Is man the measure of all things? And what does Protagoras mean by this exactly? Some have called him the father of relativism, but we will see in this article that Protagoras actually meant something very different by his famous statement. Read on to see how this relates to issues such as the Civil Rights movement of the 20th century and the debate over abortion.
The full quote is below:
“Of all things the measure is man, of the things that are, the existence of things that are and the non-existence of things that are not.“– Socrates quoting Protagoras in Plato’s Theaetetus, 152a
Is Protagoras really the father of relativism as people assume from this statement? Additional questions also arise, such as 1) is he talking about an individual or humanity as a whole, and 2) is he talking about sense perception only or value judgments as well?
Plato and Protagoras
In post 54, I discussed how much of the dialogue in Plato’s Theaetetus is taken up by Protagoras’ “man is the measure” statement. This dialogue gave us insight into how the Greeks at the time viewed such a statement.
To answer the first question I posited above, it seems that Plato and others viewed this statement as concerning the perception of the individual. Consider the following Socrates quote from Theaetetus:
“Is it not true that sometimes, when the same wind blows, one of us feels cold, and the other does not? or one feels slightly and the other exceedingly cold? . . . Then in that case, shall we say that the wind is in itself cold or not cold or shall we accept Protagoras’s saying that it is cold for him who feels cold and not for him who does not?”– Theaetetus 152b
It’s clear that Plato, as well as other Greeks such as Aristotle, interpreted Protagoras as meaning the individual.
The second question is a little trickier. It seems that at one place in the dialogue, Plato appears to be talking only about sense perception as in the preceding comment, but in another place, he applies Protagoras’ famous statement to values:
“Well then, Protagoras, what shall we do about the [‘man is the measure’] doctrine? Shall we say that the opinions which men have are always true, or sometimes true and sometimes false? For the result of either statement is that their opinions are not always true, but may be either true or false. Just think, Theodorus, would any follower of Protagoras, or you yourself, care to contend that no person thinks that another is ignorant and has false opinions? . . . Do not myriads of men on each occasion oppose their opinions to yours, believing that your judgment and belief are false?”– Plato, Theaetetus, 170c-d
This quote from Plato’s dialogue, as well as interpretations of this statement by Aristotle and Sextus Empericus, all seem to indicate that Protagoras was pointing to more than sense perceptions. They interpret him as referencing opinions and moral judgments. I venture to say that this is most certainly true.
What explains the discrepancy with Plato’s sense perception interpretation above? Plato simply used the sense perception argument earlier in the dialogue as a strawman argument to prove a philosophical point he was trying to make.
A Changing World
This is the point where many philosophers venture further into the abstract. They like to evaluate such statements as that of Protagoras in isolation from its historical context. It is part of the purpose of my blog to set many of these discussions of various philosophies in the context of the historical times in which we find them.
What we sorely lack today in academia is cross-pollination between disciplines. Academicians have become overly specialized to the point of being unable to connect the dots. If one asks such a person a question just outside of his field, he or she will retort that that is not their specialty. But it never seems to dawn on them to collaborate with the person in the other discipline so that they could not only learn more, but also connect the dots in order to develop a fuller picture of reality. If philosophers would collaborate with historians more, for example, then they just might understand their philosophy better, and vice versa.
This is where, I think, Copleston hits the mark and roots the potentially abstract statement in the solid ground of practicality. He points out that, unlike the Presocratics, the Sophists were reflecting more on the “phenomenon of culture,” largely due to their ever-increasing contact and interaction with foreign cultures.2 Gone were the Presocratic days of philosophy practiced in isolated, idyllic settings. The local cultures were advancing and getting more complex, and as various cultures came in contact with one another, this naturally prompted questions to arise in the thinkers of the day.
Copleston states that the Greeks were coming in contact with more advanced cultures like the Babylonians and Egyptians as well as less advanced cultures like the Thracians, who were the rednecks of their day. Copleston states the following:
“This being so, it was but natural that a highly intelligent people like the Greeks should begin to ask themselves questions; e.g., Are the various national and local ways of religious life, religious and ethical codes, merely conventions or not? Was Hellenic culture, as contrasted with non-Hellenic or barbarian cultures, a matter of (nomos/law), man-made and mutable…or did it rest on Nature, existing (phusei/nature)? Was it a sacred ordinance, having divine sanction, or could it be changed, modified, adapted, developed?“3 (italics mine)
The last sentence above is key, I think, in understanding Protagoras’ phrase. In modern language, we can think of this in terms of the seeming conflict between natural law and man-made law – phusis versus nomos.
