In what sense then, let us inquire, does the knowledge of a present event prove it to be necessary? It is necessary, says Edwards, because it is indissolubly connected with the knowledge of it. In other words, it could not possibly be known to exist, unless it did exist; and hence, its existence is said to be indissolubly connected with the knowledge of its existence, or, in other words, it is said to be necessary. This is all true; but is this indissoluble connexion, or necessity, at all inconsistent with the contingency of the event known? This is the question; and let us not lose sight of it in a mist of words. Let it be distinctly borne in mind, and it will be easily settled.
For this purpose, let us suppose, to adopt the language of President Edwards, “that nonentity is about to bring forth;” and that an event comes into being without any cause of its existence. This event then exists; it is seen, and it is known to exist. Now, even on this wild supposition, there is an infallible and indissoluble connexion between the existence of the event and the knowledge of it; and hence it is necessary, in the sense above explained. But what has this necessary connexion to do with the cause of its existence? This indissoluble connexion, this dire necessity, is perfectly consistent, as we have seen, with the supposition that the event had no cause at all of its existence. How can it conflict, then, with any scheme of free-agency that ever was dreamed of by man?
If this argument proves any thing in regard to human actions, it only proves that a volition has an effect, and not that it has a cause. Indeed, it has been said, that the knowledge of an event is the effect of its existence; and the same remark has been extended to the foreknowledge of God with respect to the future volitions of human beings. This position is not denied by Edwards; he considers, in fact, that it strengthens, rather than weakens, his argument. “Because it shows the existence of the event to be so settled and firm, that it is as if it had already been; inasmuch as in effect it actually exists already;” and much more to the same purpose, p.122-3. “It is as strong arguing,” says he, “from the effect to the cause, as from the cause to the effect.”
This is all true; it is as strong arguing from effect to cause, as it is from cause to effect. But do the arguments prove the same thing? Let us see. I know a thing to exist; and therefore it does exist. This is to reason from effect to cause. The conclusion is inevitable; but what does it prove? Why, it proves that the thing does exist—it proves the bare fact of existence. The indissoluble connexion, or the necessity, in this case, exists between the knowledge and the event known; and it has no relation to the question how the event came to exist. This argument, then, in regard to human volitions, only proves that they are indissolubly connected with their effects, and are necessarily implied by them; just as every cause is implied by its effects: but no libertarian in the world has ever questioned such a position. For all that such an argument proves, all the volitions of moral agents may come into existence, without having the least shadow of reason or ground of their existence. We admit that volitions are efficient causes; and that they have effects, with which they are indissolubly connected. Edwards undertook to show, that volitions are necessary, because they are infallibly and indissolubly connected with their causes; and he has shown that they are necessary, because they are infallibly and indissolubly connected with their effects! This is one branch of his great argument.
There is another sense, in which the knowledge of an event, whether it be fore, or after, or concomitant, knowledge, proves it to be necessary. This sense is not clearly distinguished from the former by Edwards. He recognizes them both, however, although he blends them together, and frequently turns from the one to the other in the course of his argument. It is highly important, and affords no little satisfaction, to keep them clearly distinct in our minds.
A thing is said to be necessary, as we have seen, because it is connected with the knowledge of it; and, if a thing does exist, or is certainly and infallibly known to exist, it may be said to be necessary, on the principle that it is impossible it should exist and not exist at one and the same time. These two things are evidently different; and, for the sake of distinctness in our language, as well as in our thoughts, I shall call the first a logical, and the last an axiomatical necessity. A thing, then, which does exist, is said to be necessary with an axiomatical necessity; because it is impossible for it not to exist while it does exist: and it is said to be necessary, with a logical necessity, because it is indissolubly connected with the knowledge of it. The former kind of necessity is frequently presented in this form of expression, that if a thing does exist, it is impossible it should be otherwise than true that it does exist. In this form of expression, it is frequently resorted to by Edwards.
Thus, says he, “I observed before, in explaining the nature of necessity, that in things which are past, their past existence is now necessary; having already made sure of existence, it is now impossible that it should be otherwise than true, that the thing has existed,” p. 114-15. Just so we may say in relation to things which now exist; for, having already made sure of existence, it is impossible it should be otherwise than true, that they do now exist; or, in other words, it is impossible they should not exist while they do exist. In like manner, if the future existence of any thing is foreknown, “it is impossible it should be otherwise than true,” that it should exist, or come to pass: that is to say, if it will exist, it will be impossible for it not to exist at the time of its existence.
Foreknowledge, I admit, infers this kind of necessity; but is this any thing to the purpose? The conclusion is the same, whether it be deduced from foreknowledge, or concomitant knowledge. Let us suppose, then, for the sake of clearness and convenience, that a thing is now known to exist. It follows from hence, by a logical necessity, that it does exist; for it could not possibly be known to exist, unless it did exist. And, as it does exist, “it is impossible that it should be otherwise than true that it does exist;” or, in other words, it is impossible for it not to exist now, while it does exist. This is all there is in this part of the argument.
And what does it amount to? It is a simple declaration of what no body ever denied—that if a thing exists, or is to exist, or has existed, it is impossible to conceive of it as not existing at the time of its existence. All this is perfectly true, without the least reference to the question, how it came to exist, or how it will come to exist? It is wholly irrelevant to the point at issue. It controverts no position, held by any sane man that now lives, or that ever has lived.
In other words, if a thing is known to exist, certainly and infallibly, then it does exist; and if it does exist, then “it is impossible it should be otherwise than true” that it does exist; and hence its existence is said to be necessary with an axiomatical necessity. But this does not prove that it is necessarily produced. For, supposing it to exist, its existence would be necessary in the above sense, even if it had no cause of its existence. The necessity here referred to, is a necessity in the order of our ideas, and not in the course of events. It arises from the impossibility of a thing’s not existing at the time it does exist; and it has no reference whatever to the causation of any thing: it is a fundamental law of belief, and not a causal necessity. These three things, an axiomatical, a logical, and a causal necessity, are most strangely confounded in the argument of President Edwards.