Plato’s Parmenides contains an argument against the so-called Platonic theory of forms known as the “Third Man Argument”.
Here’s how it goes:
- Bill Clinton, George W. Bush and Barack Obama are each “human”.
- We infer that there must be a Form called “Human-ness” by which these “humans” participate.
- Now these three men are alike because they are human. Moreover, these humans are like the Form of “Human-ness.” Consequently, we now have new set of things that are human: Human-ness, Bill Clinton, George W. Bush and Barack Obama.
- We now need a new Form of Human-ness to account for all these human things, including the original Form of “Human-ness”. Let’s call this new overarching Form “Super-Human-ness.”
- But now we have an entirely new set of things all alike by way of being human: Super-Human-ness, Human-ness, Bill Clinton, George W. Bush and Barack Obama. It doesn’t stop with this third “Super-Form.” We would have to keep on supplying “Super-Duper Form of Human-ness” and “Even-More-Super-Duper Form of Human-ness: it goes on and on forever. We have an infinite regress, which shows that the theory is absurd.
What does this all mean? The theory of forms assumes that predication is explained by participation and that arguments should not be circular. The Third Man Argument indicates a problem.
Here are some helpful articles on the Third Man Argument:
Cohen, S. M., “The Logic of the Third Man,” Philosophical Review 80 (1971) 448-475.
Geach, P. T., “The Third Man Again,” Philosophical Review 65 (1956) 72-82.
Owen, G.E.L., “The Place of the Timaeus in Plato’s Dialogues,” Classical Quarterly n.s. 3 (1953) 79-95; also in Studies in Plato’s Metaphysics, ed. by R. E. Allen (London: Routledge & Kegan Paul, 1965) 313-338.
Sellars, W., “Vlastos and the Third Man,” Philosophical Review 64 (1955) 405-437.
Strang, C., “Plato and the Third Man,” Proceedings of the Aristotelian Society, Suppl. vol. 37 (1963) 147-164; also in Plato: A Collection of Critical Essays, vol. 1, ed. by G. Vlastos (New York: Anchor, 1971) 184-200, and on reserve in OUGL.
Vlastos, G., “The Third Man Argument in the Parmenides,” Philosophical Review 63 (1954) 319-349; also in Studies in Plato’s Metaphysics, ed. by R. E. Allen (London: Routledge & Kegan Paul, 1965) 231-263.
Taylor Marshall is the Adjunct Instructor in Philosophy at the University of Dallas. 
geez, philosophy is sooooo confusing!
Don’t worry. We’ll make it less confusing when we cover it in class.
still foggy on this
Methinks, after reading about Plotinus and “The One”, that there cannot be a third man argument. If there is one divine being that is the simple explanation of everything then there is no infinite regress.
I’m not in your class but I love this blog
It makes Philosophy a lot less intimidating. Thanks!
Mr. Mondragon,
So are you inferring that the Hen or Monad of Plotinus is the Form of all? Remember, the Third Man Argument isn’t simply infinite regress, but that each particular form would regress infinitely based on the definition of “participation.”
Amal,
Thank you. Welcome the site!
Metaphysically,
Taylor Marshall
The “Third Man Argument” definitely makes much more sense after reading this.
Does this mean I get a 100 for my h.w. grade??
I remember my philosophy-major brother trying to explain the third man argument to me years ago… This provides a nice summary/review.
As you indicated an interest in hearing…
Upon asking a freshman philosophy major to provide an answer to this argument, I was told that which a form has in common with that which participates in it is nothing other than the form itself.
I am enjoying this class very much. Thank you for teaching!
So, if I am understanding this correctly, a “Form” is like a cookie mold, and what we see in the world is like the cookie. But, something must have made the mold – a “cookie mold mold” . And something must have made that mold – a “cookie mold mold mold.” Is that right? It’s a bit confusing since Form’s are suppose to be the perfect idea of substantive things. The Form of Perfect Square can’t have another form of Perfect Perfect square. I mean, you can’t have more perfect square than a perfect square