Nomos Versus Phusis
The Greek philosophers noted that different cultures had laws and customs that were different from their own. At the same time, these laws and customs weren’t so different as to share no commonality; they shared many similarities. As you can imagine, this was fertile ground for deep reflection among Greek philosophers.
The main question at the time related to what orders society – is it a function of man-made law, nomos, or naturally-derived precepts, physis? Does the foundation for a well-ordered society come from man or nature? This was no small matter for discussion and contemplation and became the subject of vigorous debate throughout the fifth and fourth centuries B.C.4 This ethical debate in Western philosophy over natural law versus man-made law has continued in one form or another up to the present day. And we have none other than the Greek Sophists to thank for bringing this debate to light.
Natural law is defined by G.K. Chesterton as follows:
“…right reason in things which man with his unaided reason can see to be right….”5
Few of us, except maybe attorneys, can quote a statute that prohibits driving while inebriated. But if you would take a poll on whether this is a right or wrong action, I imagine you would get a near-unanimous, if not unanimous, response that drunk driving is morally wrong. The average sane person reasons that driving while impaired is wrong because the impaired individual is a hazard to life and property. One could say in this case that statutory law simply codifies consequences for an action that human beings instinctively know to be wrong. I imagine that there is no developed nation that does not have such a law to reflect what people know to be wrong. This is an example of where statutory law is in accordance with natural law.
Many scholars trace the origin of the concept of natural law to Aristotle, but his teacher Plato, and Plato’s teacher Socrates, also advocated for some form of natural rights.6 Having said that, it was Aristotle who developed the idea more fully and thus is considered the father of natural law. After Aristotle, the idea of natural law enjoyed a long, rich history of development in the West.
The Romans developed this concept further after Aristotle started honing it. Cicero (106 – 43 B.C.), statesman, lawyer, and skeptic, stated the following:
“True law is right reason in agreement with nature; it is of universal application, unchanging and eternal; it summons to duty by its commands, and averts from wrongdoing by its prohibitions.”– Cicero, De Re Publica, “De Legibus”, Book III, Section 22
Some scholars feel that Cicero’s discussion of natural law may have influenced St. Paul who, under inspiration, wrote:
“When Gentiles who have not the law do by nature what the law requires, they are a law to themselves, even though they do not have the law. They show that what the law requires is written on their hearts, while their conscience also bears witness and their conflicting thoughts accuse or perhaps excuse them.”– St. Paul, Epistle to the Romans, 2:14-15
St. Thomas Aquinas used St. Paul’s writings to develop his theory of natural law, stating that a human law is not valid unless it to conforms to natural law. Natural law theory, which formed the basis of jurisprudence in the West, came under scrutiny in the 19th century, which then began its precipitous decline.
Nevertheless, natural law theory remains alive and well, silently percolating just under the surface of Western jurisprudence. Before becoming a Supreme Court Justice, Clarence Thomas, according to his own declarations in speeches and so forth, had advocated for natural law theory. But during Senate hearings for his nomination, he seemed to do an about-face on the matter. There are many conservative and especially Catholic jurists who believe in natural law, but since natural law is so despised, they cannot publicly inject these beliefs into modern jurisprudence without repudiation and even derision. So, the question to ask is why is natural law so despised in modern times?
Natural Law and the Founding of the United States
Up until recent times, natural law was recognized as the basis of common law. Even the English philosopher John Locke (1632-1704), who was no orthodox Christian to say the least, stated:
“The state of Nature has a law of Nature to govern it, which obliges every one, and reason, which is that law, teaches all mankind who will but consult it, that being all equal and independent, no one ought to harm another in his life, health, liberty, or possessions; for men being all the workmanship of one omnipotent and infinitely wise Maker; sent into the world by His order and about His business….” (italics mine)– John Locke, from his Second Treatise on Civil Government, published in 1689
He went as far as saying that the people are justified in overthrowing the State if the State goes against natural law and fails to safeguard the “life, liberty, and property” of its citizens.7
Locke was the political philosopher who influenced the founding fathers of the United States the most. Thomas Jefferson picked up on Locke’s ideas, changed the language slightly, and penned the Declaration of Independence.
