When it is asserted, or implied, that Nature, or the laws of Nature, should be conformed to, is the Nature which is meant Nature in the first sense of the term, meaning all which is - the powers and properties of all things? But in this signification there is no need of a recommendation to act according to nature, since it is what nobody can possibly help doing, and equally whether he acts well or ill. There is no mode of acting which is not conformable to Nature in this sense of the term, and all modes of acting are so in exactly the same degree. Every action is the exertion of some natural power, and its effects of all sorts are so many phenomena of nature, produced by the powers and properties of some of the objects of nature, in exact obedience to some law or laws of nature. When I voluntarily use my organs to take in food, the act, and its consequences, take place according to laws of nature: if instead of food I swallow poison, the case is exactly the same. To bid people conform to the laws of nature when they have no power but what the laws of nature give them - when it is a physical impossibility for them to do the smallest thing otherwise than through some law of nature, is an absurdity. The thing they need to be told is what particular law of nature they should make use of in a particular case. When, for example, a person is crossing a river by a narrow bridge to which there is no parapet, he will do well to regulate his proceedings by the laws of equilibrium in moving bodies, instead of conforming only to the law of gravitation and falling into the river.
Yet, idle as it is to exhort people to do what they cannot avoid doing, and absurd as it is to prescribe as a rule of right conduct what agrees exactly as well with wrong, nevertheless a rational rule of conduct may be constructed out of the relation which it ought to bear to the laws of nature in this widest acceptation of the term. Man necessarily obeys the laws of nature, or in other words the properties of things; but he does not necessarily guide himself by them. Though all conduct is in conformity to laws of nature, all conduct is not grounded on knowledge of them and intelligently directed to the attainment of purposes by means of them. Though we cannot emancipate ourselves from the laws of nature as a whole, we can escape from any particular law of nature, if we are able to withdraw ourselves from the circumstances in which it acts. Though we can do nothing except through laws of nature, we can use one law to counteract another. According to Bacon's maxim, we can obey nature in such a manner as to command it. Every alteration of circumstances alters more or less the laws of nature under which we act; and by every choice which we make either of ends or of means we place ourselves to a greater or less extent under one set of laws of nature instead of another. If therefore, the useless precept to follow nature were changed into a precept to study nature; to know and take heed of the properties of the things we have to deal with, so far as these properties are capable of forwarding or obstructing any given purpose; we should have arrived at the first principle of all intelligent action, or rather at the definition of intelligent action itself. And a confused notion of this true principle is, I doubt not, in the minds of many of those who set up the unmeaning doctrine which superficially resembles it. They perceive that the essential difference between wise and foolish conduct consists in attending, or not attending, to the particular laws of nature on which some important result depends. And they think that a person who attends to a law of nature in order to shape his conduct by it may be said to obey it, while a person who practically disregards it, and acts as if no such law existed, may be said to disobey it; the circumstance being overlooked, that what is thus called disobedience to a law of nature is obedience to some other, or perhaps to the very law itself. For example, a person who goes into a powder magazine either not knowing, or carelessly omitting to think of, the explosive force of gunpowder, is likely to do some act which will cause him to be blown to atoms in obedience to the very law which he has disregarded.
But, however much of its authority the "Naturam sequi" doctrine may owe to its being confounded with the rational precept "Naturum observare," its favourers and promoters unquestionably intend much more by it than that precept. To acquire knowledge of the properties of things, and make use of the knowledge for guidance, is a rule of prudence, for the adaptation of means to ends; for giving effect to our wishes and intentions, whatever they may be. But the maxim of obedience to Nature, or conformity to Nature, is held up not as a simply prudential but as an ethical maxim; and by those who talk of jus naturae even as a law, fit to be administered by tribunals and enforced by sanctions. Right action must mean something more and other than merely intelligent action; yet no precept beyond this last can be connected with the word "nature" in the wider and more philosophical of its acceptations. We must try it, therefore, in the other sense, that in which Nature stands distinguished from Art, and denotes, not the whole course of the phenomena which come under our observation, but only their spontaneous course.