Why was Slavery Wrong? Involuntariness or Treating Persons as Things?

“Involuntariness” is the usual answer.

Indeed, classical liberalism takes the most basic framing of a social question as: “consent or coercion?” In this view, democracy is characterized as government “with the consent of the governed” so slavery and non-democratic government were both condemned for the lack of consent.

This common condemnation of slavery on the basis of involuntariness has caused a large amount of intellectual history to just go “down the memory hole.” Those who routinely condemn involuntary slavery have either forgotten or never knew that from Antiquity down almost to the present there have always been those pro-slavery writers who: (1) presented a defense of slavery based on consent or contract, and (2) interpreted much of historical slavery as being based on implicit or explicit contracts.

My focus here is not on (2), the empirical question of whether or not any historical slavery could be interpreted as being voluntary, but (1), the fact of intellectual history that so many classical authorities defended slavery if based on consent.

Intellectual history of the voluntary slavery contract

The Old Testament of the Bible is a convenient starting point. The Old Testament law was that, after six years of service, any Hebrew slave was to be set free in the seventh year, the year of the Jubilee.

But if he says to you, “I will not go out from you,” because he loves you and your household, since he fares well with you, then you shall take an awl, and thrust it through his ear into the door, and he shall be your bondman for ever. [See Deut. 15:16-17; also Exodus 21:5-6.]

Much of Western jurisprudence was developed out of Roman law. In the Institutes of Justinian, Roman law provided three legal ways to become a slave.

Slaves either are born or become so. They are born so when their mother is a slave; they become so either by the law of nations, that is, by captivity, or by the civil law, as when a free person, above the age of twenty, suffers himself to be sold, that he may share the price given for him. [Institutes Lib. I, Tit. III, 4]

In addition to the third means of outright contractual slavery, the other two means were also seen as having aspects of contract. A person born of a slave mother and raised using the master’s food, clothing, and shelter was considered as being in a perpetual servitude contract to trade a lifetime of labor for those past and future provisions. In the natural rights tradition, Samuel Pufendorf (1632-94) explicitly gave that contractual interpretation.

Whereas, therefore, the Master afforded such Infant Nourishment, long before his Service could be of any Use to him; and whereas all the following Services of his Life could not much exceed the Value of his Maintenance, he is not to leave his Master’s Service without his Consent. But ’tis manifest, That since these Bondmen came into a State of Servitude not by any Fault of their own, there can be no Pretence that they should be otherwise dealt withal, than as if they were in the Condition of perpetual hired Servants. [Pufendorf 2003 (1673), 186-7]

Manumission was an early repayment or cancellation of that debt. And Thomas Hobbes, for example, clearly saw a “covenant” in this ancient practice of enslaving prisoners of war.

And this dominion is then acquired to the victor when the vanquished, to avoid the present stroke of death, covenants either in express words or by other sufficient signs of the will that, so long as his life and the liberty of his body is allowed him, the victor shall have the use thereof at his pleasure. … It is not, therefore, the victory that gives the right of dominion over the vanquished but his own covenant. [Hobbes 1958 (1651), Bk. II, chapter 20]

Thus all of the three legal means of becoming a slave in Roman law had explicit or implicit contractual interpretations.

In addition to giving a contractual interpretation to the slavery of a child born of a slave mother, Pufendorf noted that an explicit slavery contract was a lifetime version of the master-servant contract (employment contract in modern terms) where a servant could be hired or rented for a certain time and would receive wages.

But to such a Servant as voluntarily offers himself to perpetual Servitude, the Master is obliged to allow perpetual Maintenance, and all Necessaries for this Life; it being his Duty on the other hand to give his constant Labour in all Services whereto his Master shall command him, and whatsoever he shall gain thereby, he is to deliver to him. [Pufendorf 2003 (1673), 185]

John Locke’s Two Treatises of Government (1690) is a classic of liberal thought. Locke gave a ringing condemnation of a contract which gave the master the power of life or death over the slave.

