It is manifest that all such like words and phrases, as vulgarly used, are understood in this manner. A thing is said to be necessary, when we cannot help it, let us do what we will. So any thing is said to be impossible to us, when we would do it, or would have it brought to pass, and endeavor it; or at least may be supposed to desire and seek it; but all our desires and endeavors are, or would be, vain. And that is said to be irresistible, which overcomes all our opposition, resistance, and endeavor to the contrary. And we are said to be unable to do a thing when our supposable desires and endeavors are insufficient.
We are accustomed, in the common use of language, thus to apply and understand these phrases: we grow up with such a habit; which, by the daily use of these terms from our childhood, becomes fixed and settled; so that the idea of a relation to a supposed will, desire, and endeavor of ours, is strongly connected with these terms, whenever we hear the words used. Such ideas, and these words, are so associated, that they unavoidably go together; one suggests the other, and never can be easily separated as long as we live. And though we use the words, as terms of art, in another sense, yet, unless we are exceedingly circumspect, we shall insensibly slide into the vulgar use of them, and so apply the words in a very inconsistent manner, which will deceive and confound us in our reasonings and discourses, even when we pretend to use them as terms of art.
4. It follows from what has been observed, that when these terms necessary, impossible, irresistible, unable, &c. are used in cases wherein no insufficient will is supposed, or can be supposed, but the very nature of the supposed case itself excludes any opposition, will, or endeavor; they are then not used in their proper signification. The reason is manifest; in such cases we cannot use the words with reference to a supposable opposition, will, or endeavor. And therefore if any man uses these terms in such cases, he either uses them nonsensically, or in some new sense, diverse from their original and proper meaning. As for instance; if any one should affirm after this manner, That it is necessary for a man, or what must be, that he should choose virtue rather than vice, during the time that he prefers virtue to vice; and that it is a thing impossible and irresistible, that it should be otherwise than that he should have this choice, so long as this choice continues; such a one would use the terms must, irresistible, &c. with either perfect insignificance, or in some new sense, diverse from their common use; which is with reference, as has been observed, to supposable opposition, unwillingness, and resistance; whereas, here, the very supposition excludes and denies any such thing: for the case supposed is that of being willing, and choosing.
5. It appears from what has been said, that these terms necessary, impossible, &c. are often used by philosophers and metaphysicians in a sense quite diverse from their common and original signification; for they apply them to many cases in which no opposition is supposable. Thus they use them with respect to God’s existence before the creation of the world, when there was no other being; with regard to many of the dispositions and acts of the divine Being, such as his loving himself, his loving righteousness, hating sin, &c. So they apply them to many cases of the inclinations and actions of created intelligent beings wherein all opposition of the Will is excluded in the very supposition of the case.
Metaphysical or philosophical Necessity is nothing different from their certainty. I speak not now of the certainty of knowledge, but the certainty that is in things themselves, which is the foundation of the certainty of the knowledge, or that wherein lies the ground of the infallibility of the proposition which affirms them.
What is sometimes given as the definition of philosophical Necessity, namely, ”That by which a thing cannot but be,“ or ”whereby it cannot be otherwise,” fails of being a proper explanation of it, on two accounts: First, the words can, or cannot, need explanation as much as the word Necessity; and the former may as well be explained by the latter, as the latter by the former. Thus, if any one asked us what we mean, when we say, a thing cannot but be, we might explain ourselves by saying, it must necessarily be so; as well as explain Necessity, by saying, it is that by which a thing cannot but be. And Secondly, this definition is liable to the fore-mentioned great inconvenience; the words cannot, or unable, are properly relative, and have relation to power exerted, or that may be exerted, in order to the thing spoken of; to which as I have now observed, the word Necessity, as used by philosophers, has no reference.
Philosophical Necessity is really nothing else than the full and fixed connexion between the things signified by the subject and predicate of a proposition, which affirms something to be true. When there is such a connexion, then the thing affirmed in the proposition is necessary, in a philosophical sense; whether any opposition or contrary effort be supposed, or no. When the subject and predicate of the proposition, which affirms the existence of any thing, either substance, quality, act, or circumstance, have a full and certain connexion, then the existence or being of that thing is said to be necessary in a metaphysical sense. And in this sense I use the word necessity, in the following discourse, when I endeavor to prove that necessity is not inconsistent with liberty.
The subject and predicate of a proposition, which affirms existence of something, may have a full, fixed, and certain connexion several ways.
(1.) They may have a full and perfect connexion in and of themselves; because it may imply a contradiction, or gross absurdity, to suppose them not connected. Thus many things are necessary in their own nature. So the eternal existence of being generally considered, is necessary in itself: because it would be in itself the greatest absurdity, to deny the existence of being in general, or to say there was absolute and universal nothing; and is as it were the sum of all contradictions; as might be shown if this were a proper place for it. So God’s infinity and other attributes are necessary. So it is necessary in its own nature, that two and two should be four; and it is necessary that all right lines drawn from the center of a circle to the circumference should be equal. It is necessary, fit and suitable, that men should do to others, as they would that they should do to them. So innumerable metaphysical and mathematical truths are necessary in themselves: the subject and predicate of the proposition which affirm them, are perfectly connected of themselves.
(2.) The connexion of the subject and predicate of a proposition, which affirms the existence of something, may be fixed and made certain, because the existence of that thing is already come to pass; and either now is, or has been; and so has, as it were, made sure of existence. And therefore, the proposition which affirms present and past existence of it, may by this means be made certain, and necessarily and unalterably true; the past event has fixed and decided the matter, as to its existence; and has made it impossible but that existence should be truly predicated of it. Thus the existence of whatever is already come to pass, is now become necessary; it is become impossible it should be otherwise than true, that such a thing has been.
(3.) The subject and predicate of a proposition which affirms something to be, may have a real and certain connexion consequentially; and so the existence of the thing may be consequentially necessary; as it may be surely and firmly connected with something else, that is necessary in one of the former respects. As it is either fully and thoroughly connected with that which is absolutely necessary in its own nature, or with something which has already received and made sure of existence. This Necessity lies in, or may be explained by, the connexion of two or more propositions one with another.—Things which are perfectly connected with other things that are necessary, are necessary themselves, by a Necessity of consequence.
And here it may be observed, that all things which are future, or which will hereafter begin to be, which can be said to be necessary, are necessary only in this last way. Their existence is not necessary in itself; for if so, they always would have existed. Nor is their existence become necessary by being already come to pass. Therefore, the only way that any thing that is to come to pass hereafter, is or can be necessary, is by a connexion with something that is necessary in its own nature, or something that already is, or has been; so that the one being supposed the other certainly follows.—And this also is the only way that all things