“What becomes of human free will and agency? …it seems to me to involve one of the most admirable laws of conservation in nature—a law which presents a new proof of the wisdom of the Creator… It is necessary, then, to admit that free-will exercises itself within indefinite limits, if one wishes not to incur the reproach of denying it altogether. But, with all the follies which have passed through the head of man, with all the perverse inclinations which have desolated society, what would have become of our race during so many past ages? All these scourges have passed by, and neither man nor his faculties have undergone sensible alterations, as far at least as our observations can determine. This is because the same finger which has fixed limits to the sea, has set similar bounds to the passions of men—because the same voice has said to both, "Hitherto shalt thou come, and no farther!"”

Prologue
Anarchism : A History of Libertarian Ideas and Movements (1962)
Context: Proudhon goes on to suggest that the real laws by which society functions have nothing to do with authority; they are not imposed from above, but stem from the nature of society itself. He sees the free emergence of such laws as the goal of social endeavour. … Proudhon conceiving a natural law of balance operating within society, rejects authority as an enemy and not a friend of order, and throws back at the authoritarians the accusations leveled at anarchists; in the process he adopts the title he hopes to have cleared of obloquy.

De concordantia catholica (The Catholic Concordance) (1434)

Source: Law and Authority (1886), II
Context: Relatively speaking, law is a product of modern times. For ages and ages mankind lived without any written law, even that graved in symbols upon the entrance stones of a temple. During that period, human relations were simply regulated by customs, habits, and usages, made sacred by constant repetition, and acquired by each person in childhood, exactly as he learned how to obtain his food by hunting, cattle-rearing, or agriculture.
All human societies have passed through this primitive phase, and to this day a large proportion of mankind have no written law. Every tribe has its own manners and customs; customary law, as the jurists say. It has social habits, and that suffices to maintain cordial relations between the inhabitants of the village, the members of the tribe or community. Even amongst ourselves — the "civilized" nations — when we leave large towns, and go into the country, we see that there the mutual relations of the inhabitants are still regulated according to ancient and generally accepted customs, and not according to the written law of the legislators.

An Outline of the System of the Elements

In Quest of Democracy (1991)

2000s, Before In History (2004)

Source: Law and Authority (1886), II
Context: As man does not live in a solitary state, habits and feeling develop within him which are useful for the preservation of society and the propagation of the race. Without social feelings and usages life in common would have been absolutely impossible. It is not law which has established them; they are anterior to all law. Neither is it religion which has ordained them; they are anterior to all religions. They are found amongst all animals living in society. They are spontaneously developed by the new nature of things, like those habits in animals which men call instinct. They spring from a process of evolution, which is useful, and, indeed, necessary, to keep society together in the struggle it is forced to maintain for existence.

Source: Life, Sex, and Ideas: The Good Life Without God (2002), “Introduction” (p. xiii)

Book I, section 42; Translation by C.D. Yonge)
De Legibus (On the Laws)
Context: For there is but one essential justice which cements society, and one law which establishes this justice. This law is right reason, which is the true rule of all commandments and prohibitions. Whoever neglects this law, whether written or unwritten, is necessarily unjust and wicked.