After having settled his definition of choice or volition, and explained the cause of the same, Edwards takes up the nature of the connexion between this cause and effect: viz. motive and volition. Is this connexion a necessary connexion?
In order to determine this point, and to explain his view of it, he proceeds to discuss the meaning of the terms contained in the above title. This section is entirely occupied with this preliminary discussion.
Edwards makes two kinds of necessity: 1. Necessity as understood in the common or vulgar use; 2. Necessity as understood in the philosophical or metaphysical use.
1. In common use, necessity “is a relative term, and relates to some supposed opposition made to the existence of a thing, which opposition is overcome or proves insufficient to hinder or alter it. The word impossible is manifestly a relative term, and has reference to supposed power exerted to bring a thing to pass which is insufficient for the effect. The word unable is relative, and has relation to ability, or endeavour, which is insufficient. The word irresistible is relative, and has reference to resistance which is made, or may be made, to some force or power tending to an effect, and is insufficient to withstand the power or hinder the effect. The common notion of necessity and impossibility implies something that frustrates endeavour or desire.”
He then distinguishes this necessity into general and particular. “Things are necessary in general, which are or will be, notwithstanding any supposable opposition, from whatever quarter:” e. g. that God will judge the world.
“Things are necessary to us which are or will be, notwithstanding all opposition supposable in the case from us.” This is particular necessity: e. g. any event which I cannot hinder. In the discussions “about liberty and moral agency,” the word is used especially in a particular sense, because we are concerned in these discussions as individuals.
According to this common use of necessity in the particular sense, “When we speak of any thing necessary to us, it is with relation to some supposable opposition to our wills;” and “a thing is said to be necessary” in this sense “when we cannot help it, do what we will.” So also a thing is said to be impossible to us when we cannot do it, although we make the attempt,—that is, put forth the volition; and irresistible to us, which, when we put forth a volition to hinder it, overcomes the opposition: and we are unable to do a thing “when our supposable desires and endeavours are insufficient,”—are not followed by any effect. In the common or vulgar use of these terms, we are not considering volition in relation to its own cause; but we are considering volition as itself a cause in relation to its own effects: e. g. suppose a question be raised, whether a certain man can raise a certain weight,—if it be affirmed that it is impossible for him to raise it, that he has not the ability to raise it, and that the weight will necessarily keep its position,—no reference whatever is made to the production of a volition or choice to raise it, but solely to the connexion between the volition and the raising of the weight. Now Edwards remarks, that this common use of the term necessity and its cognates being habitual, is likely to enter into and confound our reasonings on subjects where it is inadmissible from the nature of the case. We must therefore be careful to discriminate. (p. 27.)
2. In metaphysical or philosophical use, necessity is not a relative, but an absolute term. In this use necessity applies “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 endeavour.” (ibid.) Thus it is used “with respect to God’s existence before the creation of the world, when there was no other being.” “Metaphysical or philosophical necessity is nothing different from certainty,—not the certainty of knowledge, but the certainty of things in themselves, which is the foundation of the certainty of knowledge, or that wherein lies the ground of the infallibility of the proposition which affirms them. 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; and in this sense I use the word necessity, in the following discourse, when I endeavour to prove that necessity is not inconsistent with liberty.” (p. 27, 28, 29.)
“The subject and predicate of a proposition which affirms the existence of something, may have a full, fixed, and certain connexion, in several ways.”
“1. They, may have a full and perfect connexion in and of themselves. So God’s infinity and other attributes are necessary. So it is necessary, in its own nature, that two and two should be four.”