But it is not my business here to refute the doctrine of necessity, or to speak more properly, the doctrine of inactivity, (for so was it called by the ancients;) but to shew that freedom, or power, as such, supposes, nay necessarily requires, in order to its subsistence and exercise, established general laws. And this is as evident, as that goods cannot be obtained, nor pains be avoided by us, unless there is a fixed way of getting the one, and shunning the other, which may be foreseen and followed by us.a
The enquiry in which man is chiefly interested, is the extent of his dominion, power, or sphere of activity, that he may know how to regulate himself and his actions; not waste his time and powers in vain, impossible attempts, to gain or change what is absolutely independent of him, but employ himself in the right exercise of his powers,<19> about objects subjected to his will. Accordingly, ancient philosophers have commonly set out in their moral enquiries, by distinguishing and classing the τα εϕ ημινa and the τα ουκ εϕ ημιν, the objects put by nature in our power, and those that are not. We have an excellent catalogue of them in the beginning of Epictetus’s Enchiridion; and in the following enquiry, there will be occasion to take notice of the most important branches of our power, in the natural and in the moral world, that is, over external and sensible objects, or over moral and intellectual ones.
An account of the way in which the enquiry into human nature is to be carried on analogously to natural philosophy.
But before I proceed to enquire into any of the general laws relative to human nature, and their effects and final causes; it is necessary, in order to give a clear view of the manner in which it is proposed to carry on that enquiry, and of the strict analogy between natural and moral philosophy, to observe:
That as in natural philosophy, though it would be but building a fine visionary Theory or Fable, to draw out a system of consequences the most accurately connected from mere hypotheses, or upon supposition of the existence and operation of properties, and their laws, which experience does not shew to be really existent; yet the whole of true natural philosophy is not, for that reason, no more than a system of facts discovered by experiment and observation; but it is a mixture of experiments, with reasonings from experiments: so in the same manner, in moral philosophy, though it would be but to contrive a beautiful, elegant romance, to deduce the best coupled system of conclusions concerning human nature from imaginary suppositions, that have no foundation in nature; yet the whole of true moral philosophy, will not, for that reason, be no more than a collection of facts discovered by experience; but it likewise will<20> be a mixed science of observations, and reasonings from principles known by experience to take place in, or belong to human nature.
Hypotheses in either are only to be admitted as questions to be enquired into.
But we may proceed in both by analysis and synthesis.
In neither case are hypotheses to be any further admitted, than as questions, about the truth or reality of which it is worth while to enquire; but in both we may proceed in the double method of analysis and synthesis: by the former endeavouring to deduce from some certain select effects, the simple powers of nature, and their laws and proportions; from which, by the latter method, we may infer or resolve the nature of other effects.a In both cases equally, as soon as certain powers or laws of nature are inferred from experience, we may consider them, reason about them, compare them with other properties, powers and laws; and these powers being found to be real, whatever conclusions necessarily result from such comparisons or reasonings, must be true concerning them; and do therefore denote as certainly some qualities, properties, attendants or consequents of them, as if these had been immediately discovered by experiment, instead of being deduced by strict reasoning, and necessary inference from principles known to be really true by experience: Or if before any property or law was known to be real, perchance many conclusions had been inferred from the very nature or idea of it, compared with other ideas, by necessary consequence; the moment such laws and properties are found<21> out to be real, then all the conclusions from them, which were before but mere abstract, hypothetical theories, become real truths, applicable to nature itself, and consequently a key to its operations.
Illustration by examples in natural philosophy.
The thing will be sufficiently plain if we take an example. One may draw several conclusions concerning gravity from the nature of the thing, without knowing that it is an universal law of nature; but the moment it is known to be such, all these abstract conclusions concerning the necessary effects of it in certain circumstances, become instead of mere theories, real truths, that is, real parts of the law of gravity, as far as it extends: or though one had never considered gravity in abstract, or made any necessary deductions from its nature and idea, before it was known to be an universal law of bodies; yet after it is found by experience to be such, if any properties, effects or consequences can be drawn from the very consideration of gravity itself, compared with other properties; all such conclusions, the moment they are found out, may be placed to the account of nature, and deemed parts of the natural law of gravity. Thus if the laws of centripedal forces have been determined with regard to an ellipsis, parabola, hyperbola, &c. it immediately follows, that if bodies move in such or such a curve, such and such must be the laws of their centripedal forces; and vice versa, if the laws of the centripedal forces of bodies are found to be such and such, it immediately follows, that such and such must be the nature of the orbits described by bodies that have such and such centripedal forces.
It must be the same in moral philosophy.
In like manner in moral philosophy, whatever can be proved to belong to, result from; or contrary wise, to be repugnant to the very definition of intelligence, volition, affection, habit, or any moral power; and a supposed law of such power will become a part of moral philosophy, so soon as such power is known to exist: or vice versa, any effects<22> that can only result from such a law, being found by experience to take place, the law itself must be inferred; and so of course all belonging to that law will come into philosophy, as appertaining to it, and be a key to moral nature and its phenomena, as such. Now of this kind of reasonings in moral philosophy, many instances occur in the following enquiry, almost in every chapter, which for that reason above-mentioned, have the same relation to moral philosophy, that abstract mathematical truths have to natural philosophy, and make part of it in the same way as these do of the latter.
Conclusions concerning moral philosophy.
In fine, the only thing in enquiries into any part of nature, moral or corporeal, is not to admit any hypothesis as the real solution of appearances, till it is found really to take place in nature, either by immediate experiment, or by necessary reasonings from effects, that unavoidably lead to it as their sole cause, law, or principle. But all demonstrations which shew that certain moral ideas must have certain relations, that is, certain agreements and disagreements, are in the same way a key to moral nature, that demonstrations relative to the agreements and disagreements of sensible ideas, as gravity, elasticity, circles, triangles, &c.