from their mechanical causes; so that a person cannot do indifferently either of the actions A, and its contrary a, while the previous circumstances are the same; but is under an absolute necessity of doing one of them, and that only. Agreeably to this I suppose, that by free-will is meant a power of doing either the action A, or its contrary a; while the previous circumstances remain the same.
If by free-will be meant a power of beginning motion, this will come to the same thing; since, according to the opinion of mechanism, as here explained, man has no such power; but every action, or bodily motion, arises from previous circumstances, or bodily motions, already existing in the brain, i.e. from vibrations, which are either the immediate effect of impressions then made, or the remote compound effect of former impressions, or both.
But if by free-will be meant any thing different from these two definitions of it, it may not perhaps be inconsistent with the mechanism of the mind here laid down. Thus, if free-will be defined the power of doing what a person desires or wills to do, of deliberating, suspending, choosing, &c. or of resisting the motives of sensuality, ambition, resentment, &c. Free-will, under certain limitations, is not only consistent with the doctrine of mechanism, but even flows from it; since it appears from the foregoing theory, that voluntary and semi-voluntary powers of calling up ideas, of exciting and restraining affections, and of performing and suspending actions, arise from the mechanism of our natures. This may be called free-will in the popular and practical sense, in contradistinction to that which is opposed to mechanism, and which may be called free-will in the philosophical sense.
I proceed now to the arguments which favour the opinion of mechanism.
First, then, it is evident to, and allowed by all, that the actions of mankind proceed, in many cases, from motives, i.e. from the influence which the pleasures and pains of sensation, imagination, ambition, self-interest, sympathy, theopathy, and the moral sense, have over them. And these motives seem to act like all other causes. When the motive is strong, the action is performed with vigour; when weak, feebly. When a contrary motive intervenes, it checks or over-rules, in proportion to its relative strength, as far as one can judge. So that where the motives are the same, the actions cannot be different; where the motives are different, the actions cannot be the same. And it is matter of common observation, that this is the case in fact, in the principal actions of life, and such where the motives are of a magnitude sufficient to be evident. It is reasonable therefore to interpret the obscure cases by the evident ones; and to infer, that there are in all instances motives of a proper kind and degree, which generate each action; though they are sometimes not seen through their
