In the state of nature, therefore, sin is inconceivable; it can only exist in a state, where good and evil are pronounced on by common consent, and where everyone is bound to obey the State authority. Sin, then, is nothing else but disobedience, which is therefore punished by the right of the State only. Obedience, on the other hand, is set down as merit, inasmuch as a man is thought worthy of merit, if he takes delight in the advantages which a State provides. Again, in the state of nature, no one is by common consent master of anything, nor is there anything in nature, which can be said to belong to one man rather than another: all things are common to all. Hence, in the state of nature, we can conceive no wish to render to every man his own, or to deprive a man of that which belongs to him; in other words, there is nothing in the state of nature answering to justice and injustice. Such ideas are only possible in a social state, when it is decreed by common consent what belongs to one man and what to another. From all these considerations it is evident, that justice and injustice, sin and merit, are extrinsic ideas, and not attributes which display the nature of the mind. But I have said enough. PROP. XXXVIII. Whatsoever disposes the human body, so as to render it capable of being affected in an increased number of ways, or of affecting external bodies in an increased number of ways, is useful to man; and is so, in proportion as the body is thereby rendered more capable of being affected or affecting other bodies in an increased number of ways; contrariwise, whatsoever renders the body less capable in this respect is hurtful to man. Proof.--Whatsoever thus increases the capabilities of the body increases also the mind's capability of perception (II. xiv.); therefore, whatsoever thus disposes the body and thus renders it capable, is necessarily good or useful (IV. xxvi. xxvii.); and is so in proportion to the extent to which it can render the body capable; contrariwise (II. xiv., IV. xxvi. xxvii.), it is hurtful, if it renders the body in this respect less capable. Q.E.D. PROP. XXXIX. Whatsoever brings about the preservation of the proportion of motion and rest, which the parts of the human body mutually possess, is good; contrariwise, whatsoever causes a change in such proportion is bad.