“…and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature’s God entitle them…. We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.” (italics mine)– Thomas Jefferson, Preamble to the Declaration of Independence
It is interesting to me that we have cast aside natural law, the bedrock upon which the United States was founded. This is one of the reasons the United States is morally and philosophically adrift. If you destroy the foundation, the edifice will crumble.
Positive law encompasses statutory law enacted by legislatures and common law derived from court precedent and social customs. But haven’t statutory and common law been part of Western tradition for hundreds of years? Why now suddenly call it positive law? The answer lies in the relationship of man-made law to common law.
Starting in the 19th century, natural law started to come under intense scrutiny, culminating in its eventual demise in Western jurisprudence in the 20th century. The roots of this go back to the political philosophers Hobbes and Hume, and came to full flowering with Jeremy Bentham (1748–1832), an English philosopher, jurist, and the father of modern utilitarianism.8 Bentham is famous for his “happiness principle,” which states:
“The greatest happiness of the greatest number is the foundation of morals and legislation.”9
This principle is just as concise as it is ambiguous. According to Bentham, there is no longer a transcendent moral foundation for human morals and societal legislation. The foundation for these concepts is subjective rather than objective. They lie within and go no further than the “happiness” of the human person. According to Bentham, happiness is obtained simply by experiencing pleasure and avoiding pain. The problem with this paradigm is that it takes the meaning out of life and reduces human existence to the level of an irrational animal.
John Austin (1790-1859) took Bentham’s amorphous blob of philosophical clay and formed it into what would become legal positivism. According to Austin, the law depended upon social facts and not its merits:
“The existence of law is one thing; its merit and demerit another. Whether it be or be not is one enquiry; whether it be or be not conformable to an assumed standard, is a different enquiry.”10
Just as Darwin’s theory of evolution divorced scientific theory from any consideration of divine causation, so Austin’s legal positivism divorced legal theory from natural law and divine principles – it is noteworthy that both theories developed at about the same time. Legal positivism effectively decoupled man-made law from natural law, setting it adrift in our modern world.
Legal positivism is based on nothing more than laws as they are produced and exist in society by legislatures and courts. One could say that it takes a very utilitarian approach to jurisprudence. The authority of the law rests simply on the governmental structures that people recognize as authoritative. There is no higher authority.
In summary, man-made law, when separated from natural law, becomes legal positivism. Positive law theory is very complex. My aim is to introduce the concept, but it is beyond the scope of this article to go into great depth on the topic. To put it another way, legal positivism does not depend upon divine commandments, revelation, human reason, or even human rights.11 Under the natural law system, man-made laws derive from and rest upon natural law. As such, they can be based on “God, nature, or reason.”12
Positive law arose in opposition to natural law just as Darwinism arose in opposition to the doctrine of creation. This is not surprising because with the separation of faith and reason with the Enlightenment – the theme of this blog – it would only be a matter of time before the natural would be separated from the supernatural in disciplines such as law and science.
Dr. Martin Luther King, Jr. and Natural Law Theory
Most people would be surprised to know that natural law theory formed the foundation of the Civil Rights movement in the 20th century and was invoked as such by none other than Dr. Martin Luther King, Jr.
King firmly rooted the American Civil Rights movement in St. Augustine’s natural law theory.13 The following statement captures this perfectly:
“A just law is a man-made code that squares with the moral law or the law of God. An unjust law is a code that is out of harmony with the moral law.”– Dr. Martin Luther King, Jr.
He also cited Aquinas, Martin Buber, and Socrates, among other authorities, to reinforce his arguments that the law was not simply a convention of society determined by the majority, as is the case with legal positivism.14 He sought to prove that “segregation is not only politically, economically, and sociologically unsound, it is morally wrong and sinful.”
And this makes perfect sense, for if man was the only source of law, then one could justify anything including slavery. And the U.S. Supreme Court did exactly that in their infamous Dred Scott decision in 1867. When man separates himself from the divine order, really anything can be justified by law.