For a Man, not having the Power of his own Life, cannot, by Compact or his own Consent, enslave himself to any one, nor put himself under the Absolute, Arbitrary Power of another, to take away his Life, when he pleases. [Second Treatise, §23]

Locke is ruling out a voluntary version of the old Roman slavery where the master could take the life of the slave with impunity. But once the contract was put on a more civilized footing, Locke saw no problem and nicely renamed it “drudgery.”

For, if once Compact enter between them, and make an agreement for a limited Power on the one side, and Obedience on the other, the State of War and Slavery ceases, as long as the Compact endures…. I confess, we find among the Jews, as well as other Nations, that Men did sell themselves; but, ’tis plain, this was only to Drudgery, not to Slavery. For, it is evident, the Person sold was not under an Absolute, Arbitrary, Despotical Power. [Second Treatise, §24]

Moreover, Locke agreed with Hobbes on the practice of enslaving the captives in a “Just War” as a quid pro quo exchange based on the on-going consent of the captive.

Indeed having, by his fault, forfeited his own Life, by some Act that deserves Death; he, to whom he has forfeited it, may (when he has him in his Power) delay to take it, and make use of him to his own Service, and he does him no injury by it. For, whenever he finds the hardship of his Slavery out-weigh the value of his Life, ’tis in his Power, by resisting the Will of his Master, to draw on himself the Death he desires. [Second Treatise, §23]

Locke seemed to have justified slavery in the Carolinas by interpreting the raids into Africa as just wars and the slaves as the captives [See Laslett1960, notes on §24, 325-26].

William Blackstone’s (1723-1780) codification of common law was quite important in the development of English and American jurisprudence. Like Locke, Blackstone takes a seemingly modern moral stand to rule out a slavery where “an absolute and unlimited power is given to the master over the life and fortune of the slave.” Such a slave would be free “the instant he lands in England.”

Yet, with regard to any right which the master may have lawfully acquired to the perpetual service of John or Thomas, this will remain exactly in the same state as before: for this is no more than the same state of subjection for life, which every apprentice submits to for the space of seven years, or sometimes for a longer term. [Blackstone 1959 (1765), 72, section on “Master and Servant”]

The Debates about American Slavery

An interesting case study in the selectiveness of liberal intellectual history is the treatment of the proslavery writers in the American debates. The proslavery position is usually presented as being based on illiberal racist or paternalistic arguments. Considerable attention is lavished on illiberal paternalistic writers such as George Fitzhugh [See, for example, Genovese 1971; Wish 1960; or Fitzhugh 1960] while consent-based contractual defenders of slavery are passed over in (embarrassed?) silence.

For example, Rev. Samuel Seabury [1969 (1861)] gave a sophisticated liberal-contractarian defense of ante-bellum slavery in the Hobbes-Pufendorf tradition of alienable natural rights theory.

From all which it appears that, wherever slavery exists as a settled condition or institution of society, the bond which unites master and servant is of a moral nature; founded in right, not in might; … . Let the origin of the relation have been what it may, yet when once it can plead such prescription of time as to have received a fixed and determinate character, it must be assumed to be founded in the consent of the parties, and to be, to all intents and purposes, a compact or covenant, of the same kind with that which lies at the foundation of all human society. [Seabury 1969 (1861), 144]

Seabury easily anticipated the retort to his classical tacit-contract argument.

