The 17th forbids a man to be his own judge; the 18th, any interested person to be judge.
The 19th requires a resort to witnesses in a matter of fact, as between two contending parties.
This list of the laws of nature is only slightly varied in the other works. He enumerates none but those that concern the doctrine of Civil Society, passing-over things like Intemperance, that are also forbidden by the law of nature because destructive of particular men. All the laws are summed up in the one expression: Do not that to another, which thou wouldest not have done to thyself.
The laws of nature he regards as always binding in foro interno, to the extent of its being desired they should take place; but in foro externo, only when there is security. As binding in foro interno, they can be broken even by an act according with them, if the purpose of it was against them. They are immutable and eternal; 'injustice, ingratitude, &c., can never be made lawful,' for war cannot preserve life, nor peace destroy it. Their fulfilment is easy, as requiring only an unfeigned and constant endeavour.
Of these laws the science is true moral philosophy, i.e., the science of good and evil in the society of mankind. Good and evil vary much from man to man, and even in the same man; but while private appetite is the measure of good and evil in the condition of nature, all allow that peace is good, and that justice, gratitude, &c., as the way or means to peace, are also good, that is to say, moral virtues. The true moral philosophy, in regarding them as laws of nature, places their goodness in their being the means of peaceable, comfortable, and sociable living; not, as is commonly done, in a mediocrity of passions, 'as if not the cause, but the degree of daring, made fortitude.'
His last remark is, that these dictates of reason are improperly called laws, because 'law, properly, is the word of him that by right hath command over others.' But when considered not as mere conclusions or theorems concerning the means of conservation and defence, but as delivered in the word of God, that by right commands all, then they are properly called laws.
Chapter XVI., closing the whole first part of the Leviathan, is of Persons, Authors, and Things Personated. The definitions and distinctions contained in it add nothing of direct ethical importance to the foregoing, though needed for the discussion of 'Commonwealth,' to which he passes. The chief points under this second great head are taken into the summary.
The views of Hobbes can be only inadequately summarized.
I.—The Standard, to men living in society, is the Law of the State. This is Self-interest or individual Utility, masked as regard for Established Order; for, as he holds, under any kind of government there is more Security and Commodity of life than in the State of Nature. In the Natural Condition, Self-interest, of course, is the Standard; but not without responsibility to God, in case it is not sought, as far as other men will allow, by the practice of the dictates of Reason or laws of Nature.
II.—His Psychology of Ethics is to be studied in the detail. Whether in the natural or in the social state, the Moral Faculty, to correspond with the Standard, is the general power of Reason, comprehending the aims of the Individual or Society, and attending to the laws of Nature or the laws of the State, in the one case or in the other respectively.