Abortion and Positive Law Theory
On January 22, 1973, in a landmark 7-2 decision, the U.S. Supreme Court issued a decision in the case of Roe v. Wade that extended to women the right to choose whether or not to have an abortion. This murky legal ruling was loosely based on the Due Process Clause of the 14th Amendment to the U.S. Constitution. This clause was cited as the basis for a woman’s “right to privacy,” enabling her to seek and have an abortion if she so chooses.
This was just the beginning. The effects of positive law came to full maturity in the less high-profile but watershed Supreme Court decision in the case of Planned Parenthood v. Casey in 1992. In this decision, not only was Roe v. Wade affirmed, but the right to privacy was elevated to new heights – or depths, depending upon your perspective. In a stunning declaration, the Court proclaimed:
“At the heart of liberty is the right to define one’s own concept of existence, of meaning, of the universe, and of the mystery of human life.”
With this decision, any semblance of an objective standard, divine fiat, or natural law is gone. This is relativism in its fullest expression. This decision not only caused reverberations in legal philosophy but also in political, social, moral, and religious philosophy.15
Natural Law Versus Legal Positivism
The example with Martin Luther King, Jr., illustrates how natural law can influence man-made laws for the good. The acknowledging of natural law in this case led to freedom winning against oppression.
On the contrary, in the abortion example, the jettisoning of natural law has led to countless millions of deaths of innocent unborn babies and the eventual enthronement of man as God.
Natural law tells us that a woman’s body is made for conceiving, carrying, giving birth to, and caring for a child. Her breasts uniquely equip her to feed and nourish her baby from her own body. Her nurturing disposition enables her to meet the emotional needs of her child and to help her child connect to the human race through the intimate bond that the child shares with his mother.
All of this is turned upside-down when a woman hires a doctor to kill the baby inside of her – the one she is supposed to be giving life to. She and the doctor are violating natural law, not to mention revealed moral law. When they do this, they also kill the humanity inside of themselves, for a person cannot violate natural law without serious consequences to their own soul. We see this expressed in many ways, one of the most apparent being the intense anger that is so often associated with the pro-abortion movement. The law, whether natural or supernatural, is designed to set us free. People who are constantly angry are not free. The only hope for people who have committed such atrocities, and those who support them, is the forgiveness and redemption found in the Christian Church.
Man-made law guided by natural and divine law leads to life and freedom. Man-made law with no external guidance leads to slavery, oppression, and death. With the Planned Parenthood v. Casey decision, we reached the philosophical nadir of Western civilization; such a philosophical foundation will eventually lead to the complete collapse of society. We have to choose, as a society, whether we want to keep going down this road of destruction backed by legal positivism, or whether we want to return to the objective standards of the past and rebuild our crumbling civilization on natural law.
I hope you see by this discussion that philosophy matters. It is serious business with potential serious consequences given the wrong philosophy. The right philosophy can foster prosperity and happiness. For example, Marxism resulted in the deaths of hundreds of millions of people, not to mention an unfathomable amount of misery and oppression. On the other hand, teachings such as Aristotle’s on ethics and the soul helped form the bedrock of Western civilization with all of its benefits.
Because philosophy matters, how we answer the question of what Protagoras meant by his “man is the measure of all things” statement is paramount. It could make the difference between life or death and freedom or slavery in a particular society. Philosophical discussions today are often esoteric and thus impractical. It should be anything but that. It should be a matter of finding and applying the truth for the benefit of civilization and humanity. To put it another way, in what kind of culture do we want to live and raise children?
What did Protagoras mean? Is it akin to the Casey decision where the Supreme Court said that a person has the “right to define one’s own concept of existence, of meaning, of the universe, and of the mystery of human life” or is it something else?
Fortunately, Plato’s Protagoras dialogue has a key to interpreting this statement. In this portion of the dialogue, known as the “long speech” of Protagoras, Protagoras states what he considers essential for a civilization to grow and prosper. He does this in the context of a mythological story.
