The Argument from Contingency

“The third way is taken from possibility and necessity, and runs thus. We find in nature things that are possible to be and not to be, since they are found to be generated, and to corrupt, and consequently, they are possible to be and not to be. But it is impossible for these always to exist, for that which is possible not to be at some time is not. Therefore, if everything is possible not to be, then at one time there could have been nothing in existence. Now if this were true, even now there would be nothing in existence, because that which does not exist only begins to exist by something already existing. Therefore, if at one time nothing was in existence, it would have been impossible for anything to have begun to exist; and thus even now nothing would be in existence—which is absurd. Therefore, not all beings are merely possible, but there must exist something the existence of which is necessary. But every necessary thing either has its necessity caused by another, or not. Now it is impossible to go on to infinity in necessary things which have their necessity caused by another, as has been already proved in regard to efficient causes. Therefore we cannot but postulate the existence of some being having of itself its own necessity, and not receiving it from another, but rather causing in others their necessity. This all men speak of as God.”

“From this it is manifest that even by supposing the eternity of the world, we cannot escape the ultimate extramundane reason of things, that is to say, God. Accordingly the reasons of the world lie hid in something extramundane, different from the concatenation of states or the series of things, the aggregate of which constitutes the world.”

“Now this sufficient reason of the existence of the universe cannot be found in the sequence of contingent things … Thus the sufficient reason, which has no need of any other reason, must needs be outside of this sequence of contingent things and must be in a substance which is the cause of this sequence, or which is a necessary being, bearing in itself the reason of its own existence, otherwise we should not yet have a sufficient reason with which we could stop. And this ultimate reason of things is called God.”

“In such a chain, too, or succession of objects, each part is caused by that which preceded it, and causes that which succeeds it. Where then is the difficulty? But the whole, you say, wants a cause. I answer, that the uniting of these parts into a whole, like the uniting of several distinct countries into one kingdom, or several distinct members into one body, is performed merely by an arbitrary act of the mind, and has no influence on the nature of things.”

“The transcendental principle: "Everything that is contingent must have a cause"—a principle without significance, except in the sensuous world. For the purely intellectual conception of the contingent cannot produce any synthetical proposition, like that of causality … But in the present case it is employed to help us beyond the limits of its sphere.”