_The Necessity of All Things_ In nature there is nothing contingent, but all things are determined from the necessity of the divine nature to exist and act in a certain manner.... That which has not been thus determined by God cannot determine itself to action. A thing which has been determined by God to any action cannot render itself indeterminate. ... All things have necessarily followed from the given nature of God and from the necessity of His nature have been determined to existence and action in a certain manner. If therefore things could have been of another nature, or could have been determined in another manner to action, so that the order of nature would have been different, the nature of God might then be different to that which it now is, and hence that different nature would necessarily exist, and there might consequently be two or more Gods, which is absurd. Therefore things could be produced by God in no other manner and in no other order than that in which they have been produced. Since I have thus shown, with greater clearness, than that of noonday light, that in things there is absolutely nothing by virtue of which they can be called contingent, I wish now to explain in a few words what is to be understood by _contingent_, but, firstly, what is to be understood by _necessary_ and _impossible_. A thing is called necessary either in reference to its essence or its cause. For the existence of a thing necessarily follows either from the essence and definition of the thing itself, or from a given efficient cause. In the same way a thing is said to be impossible either because the essence of the thing itself or its definition involves a contradiction, or because no external cause exists determinate to the production of such a thing. But a thing cannot be called contingent unless with reference to a deficiency in our knowledge. For if we do not know that the essence of a thing involves a contradiction, or if we actually know that it involves no contradiction, and nevertheless we can affirm nothing with certainty about its existence because the order of causes is concealed from us, that thing can never appear to us either as necessary or impossible, and therefore we call it either contingent or possible.