After people banded together to make cities, Zeus feared that they would be in danger of destroying themselves. He then sent Hermes to dispatch two gifts by which societies could succeed. Protagoras states the following:
“So Zeus, fearing that our race was in danger of utter destruction, sent Hermes to bring respect and right among men, to the end that there should be regulation of cities and friendly ties to draw them together.” (italics mine)– Plato, Protagoras, 322c
The two gifts are respect (aidos) and justice (dike). Like many Greek words, these terms are rich in meaning. Aidos can mean shame, modesty, and humility.16 Dike can mean “spirit of moral order.” For a society to function, it has to have a sense of right and wrong and a means to enforce laws based on that morality, and it needs citizens who are able to respect and obey a just government.
In the story, when Hermes asked Zeus if he should distribute these gifts to everyone or just a few, Zeus answered:
“To all. Let all have their share: for cities cannot be formed if only a few have a share of these as of other arts. And make thereto a law of my ordaining, that he who cannot partake of respect and right shall die the death as a public pest.”– Plato, Protagoras, 322d
Far from being a relativist, Protagoras is advocating for universal morality, where all people are sharing and participating in the same sense of justice, without which there would be anarchy.
Different Degrees of Wisdom
But on the other hand, in Theaetetus, he seems to be advocating for relativism:
“For I claim that whatever seems right and honorable to a state is really right and honorable to it, so long as it believes it to be so.”– Plato, Theaetetus, 167c
How can we reconcile these two claims? The answer seems to be found in the following quote:
“…in this way it is true both that some men are wiser than others and that no one thinks falsely.”– Plato, Theaetetus, 167d
The phrase “no one thinks falsely” is Protagoras’ way of stating that there is one universal truth that everyone participates in. At the same time, Protagoras says that not all people have the same grasp of this universal truth, for “some men are wiser than others.”
The State then must apply the common standards of morality to their particular situations, not inventing moral standards but simply applying them in the way that is best for society. This makes sense since Protagoras goes on to say that “wise men should substitute sound practices for unsound.”17 In other words, it is up to the wise legislator and judge to continually look for ways that the laws can best serve the citizenry.
Man Is the Measure of All Things
Let’s tie this all together. Remember I stated at the beginning that Protagoras and the Sophists were encountering a changing world inhabited by many very diverse cultures. But despite their marked differences with respect to their laws and customs, they shared some commonalities.
Far from denying universal truth, Protagoras was a staunch advocate for it. According to him, there are common moral tendencies that reside in all people, out of which societies make laws. But at the same time, societies apply those standards in ways that are most suited for their cultures, which explains the variance in laws and customs throughout the world. It is up to the wisest people of each society to recognize the best way to apply these standards to their particular cultures and when necessary, “substitute sound practices for unsound.”
We are really delineating the difference between knowledge and wisdom. Knowledge or truth is constant. Wisdom is the application of that truth. The Sophists were into practicality over and above abstract thought. It is up to the individual wise rulers of society to pool their collective wisdom in order to legislate prudently. It is up to the citizens to recognize that just laws are for their benefit and so must be obeyed.
In summary, Protagoras is teaching us, through his statement, that even though there is universal truth, it is up to us to perceive that truth and apply it to our particular situations as we take on the task of culture building, leaders and citizens alike.
Measuring Our Own Times
We – humans, society, legislators – are not the absolute standard of truth, despite what the Casey decision says. It is up to each of us, now more than ever, to learn the objective standards of morality contained within both natural law and divine law. We need to apply those principles to our particular circumstances and most importantly, be discerning about the laws of our governmental entities to determine which ones comport with objective truth and which ones do not. It is up to us to obey the just laws and to exercise civil disobedience vis-à-vis unjust laws.
And lastly, we need to pray for and work toward installing leaders in office who are truly humble enough to recognize a standard higher than their own and who are wise enough to apply them practically. This means getting the corrupt and stupid officials out of office…of which there is no shortage.
This is indeed a herculean task, and the only way we can accomplish this is if we become a virtuous people. It starts with each one of us individually. Only a virtuous citizenry can throw off wicked rulers. We need not remain pessimistic; this is possible if we citizens change our ways. And when we, by God’s grace, accomplish this, we will indeed be the measure of all things.
