through the substantial form. Webster says: "Matter is usually divided by philosophical writers into three kinds or classes: solid, liquid, and aeriform." This statement is not correct. Philosophical writers admit that _bodies_ are either solid, liquid, or aeriform; but they do not admit that the matter of which bodies and their molecules are made up is either solid, or liquid, or aeriform. Ice is solid, water is liquid, and vapor is aeriform; and yet the matter in all of them is identically the same. It is impossible, therefore, for philosophical writers to divide _matter_ into liquid, solid, and aeriform. The philosophical division of matter has always been into _materia informis_, or _prima_, or _actuabilis_--that is, matter conceived as void of all substantial form; and _materia formata_, or _secunda_, or _actuata_--that is, matter actuated by, and existing under, a substantial form. As I am not now writing a treatise on matter, I will dismiss this subject with only two observations. The first is, that the words _first matter_ and _second matter_ are indispensable in metaphysics, and, therefore, must be adopted in our English philosophical language, unless, indeed, we prefer to make use of the original Latin words. The other is, that in reading the metaphysical works of the scholastics, when we find the word _materia_ with the epithet _prima_, we should carefully ascertain that the epithet is not misapplied. For, it has been observed with reason that most of the abstruseness and uncertainty inherent in the old explanation of physical questions arises from the fact that the matter, which was supposed to be actually under its form, and therefore in act, was very frequently called _materia prima_, though it is known that "nothing that is in act can be called by such a name."[74] This observation is of the greatest importance, since it is evident that nothing but perpetual confusion can arise from contradictory definitions.