In the section on justice Hume attacks the contract theory. Law, property, and the sacredness of contracts exist first in society, but not first in the state. The obligation to observe contracts is, indeed, made stronger by the civil law and civil authority, but not created by them. Law arises from convention, i. e., not from a formal contract, but a tacit agreement, a sense of common interest, and this agreement, in turn, proceeds from an original propensity to enter into social relations. The unsocial and lawless state of nature is a philosophical fiction which has never existed; men have always been social. They have all at least been born into the society of the family, and they know no-more terrible punishment than isolation. States are not created, however, by a voluntary act, but have their roots in history. The question at issue between Hobbes and Hume was thus adjusted at a later period by Kant: the state, it is true, has not historically arisen from a contract, yet it is allowable and useful to consider it under the aspect of a contract as a regulative idea.
Only once since David Hume, in Herbert Spencer, has the English nation produced a mind of like comprehensive power. Hume and Locke form the culminating points of English thought. They are national types, in that in them the two fundamental tendencies of English thinking, clearness of understanding and practical sense, were manifested in equal force. In Locke these worked together in harmonious co-operation. In Hume the friendly alliance is broken, the common labor ceases; each of the two demands its full rights; a painful breach opens up between science and life. Reason leads inevitably to doubt, to insight into its own weakness, while life demands conviction. The doubter cannot act, the agent cannot know. It is true that a substitute is found for defective knowledge in belief based upon instinct and custom; but this is a makeshift, not a solution of the problem, an acknowledgment of the evil, not a cure for it.