istence of the thing, but when the thing exists, it is not necessary that every cause should exist, still some cause indeed, yet not every cause. Or if the problem is always universal, is the cause also a certain whole, and that of which it is the cause universal? as to shed the leaf is present definitely with a certain whole, though there should be species of it, and with these universally, i. e. either with plants or with such plants. Hence in these, the medium and that of which it is the cause must be equal, and reciprocate, for instance, why do the trees shed their leaves? if indeed through the concretion of moisture, whether the tree casts its leaf, there must of necessity be concretion, or whether there is concretion not in any thing indiscriminately, but in a tree, the latter must necessarily shed its leaf.
Chapter 17
Whether however may there not be possibly the same cause of the same thing in all things, but a different one, or is this impossible? or shall we say it cannot happen, if it is demonstrated per se and not by a sign or accident? for the middle is the definition of the extreme, but if it is not thus, (shall we say that) it is possible? We may however consider that of which and to which
