—those that do not inherently warrant existence and whose nonexistence is not impossible—can exist only through a factor favoring their existence. Yet knowledge of this proposition is neither prior to nor more evident than knowledge of its individual instances. Whenever someone conceives that a particular thing does not inherently warrant existence and that its nonexistence is not impossible, he knows that this particular thing does not exist of itself. Indeed, merely conceiving of something as contingent entails this knowledge. For if it is said that a thing may exist, but that its existence is not of itself, or is not necessary of itself, this very conception entails that its existence comes from something other than itself.

The real issue is identifying which things are contingent. This may be known through their coming into being, whether directly observed or established by inference; thus, their method depends upon that of the former group. As for knowing this by some other method, that involves obscurities and disputes which this is not the place to discuss.