The principle of analogy

Since nonbeing cannot produce being (5) only being can product being. But a contingent being cannot produce another contingent being (6). And a necessary being cannot produce another necessary being (8).
So only Necessary Being can cause or produce only a contingent being. For to "cause" or "produce" being means to bring something into being. Something that comes into being, has being. A cause cannot bring nonbeing into being, since being is not nonbeing (4). The fact that Being produces being implies that there is an analogy between the cause of being and the being it causes (8). But a contingent being is both similar and different from a Necessary Being. It is similar in that both have being. It is different in that one is necessary and the other is contingent. But whatever is both similar and different is analogous. Hence, there is an analogy between Necessary Being and the being it produces.
Two things, then, are entailed in the principle that Necessary Being causes being: First, the effect must resemble the cause, since, both are being. The cause of being cannot produce what it does not posses. Second, while the effect must it must also be different from it in its potentiality. For the cause, by its very nature, has no potential not to be. But the effect by its very nature has the potential not to be. Hence, a contingent being must be different from its Cause. Since, the Cause of contingent beings must be both like and different from its effect, it is only similar. Hence, there is an analogical likeness between the Cause of a contingent being and the contingent being it causes to exist.
Such a Being is appropriately called "God" in the theistic sense, because he possesses all the essential characteristics of a theistic God; therefore, the theistic God exists.

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