2. The subject and predicate of a proposition, affirming the existence of something which is already come to pass, are fixed and certain.
3. The subject and predicate of a proposition may be fixed and certain consequentially,—and so the existence of the things affirmed may be “consequentially necessary.” “Things which are perfectly connected with the things that are necessary, are necessary themselves, by a necessity of consequence.” This is logical necessity.
“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,”—that is, “by a connexion with something that is necessary in its own nature, or something that already is or has been. This is the necessity which especially belongs to controversies about acts of the will.” (p. 30.)
Philosophical necessity is general and particular. 1. “The existence of a thing may be said to be necessary with a general necessity, when all things considered there is a foundation for the certainty of its existence.” This is unconditional necessity in the strictest sense.
2. Particular necessity refers to “things that happen to particular persons, in the existence of which, no will of theirs has any concern, at least at that time; which, whether they are necessary or not with regard to things in general, yet are necessary to them, and with regard to any volition of theirs at that time, as they prevent all acts of the will about the affair.” (p. 31.) This particular necessity is absolute to the individual, because his will has nothing to do with it—whether it be absolute or not in the general sense, does not affect his case.
“What has been said to show the meaning of terms necessary and necessity, may be sufficient for the explaining of the opposite terms impossible and impossibility. For there is no difference, but only the latter are negative and the former positive.” (ibid.)
Inability and Unable.
“It has been observed that these terms in their original and common use, have relation to will and endeavour, as supposable in the case.” That is have relation to the connexion of volition with effects. “But as these terms are often used by philosophers and divines, especially writers on controversies about free will, they are used in a quite different and far more extensive sense, and are applied to many cases wherein no will or endeavour for the bringing of the thing to pass is or can be supposed:” e. g. The connexion between volitions and their causes or motives.
Contingent and Contingency.
“Any thing is said to be contingent, or to come to pass by chance or accident, in the original meaning of such words, when its connexion with its causes or antecedents, according to the established course of things, is not discerned; and so is what we have no means of foreseeing. But the word, contingent, is abundantly used in a very different sense; not for that, whose connexion with the series of things we cannot discern so as to foresee the event, but for something which has absolutely no previous ground or reason, with which its existence has any fixed connexion.” (p. 31. 32.)