Associate Professor, Department of Philosophy, Lewis & Clark College

Putnam's Peg Argument and Sober's Response

Added on by jay odenbaugh.

Hilary Putnam argues against reductionism on the basis of the "peg argument." Elliott Sober summarizes it as follows, 

Suppose a wooden board has two holes in it. One is circular and has a 1-inch diameter; the other is square and is 1 inch on a side. A cubical peg that is 15/16ths of an inch on each side will fit through the square hole, but not the circular one. What is the explanation? Putnam (1975) says that the explanation is provided by the macro-properties just cited of the peg and the holes. He denies that the micro-properties of molecules or atoms or particles in the peg and the piece of wood explain this fact. The micro- description is long and complicated and it brings in a welter of irrelevant detail. To explain why the peg goes through one hole but not the other, it does not matter what micro-properties the molecules have, as long as the peg and board have the macro-properties I mentioned. The macro-properties are explanatory; the micro-properties that realize those macro- properties are not. Hence, reductionism is false. (304) 

Sober's response goes as follows, 

Perhaps the micro-details do not interest Putnam, but they may interest others, and for perfectly legitimate reasons. Explanations come with different levels of detail. When someone tells you more than you want to hear, this does not mean that what is said fails to be an explanation. There is a difference between explaining too much and not explaining at all. (304-5)

Is this a reasonable response to the "peg argument"? Why or why not?