“Contract!” methinks I hear them exclaim; “look at the poor fugitive from his master’s service! He bound by contract! A good joke, truly.” But ask these same men what binds them to society? Are they slaves to their rulers? O no! They are bound together by the COMPACT on which society is founded. Very good; but did you ever sign this compact? Did your fathers every sign it? “No; it is a tacit and implied contract.” [Seabury 1969, 153]

In American history, these consent-based defenses of slavery have gone down the memory hole. For instance, McKitrick (1963) collected essays of fifteen pro-slavery writers but does not include a single ante-bellum writer who argues to allow slavery on a contractual basis such as Seabury—not to mention the classical writers such as Grotius, Pufendorf, Locke, Blackstone and a host of others. Moreover it might be remembered that in the decade before the Civil War, six states had explicit laws “to permit a free Negro to become a slave voluntarily.” [Gray 1958, 527] For instance in Louisiana, legislation was passed in 1859 “which would enable free persons of color to voluntarily select masters and become slaves for life.” [Sterkx 1972, 149]

The philosophical tradition that voluntary contractual slavery should be allowed was brought up to the present in the work of Harvard’s libertarian philosopher Robert Nozick. He argued that a free libertarian society should validate that sort of a contract with a “dominant protective association” [Nozick 1974, 15] playing the role of the Hobbesian sovereign. And the same reasoning would re-validate the self-sale contract.

The comparable question about an individual is whether a free system will allow him to sell himself into slavery. I believe that it would. [Nozick 1974, 331]

Why is this intellectual history important?

When slavery was finally abolished, it was not even legal to own another person voluntarily. The whole system which allowed owning other people (involuntarily or voluntarily) was replaced with a system to voluntarily employ, hire, or rent other people. In the words of the late Nobel Prize-winning economist, Paul Samuelson:

Since slavery was abolished, human earning power is forbidden by law to be capitalized. A man is not even free to sell himself; he must rent himself at a wage. [Samuelson 1976, 52 (emphasis in original)]

If historical slavery was wrong because it was involuntary, then the current system of voluntarily renting other people would be on a different moral footing—but then so would a system of voluntary contractual ownership of other people. If, on the other hand, slavery was wrong—regardless of it being voluntary or involuntary—because it treated persons as things, then the whole current system of renting other people in the employment contract is called into question.

For more intellectual history and for the continuation of this line of argument, see my 1992 book which can now be downloaded from my website here.


Blackstone, William 1959 (1765). Ehrlich’s Blackstone. J. W. Ehrlich, (ed.), New York: Capricorn Books.

Ellerman, David 1992. Property & Contract in Economics: The Case for Economic Democracy. Cambridge MA: Blackwell. Downloadable from: www.ellerman.org

Fitzhugh, George 1960 (1857). Cannibals All! or, Slaves Without Masters. Cambridge: Harvard University Press.

Genovese, Eugene 1971. The World the Slaveholders Made. New York: Vintage Books.

Gray, Lewis Cecil 1958. History of Agriculture in the Southern United States to 1860. Gloucester: Peter Smith.

Hobbes, Thomas 1958 (1651). Leviathan. Indianapolis: Bobbs-Merrill.

Laslett, Peter 1960. Introduction with Notes. In John Locke: Two Treatises of Government. Peter Laslett (ed.), New York: New American Library.

Locke, John 1960 (1690). Two Treatises of Government. New York: New American Library.

McKitrick, Eric, (ed.) 1963. Slavery Defended: the views of the Old South. Englewood Cliffs NJ: Prentice-Hall.

Nozick, Robert 1974. Anarchy, State, and Utopia. New York: Basic Books.

Pufendorf, Samuel 2003 (1673). The Whole Duty of Man, According to the Law of Nature. Indianapolis: Liberty Fund.

Pufendorf, Samuel 1703. Of the Law of Nature and Nations. B. Kennet (trans.), Oxford.

Samuelson, Paul A. 1976. Economics. Tenth edition. New York: McGraw-Hill.

Seabury, Samuel 1969 (1861). American Slavery Justified by the Law of Nature. Miami: Mnemosyne Publishing Company.

Sterkx, H. E. 1972. The Free Negro in Ante-Bellum Louisiana. Cranbury, N.J.: Associated University Presses.

Wish, Harvey, (ed.) 1960. Ante-bellum. New York: Capricorn Books.