“It would appear that what Protagoras means is this: that Law in general is founded on certain ethical tendencies implanted in all men, but the individual varieties of Law, as found in particular States, are relative, the law of one State, without being “truer” than that of another State, being perhaps “sounder” in the sense of more useful or expedient.”18– Frederick Copleston, S.J.
Any thoughts on natural versus man-made law? Protagoras’ ultimate view of universal truth? Please leave them in the comment section below and don’t forget to subscribe. Thank you!
From Amazon: “Here, in this 1850 classic, a powerful refutation of Karl Marx’s Communist Manifesto, published two years earlier, Bastiat discusses: what is law?, why socialism constitutes legal plunder, the proper function of the law, the law and morality, “the vicious circle of socialism”, and the basis for stable government. French political libertarian and economist CLAUDE FRÉDÉRIC BASTIAT (1801-1850) was one of the most eloquent champions of the concept that property rights and individual freedoms flowed from natural law.”
- Copleston S.J., Frederick, A History of Philosophy, Book One, “Volume 1 Greece and Rome”, pp. 87-88, An Image Book, Doubleday, 1985
- Ibid., pp. 81-82
- Ibid., p. 82
- Hobbs, Angela. Physis and nomos, 1998, doi:10.4324/9780415249126-A087-1. Routledge Encyclopedia of Philosophy, Taylor and Francis
- Cooper, Kody, “What Happened to Natural Law in American Jurisprudence?” Federalist Society Review, Volume 22, December 13, 2021
- Shellens, Max Solomon (1959). “Aristotle on Natural Law”. Natural Law Forum. 4 (1): 72–100. doi: 10.1093/ajj/4.1.72
- Mineshema-Lowe, Dale, “Natural Law”, The First Amendment Encyclopedia, 2009
- Green, Leslie and Thomas Adams, “Legal Positivism”, The Stanford Encyclopedia of Philosophy (Winter 2019 Edition), Edward N. Zalta (ed.)
- Bentham, Jeremy. A Comment on the Commentaries and a Fragment on Government, edited by J.H. Burns and H.L.A. Hart. London: The Athlone Press. 1977. p. 393.
- Green, Leslie and Thomas Adams, “Legal Positivism”
- Himma, Kenneth Einar, “Legal Positivism”, Internet Encyclopedia of Philosophy.
- Kelsen, Hans (2007). General Theory of Law And State. The Lawbook Exchange, p. 392
- Allen, William, “Natural Law and American Civil Rights Movements”, Public Discourse, The Journal of the Witherspoon Institute, August 25, 2021
- Ascik, Thomas, “The Right to Create Your Own Universe?”, The Imaginative Conservative, August 17, 2018
- Bell, Robert E. (1991). Women of Classical Mythology: A Biographical Dictionary. ABC-CLIO. p. 6.
- Copleston S.J., Frederick, A History of Philosophy, Book One, “Volume, p. 89
- Ibid. pp. 89-90
Banner, Stuart, The Decline of Natural Law: How American Lawyers Once Used Natural Law and Why They Stopped, Oxford University Press (April 15, 2021)
Bastiat, Frederic, The Law, written in 1850, Creative Commons; Illustrated edition (May 24, 2013)
Brock, Rev. Stephen, The Light That Binds: A Study in Thomas Aquinas’s Metaphysics of Natural Law, Pickwick Publications (March 30, 2020)
Copleston S.J., Frederick, A History of Philosophy, Book One, “Volume 1 Greece and Rome”, An Image Book, Doubleday, 1985
Finnis, John, Natural Law and Natural Rights, Oxford University Press; 2nd edition (May 26, 2011)
Greaney, Michael; Brohawn, Dawn K., Greater Reset: Reclaiming Personal Sovereignty under Natural Law, TAN Books (March 15, 2022)
Jankunas, Gediminas T., Dictatorship of Relativism: Pope Benedict XVI’s Response, Alba House (April 4, 2011)
Jensen, Steven; Jensen, Steven J., Knowing the Natural Law: From Precepts and Inclinations to Deriving Oughts, The Catholic University of America Press (March 25, 2015)
McIntyre, Alasdair, After Virtue, University of Notre Dame Press; 3rd edition (March 6, 2007)
Plato, Theaetetus, Oxford World Classics, 1st Edition, Translated by John McDowell and Lesley Brown, April 1, 2014