NECESSITY, whatever is done by a necessary cause, or a power that is irre sistible, in which sense it stands opposed to freedom.
NECasSITY, philosophical. The advo cates of philosophical necessity maintain, that the volition and actions of intelli gent agents are produCed by causes, equally deciding and resistless as those which are admitted to actuate the mate rial system of the universe. Wherever the sun shines, or the rain descends, it is impossible to conceive, that in situations precisely similar to those which imme diately precede these events, the ray should be withheld, or the cloud should remain suspended in the atmosphere. The diffused splendour, and the fining moisture, are universally allowed to be in such situations invariably and inevita bly the results.
The doctrine of necessity extends to the mind what is thus obvious and uncontra dieted with respect to matter. It insists on the absolute and uncontrollable influ ence of motives upon the human will and conduct. It asserts, that the determina tions and actions of every individual flow, with unfailing precision and resistless operation, from the circumstances, mo tives, or states of mind by which they are preceded ; and that, in the whole series of his existence no specific feeling, thought, or act, could have been different from what it really was, these previous circumstances continuing the same. In the consideration of this subject, it is im portant not to confound necessity with compulsion, as the latter implies that the choice of the mind is effected viith re luctance, and in consequence of the exer cise of force upon inclination; whereas, whether the conclusion be formed with the full concurrence of the affections, or after a conflicting estimate, which leaves reason completely triumphant over incli nation: the mind is equally impelled by some controlling energy, and equally ne cessitated to the determination it adopts. It is of consequence also to the illustra tion of the subject, fully to comprehend the meaning of the term motive, which, it is to be remembered, comprehends both the bias of the mind and the end in view, and includes every thing that moves or influences the mind, and excites it to a choice or determination.
The grand argument in support of philosophical necessity is derived from the relation of cause and effect. If there be any one principle in which mankind, in all their reasonings upon natural ob jects, have more perfectly concurred than in any other, it is the maxim, that every effect requires a cause, or, in other words, that whatever begins to be, demands some antecedent circumstances tending to its production. Of the nature indeed of causation we are completely and pro. foundly ignorant. But from the invaria ble connexion between certain previous and certain subsequent circumstances in the world of matter, we infer the tenden cy of the former to accomplish the latter, and the indispensableness of the opera tion of the first to the existence of the phenomena immediately following, with the same confidence, as if a perfect ac quaintance with the arcane of nature had unfolded to us its necessity. The asso
ciation of ideas in our minds, arising from the unvarying connexion between certain preceding and subsequent appearances around us, becomes at length so fixed, that the observation of the first excites the undoubting expectation of the last ; and where any effects produced differ from what we have been used to observe, and consequently to expect, we instantly presume that the preceding circumstan ces must proportionally have varied, and without an alteration in these, an altera tion in the effect is pronounced impos sible. Now, though we predict the acts of moral agents with less certainty, and expect them with more hesitation than mingle in our calculations on natural phe nomena, this difference is attributable merely to our ignorance of the tempers, characters, and situations of those agents, to the difficulty, and frequently the im possibility, which we experience of ex ploring the labyrinth of the human heart, and nothing in the slightest degree to any doubt, that volitions will always be precisely determined by preceding states of mind, and that certain volitions will in evitably be productive of certain acts. As, with regard to natural objects, we are led to consider some things the cause of others, concluding them to possess over these others a necessary and causative operation from their invariable conjunc tion, so particular states of mind, being uniformly observed to be connected with particular determinations, are equally re garded as causes of which these determi nations are the effects. The generative and irresistible influence of the motive upon the determination is inferred with as much justness and conviction as that of a certain degree of heat on liquifaction, or of cold on congelation ; and a change of determination in the mind, while pre ceding circumstances continued the same, is considered equally impossible as that iron should swim, precisely in the same circumstances in which it previous. ly sunk; or heat congeal, exactly in the same circumstances in which it has been uniformly observed to liquify. Thus, in the world of mind, as well as matter, no change of event takes place without a correspondent alteration in preceding circumstances, leading to it And operating upon it. This principle lies at the foun dation of all clear reasoning and legiti mate conclusion. Its denial would sub vert all the forms and degrees of human knowledge. All fair inference, reason able expectation, and judicious effort, would completely cease. Ignorance and confusion, hesitation and despair, would supersede an wise arrangement, lively hope, and heroic enterprize ; and the noble fabric of the universe, abounding in evidences of the most wise and kind design, might have started into being without any intelligent cause or pm-ced ing operation. But a position thus leading to consequences the most monstrous and absurd must be totally groundless.