Philosophy 21, Fall, 2004 Reconstruction of an Argument for Protagorean Relativity
Protagoras of Abdera is famous for advocating a doctrine of relativity, according to which each individual person is a “measure” of truth and reality. One statement of the doctrine can be found in Plato’s Theaetetus: “Not that any one ever made another think truly, who previously thought falsely. For no one can think what is not, or think anything different from that which he feels; and this is always true” (167b). Aristotle tells us that “he said that man is the measure of all things, meaning simply that that which seems to each man also assuredly is” (Metaphysics, 1062b 13). The basis for this doctrine is found by Plato and Aristotle in the fact that people disagree about many things, such as whether an object is beautiful or whether a breeze is cold. Plato at least seems to have been willing to admit that the feeling of cold is relative. Even if it is, the relativity of some terms is not an adequate basis for a fully general claim about relativity. It may be, to use one of Aristotle’s examples, that an object appears to one person as a man, to another as a ship, and to yet another as a wall (Metaphysics, 1007b 20). Do we want to say that the object is both a man, a ship, and a wall? We can find an argument for the general thesis of relativity in Sextus Empiricus. “He asserts that all sense-impressions and opinions are true and that truth is a relative thing inasmuch as everything that has appeared to someone or has been opined by someone is at once real in relation to him” (Against the Logicians I. 61). Let us try to make this argument more exact, using the case of opinion. We will restrict ourselves to opinions about really existing objects. 1. For all x and persons y, if y has the opinion that x is O, then x’s being O is real for y. 2. For any x and person y, if x’s being O is real for y, then O is true of x for y. 3. So, for all x and persons y, if y has the opinion that x is O, then O is true of x for y. 4. For all x and persons y, if O is true of x for y, then O is true of x. 5. So, for all x and persons y, if y has the opinion that x is O, then O is true of x. The key premises in this argument are 2 and 4. We can take 2 to be a way of understanding the expression “true for.” Premise 4 makes the crucial claim that truth for any one person is the truth pure and simple. Most opponents of relativism, such as Aristotle, would concentrate their criticism on premise 4. They might be inclined to allow that there is a harmless notion of being true for a person, so long as it is understood merely as an expression of the fact that the content of the person’s opinion in some way is “real” in the mind of that person, as premise 2 puts it. What they object to is the view that “truth” taken in this way should be understood to be truth in an unqualified way. According to the opponents of relativism, “truth” understood in an unqualified way indicates a relation of “correspondence” between the “reality” in S’s mind of x’s being O and a reality that is independent of what is going on in S’s mind. A relativist could deny that there is any such thing as mind-independent reality, which would make a correspondence account of truth impossible. Protagoras himself seems not to have taken this line. Instead, he emphasized that individual human beings are the “measure” of reality. Modern relativists argue that any description we make of reality is the result of the way we have (in Protagorean terms) “measured” it. We cannot get outside ourselves to evaluate the success of our “measuring” of reality, and the only alternative is to hold that our own individual “measuring” is the standard of truth. The fact that all opinions must be called “true” does not mean that any opinion is just as good as any other. As presented by Plato, Protagoras allowed that the opinions of a “healthy” soul are better, though not “truer,” than the opinions of an “unhealthy” soul (Theaetetus 167b). Perhaps we should say that the healthy soul is better at “measuring” what is and what is not. http://hume.ucdavis.edu/mattey/phi021/ProgatgorasRelativism.pdf Moq_Discuss mailing list Listinfo, Unsubscribing etc. http://lists.moqtalk.org/listinfo.cgi/moq_discuss-moqtalk.org Archives: http://lists.moqtalk.org/pipermail/moq_discuss-moqtalk.org/ http://moq.org/md/archives.html
