Section III (continued)
Concerning the meaning of the terms, Necessity, Impossibility, Inability, &c. and of Contingence.
I will now try to show that necessity is not inconsistent with liberty. Before proceeding, however, I will give my definition of the word “necessity.” What I mean when I use the term is the complete and certain connection between the subject and predicate of a given proposition.
“The subject and predicate of a proposition, which affirms the existence of something, may have a full, fixed, and certain connection several ways.”
(1.) The full and perfect connection may be inherent in the nature of the things themselves and any supposition to the contrary would be a contradiction or “gross absurdity.” For instance, “the eternal existence of being” is necessary in itself; it would be the “greatest absurdity” to deny the existence of being (would space allow, this could be shown to be “the sum of all contradictions”). The attributes of God, including his infinity, are, in this same sense, necessary. It is also necessary in itself that 2+2=4 and that all lies extending from the center of a circle to its edge are equal in length. Other 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 certainty of connection may come from the fact that the thing “is already come to pass” and has been “made sure of existence.” Therefore, a claim that acknowledges both present and past existence of it, is, in that way, made unalterably true. The “existence of whatever is already come to pass, is now become necessary.”
(3.) The connection might also be necessary as a consequence of something that is necessary in one of the ways discussed above [i.e., in previous posts]. This type of necessity hinges on the connection of two or more propositions with each other. Something that is “perfectly connected” with something that is already established as necessary is necessary “by a Necessity of consequence.”
It is only in this last sense that we can call something in the future necessary. It cannot be inherently necessary in itself, or else it would already exist. Likewise, for anything in the past (except those which were from eternity) this is the only sense in which they “could be necessary before they came to pass.” Therefore, this is the only way that any effect or event (anything that had, in the past, a beginning or will have one in the future) “has come into being necessarily. This is the Necessity we must focus on in questions about the acts of the will.
Furthermore we can distinguish between general and particular Necessity. A thing’s existence falls under general Necessity when “there is a foundation for the certainty of their existence” or where there is a complete and certain connection between “the subject and predicate of the proposition which affirms its existence.”
Something is necessary with particular Necessity when there is nothing that can affect the certainty of an event or the existence of a thing. With a particular Necessity nothing “can be of any account at all, in determining the infallibility of the connection of the subject and predicate in the proposition which affirms the existence of things.” So there are things that happen to particular people despite the fact that (at least at that time) their will does not affect its existence. Regardless of whether such things carry a general Necessity, yet they are necessary to those particular people “as they prevent all acts of the will about the affair.” It may be true that the same thing is necessary both in the general sense and in the particular sense, but that does not alter the case for drawing this distinction in the first place.
All of this should be sufficient for explaining how the terms “necessary” and “Necessity” are used as terms of art by metaphysicians and others. They assign a more extensive definition that either the original meanings or common usages of those words.
What I have said to explain “necessary” and “necessity” may also be sufficient for explaining the opposite terms: impossible and impossibility. The only difference is that the former are positive while the latter are negative. Impossibility is negative necessity or “a Necessity that a thing should not be.” It is also used as a term of art, distinct from its original, common meaning.
The same can be said for the words “unable” and “inability.” It has been pointed out that these words were originally used in relation to will and endeavor and as falling short of being able to bring to pass the thing willed or endeavored. When it comes to more philosophical writing, however (“especially writers on controversies about Free Will”), they are used very differently, even in cases where no will or endeavors “is or can be supposed.”
Just as all these words (necessary, impossible, unable, etc.) are used by some writers in ways that go beyond their common meaning, the same has happened to the term “contingent.” In its original sense, a thing was contingent if “its connection with its causes or antecedents . . . is not discerned.” With regard to us, something is deemed contingent or accidental if “it comes to pass without our foreknowledge, and besides our design and scope.”
However, the word “contingent” is frequently used in a very different sense. Rather than referring to something we cannot foresee, it is used to refer to “something which has absolutely no previous ground or reason.”