Conformity to nature has no connection whatever with right and wrong. The idea can never be fitly introduced into ethical discussions at all, except, occasionally and partially, into the question of degrees of culpability. To illustrate this point, let us consider the phrase by which the greatest intensity of condemnatory feeling is conveyed in connection with the idea of nature - the word "unnatural." That a thing is unnatural, in any precise meaning which can be attached to the word, is no argument for its being blamable; since the most criminal actions are to a being like man not more unnatural than most of the virtues. The acquisition of virtue has in all ages been accounted a work of labour and difficulty, while the descensus Averni, on the contrary, is of proverbial facility; and it assuredly requires in most persons a greater conquest over a greater number of natural inclinations to become eminently virtuous than transcendently vicious. But if an action, or an inclination, has been decided on other grounds to be blamable, it may be a circumstance in aggravation that it is unnatural - that is, repugnant to some strong feeling usually found in human beings; since the bad propensity, whatever it be, has afforded evidence of being both strong and deeply rooted, by having overcome that repugnance. This presumption, of course, fails if the individual never had the repugnance; and the argument, therefore, is not fit to be urged unless the feeling which is violated by the act is not only justifiable and reasonable, but is one which it is blamable to be without.
The corresponding plea in extenuation of a culpable act because it was natural, or because it was prompted by a natural feeling, never, I think, ought to be admitted. There is hardly a bad action ever perpetrated which is not perfectly natural, and the motives to which are not perfectly natural feelings. In the eye of reason, therefore, this is no excuse, but it is quite "natural" that it should be so in the eyes of the multitude; because the meaning of the expression is, that they have a fellow feeling with the offender. When they say that something which they cannot help admitting to be blamable is nevertheless natural, they mean that they can imagine the possibility of their being themselves tempted to commit it. Most people have a considerable amount of indulgence towards all acts of which they feel a possible source within themselves, reserving their rigour for those which, though perhaps really less bad, they cannot in any way understand how it is possible to commit. If an action convinces them (which it often does on very inadequate grounds) that the person who does it must be a being totally unlike themselves, they are seldom particular in examining the precise degree of blame due to it, or even if blame is properly due to it at all. They measure the degree of guilt by the strength of their antipathy; and hence differences of opinion, and even differences of taste, have been objects of as intense moral abhorrence as the most atrocious crimes.
It will be useful to sum up in a few words the leading conclusions of this Essay.
The word "nature" has two principal meanings: it either denotes the entire system of things, with the aggregates of all their properties, or it denotes things as they would be, apart from human intervention.
In the first of these senses, the doctrine that man ought to follow nature is unmeaning; since man has no power to do anything else than follow nature; all his actions are done through, and in obedience to, some one or many of nature's physical or mental laws.
In the other sense of the term, the doctrine that man ought to follow nature, or, in other words, ought to make the spontaneous course of things the model of his voluntary actions, is equally irrational and immoral.
Irrational, because all human action whatever consists in altering, and all useful action in improving, the spontaneous course of nature.
Immoral, because the course of natural phenomena being replete with everything which when committed by human beings is most worthy of abhorrence, any one who endeavoured in his actions to imitate the natural course of things would be universally seen and acknowledged to be the wickedest of men.
The scheme of Nature, regarded in its whole extent, cannot have had, for its sole or even principal object, the good of human or other sentient beings. What good it brings to them is mostly the result of their own exertions. Whatsoever, in nature, gives indication of beneficent design proves this beneficence to be armed only with limited power; and the duty of man is to cooperate with the beneficent powers, not by imitating, but by perpetually striving to amend, the course of nature - and bringing that part of it over which we can exercise control more nearly into conformity with a high standard of justice and goodness.
This irresistible conviction comes out in the writings of religious philosophers, in exact proportion to the general clearness of their understanding. It nowhere shines forth so distinctly as in Leibnitz's famous Théodicée, so strangely mistaken for a system of optimism, and, as such, satirised by Voltaire on grounds which do not even touch the author's argument. Leibnitz does not maintain that this world is the best of all imaginable but only of all possible, worlds; which, he argues, it cannot but be, inasmuch as God, who is absolute goodness, has chosen it and not another. In every page of the work he tacitly assumes an abstract possibility and impossibility, independent of the divine power; and , though his pious feelings make him continue to designate that power by the word "Omnipotence," he so explains that term as to make it mean power extending to all that is within the limits of that abstract possibility.