PLATO (429-347 BCE)

  

“Human heads are both large and quite small,

It’s not thanks to what’s small that you’re tall.

If you think that your wig

Makes you bigger than big,

Then you're wrong, and your theory must fall.”

Note 0: I made a small change to this limerick, following a judicious correction offered by Margaret Dancy, whose limericking powers exceed mine by a long shot.  Thank you, Margaret!

Note 1: In the Phaedo, Plato’s mouthpiece, Socrates, claims that as a young man he used to believe that causes were material things, that the cause of human growth is eating and drinking, and that the cause of X’s being taller than Y is X’s head (because X is taller “by a head”).  Now, he says, he no longer accepts this.  One of his reasons is that the human head is small, and nothing that is small can be the cause of anything big (or tall).  At bottom, Plato is articulating a theory of causation that was taken for granted by philosophers (and scientists) for almost two thousand years.  According to this theory, nothing can make something else have a certain property unless it has that property itself.  The favorite example of this was heat: only hot things can make other things hot (by transferring heat to them).  Importantly, nothing cold can make something hot, and nothing hot can make something cold.  (The first person to draw my attention to this important theory of causation was Russ Dancy, my former colleague at Florida State University.  When I was a mere babe of an assistant professor, he ran a fantastic seminar on Plato's Parmenides that I attended, and I was hooked on Plato forever.)

Note 2: Actually, looking back over old emails, I found a (meter-wise imperfect) limerick I wrote for Russ and Margaret Dancy in 2009.  This blog gives me the opportunity to share it with you, as a token of gratitude to both of them:

There was an old man called Parmenides

Who was given to writing inanidies

He once said, "The One

Is not many, my son,"

Which gave Plato no end of anxiedies.

Note 3: Plato's Parmenides features the character Socrates.  But this time Socrates gets his comeuppance.  After Socrates has sketched out the Theory of Forms for which Plato is famous, Parmenides outlines five main criticisms that, to all appearances, doom the theory.  But then Parmenides changes tack and claims that there is a way to rescue the theory from the criticisms (well, maybe not from the fifth one, commonly known as The Greatest Difficulty), and proceeds to run through a series of roughly 180 arguments, divided into eight (or nine) sections, about the form of unity: The One.  The start of the first argument is: "If The One is (alternative translation: if it is one), The One would not be many, would it?"  This seems kind of nutty, but it all makes sense in the end.  It took me a couple of years to figure it out.  For more on this, see my contribution to the Stanford Encyclopedia of Philosophy on the Parmenides: http://plato.stanford.edu/entries/plato-parmenides/.  Masochists among you might also try looking at my Plato's Forms in Transition: A Reading of the Parmenides (Cambridge University Press, 2007).  None of this would have been possible without the kind of careful interpretive work to be found in Russ Dancy's Plato's Introduction of Forms (Cambridge University Press, 2004).