Let us only recapitulate, that the principles of action impel to action, and that the moral sense is given as an instructor to regulate our actions, to enforce one principle, to restrain another, and to prefer one to another when they are in opposition. Hence the laws of nature may be defined to be, Rules of our conduct founded on natural principles approved by the moral sense, and enforced by natural rewards and punishments.
In searching for these laws, it must be obvious from what is above said, that, by the moral sense, a difference is clearly established among our principles of action. Some are enforced by the consciousness of duty; some are left in a measure upon our own will. With respect to the former, we have no liberty, but ought to proceed to action; with respect to the latter, we may freely indulge every natural impulse, where the action is not disapproved by the moral sense. From this short sketch may be readily deduced all the laws of nature which govern human actions; though, in the present essay, the duty which a man owes to himself, where others are not concerned, is not comprehended.
Among the principles of action that compel us to do our duty, the principle of justice takes the lead. It consists of two branches, one to abstain from harming others, and one to perform our positive engagements. With respect to both, we have no liberty; but are bound to perform every act of justice as our indispensible duty. Veracity, fidelity, and gratitude, are principles of action which come under the same class. And with respect to the whole, it ought not to be overlooked, that the internal constitution of man is adjusted with admirable wisdom to his external circumstances as a social being. Were we allowed to prey upon one another like savage animals, there could be no society; and were there nothing in our nature that could bind us to instruct, to comfort, to benefit each other, society would be deprived of all its advantages, and man, in the midst of society, would be a solitary being. Benevolence is another principle of action, which, in many circumstances, by means of peculiar connections, becomes also an indispensible duty. Witness the connection of parent and child. We are obliged to provide for our children; it is strict duty, and the neglect of it causes remorse. In the case of other blood-relations, an only brother for example who depends entirely on us, we feel the same obligation, though in a weaker degree; and thus, through other connections, it diminisheth by successive gradations, till at last the sense of duty is lost in simple approbation, without any obligatory feeling. This is universally the course that nature holds. Her transitions are soft and gentle: she makes things approximate so nicely one to another, as to leave no gap or chasm. One other instance of a connection that produceth a sense of obligation, shall suffice. In the general case of procuring positive good to others or advancing happiness, without any connection save merely that of humanity, it is self-approbation and not strict obligation that is felt. But let us put the case of a person in distress. By this single circumstance, though it forms no intimate connection, the moral sense is influenced, and now it becomes a positive duty to exert our benevolence, by affording relief. The neglect of this duty is attended with remorse and self-condemnation; though not so pungent as where we betray our trust, or are the authors of positive mischief to others. Thus charity is by all men considered as a duty to which we are strictly bound.viii
With respect to principles of action that are not enforced by consciousness of duty, these we may restrain at pleasure, but may not always indulge at pleasure. For in various circumstances, the moral sense interposes, and forbids the gratification. Self-preservation is the strongest of all our principles of action, and the means are infinite which may be put in motion for that end. Yet here the moral sense frequently interposes, and gives no indulgence to the transgression of any positive duty, even for the preservation of life. Self-preservation, however it may alleviate, will not justify any wrong done to an innocent person: it will not justify treachery, nor infidelity. For once admitting it lawful to deprive a man of a hand or a foot in order to save my life; why not kill another to save my life? Both must be lawful or neither. The doctrine thus laid down in general, may be liable to misconstruction; and therefore it must be further explained. Self-preservation, it is certain, will not justify an immoral action. But then, in the circumstances of imminent danger, several actions become lawful, which are unlawful in ordinary circumstances. For example, to prevent dying of hunger, a man may take food at short-hand without consulting the proprietor. Seizing upon what belongs to another, is in ordinary circumstances an unlawful act: but in a case that can bear no delay, the act is lawful, because the approbation of the proprietor will be presumed. At any rate, it is his duty to relieve the distressed; and what he ought to give, may justly be forced from him when the delay of applying to a judge would be fatal. Another example, is the case of two men in a shipwreck, laying hold at the same instant of a plank which cannot support both. In this case it becomes lawful to struggle for the sole possession, though one must perish in the struggle: for each has an equal title to act for self-preservation; and if both cannot be preserved, mere force is the only method by which the controversy can be determined. If the moral sense have such authority over the principle of self-preservation, its authority must, if possible, be still more complete over the inferior principles that belong to the same class.
These are the outlines of the laws which govern our actions, comprehending what we may do, what we ought to do, and what we ought not to do. The two latter, as matter of duty, are the proper objects of law, natural and municipal. And no more seems requisite but to point out our duty, by informing us of what we ought to do, and what we ought not to do; seeing actions that come not under the character of duty, may be safely left to our own will. With regard then to what may be called our duty, the first and primary law is the law of restraint, by which we are prohibited to hurt others in their persons, goods, or whatever else is dear to them. This is a law which dictates to us what ought not to be done; and so sacred it is, as to yield to none of our principles of action, not even that of self-preservation. The second, which is a law dictating what we ought to do, binds us to the performance of our promises and covenants. Veracity occupies the next place. This law excludes not fable, nor any liberty of speech which tends to amusement. It excludes deceit only, and obliges us to adhere to truth where truth is expected from us. Fidelity is a fourth law, not less vigorous, though more confined, than veracity; for, as observed above, fidelity presupposes a peculiar connection betwixt two persons, to found a reliance on the one side, and on the other an obligation to fulfil what is justly expected. Gratitude comes next, limited, like fidelity, to particular objects, but more arbitrary as to what it requires of us. Gratitude, without doubt, is strictly our duty; but the measure of performance, and the kind, are left pretty much to our own choice. Benevolence occupies the last place; which, considered abstractly, is not a positive duty. But there are many connections of different sorts that make it a duty. I shall slightly mention a few. The connection of parent and child is one of the strongest, for it makes mutual benevolence an indispensible duty. Benevolence among other blood-relations becomes also a duty in particular circumstances, though here we seldom feel ourselves so firmly bound as in the former connection. Many are the connections, some intimate, some more slight, which come under the law of equity, and which bind us to the performance of certain acts of benevolence. I shall add but one connection more, namely, that which subsists betwixt us and a person in distress. Benevolence in that case becomes the duty of every one who can afford relief.
These several laws are admirably adjusted to our nature and circumstances, and tend in the most perfect manner to promote the ends of society. In the first place, as man is limited in power and capacity, the foregoing