The Beauty of the Reductio ad Absurdum

Reductio ad absurdum can be striking, indeed beautiful, in its simplicity. Taking a bad premise to its logical extreme can concisely illustrate just how bad the premise is. Here are my two favorite 'reductios'.

The first is in response to epistemological relativism in philosophy of science. The basic claim (i.e., the bad premise) is that truth and knowledge are socially determined; I believe what I do because of my contingent history of social, economic, and cultural experiences.

If this assertion is made 'in good faith', it eats itself. If its true, then by necessity, the speaker believes it only by virtue of his social history. On the other hand, if the speaker has non-social reasons to believe the assertion, then the assertion can't be true (at least not in its strongest form).

Clearly personal social histories play some role in what and why people believe what they do. Just as clearly, one's social history is not the sole determinant of one's beliefs. If it were, I'd be just as much a socialist, epistemological relativist as the middle-class suburbanites in the typical 'arts and science' department. But I'm not. Personal social histories play a role in the formation of belief systems, but they clearly do not determine them.

My second favorite (i.e., the second on my list of favorites, not my slightly-less-favorite) reductio applies to arguments for (raising the) minimum wage. Proponents of raising the minimum wage typically argue that it is necessary in order for poor folks to work their way out of poverty. From the official Democratic platform (p. 30, pdf here):
The dream of the middle class should belong to all Americans willing to work for it. We still have work to do as long as millions of Americans work full-time, fulfill their responsibilities, and continue to live in poverty. We will offer these Americans a ladder to the middle class. That means raising the minimum wage to $7.00,....
Why stop at $7.00? If raising the minimum wage to $7.00 will help people ascend to the middle class, won't raising it to $7.50 make the ascension quicker? How about $10.00? $20.00? $1000?

The natural, and correct, response to this reductio ad absurdum is to point out that paying someone, say, $1000 per hour when their labor is worth far less than this is ridiculous. But this same logic applies to any stipulated wage floor. If someone wants and is willing to work for $3.00 per hour, why stop them?

Granted, it wouldn't be easy to pay rent and buy food working for $3.00 an hour, especially if you have to house and feed more than just yourself, but it would be easier to do so at $3.00 an hour than it would at $0.00 an hour. Legislating a lower limit on what members of the labor pool can accept for their services prices the least experienced out of the job market (here's an old Cato article about it that quotes Walter Williams' excellent State Against Blacks [which I first heard about when I read this article about the minimum wage at Mises.org]). It becomes quickly clear that the issue is less that of raising the minimum wage than it is that of having a minimum wage at all.

Of course, the reductio ad absurdum isn't the only, or even the most, useful logical tool. The cases against relativism and the minimum wage can be developed a good ways beyond the simple arguments made above. But the reductio's beauty is in its ability to allow a lousy premise to imply its own demise. It's like logical tai-chi.

1 comment:

Joshua said...

I agree that reductio arguments are really satisfying, but I'm not sure I completely agree that this one works against the "living wage" crowd. More precisely, it works against the average "living wage" supporter, but not against the intellectuals behind the proposal.

Most of the intellectual forces behind "living wage" laws are also committed to inflationary economic policies. That is, inflation is not just a pesky side-effect of wealth redistribution for them, it's actually desireable as (a) economic stimulus (they believe) and (b) a mechanism for economic planning. Inflation puts/keeps economic policy - at least in part - in the hands of the government.

To people who have actually thought about minimum wage policy beyond "corporations are evil" or "feed children, not billionaires," I imagine that minimum wage policy is no different from normal wage raise negotiations that go on in corporations. These people think of the nation as a giant corporation which the government should be "running." Regular raises are part of the deal - especially given that their economic policies ensure that prices go up over time. Probably they would respond that the same market forces (in their understanding of "market" - which is to say, something that's nothing like a real market) that keep companies from raising wages ad libido also keep them from doing so. The only difference - they say - is that they're centralizing planning, which they believe is more efficient and/or humanitarian than leaving it up to the "whims of the market" or what have you.

Of course, you and I know that this is folly. Government mucking with wages has the same effect as government mucking with anything: it might keep income disparities narrower, but it ultimately also (a) keeps everyone (crucially especially those it's trying to help) poorer and (b) destroys the very information that makes cogent economic planning possible in the first place (by setting wages rather than finding out what they actually are).

As for the reductio, though, that really only works against the people in the marches carrying the signs. The people who write books about this would have a response for you.

(As a sidenote - I'm planning to use the "living wage" in my lesson on propaganda for Language and Politics discussion section next week since I very much think that it is a modern example of Soviet-style sloganeering. I'll let you know how it goes.)