Jamesian Philosophy Refreshed

The Nobel Prize winning economist Kenneth Arrow died recently (February 21). Let us give his work some thought on his way out of this world. Arrow was best known for the "Arrow Impossibility Theorem," a powerful and very influential argument that given certain assumptions and five (quite reasonable sounding) goals, there is no actual or possible system of voting that will work every time -- that will avoid violating one or more of those goals -- because the conditions themselves are incompatible. Arrow accomplished this result, one regarded every since as foundational to social choice theory and welfare economics, in his Ph.D dissertation in 1950, when he was 31. It might have been tempting to spend the rest of his scholarly career defending and expanding on the terrain of that theorem. But he left that work for others, and many others have stepped in, including Amartya Sen. Arrow moved on, and among much else helped Gerard Debreu develop a rigorous proof of the exist...

How can we use statistics to get at causal impact? Of course, correlation does not imply causation. Remember my lesson from a Dilbert's comic last week. But still, there are inferences to be drawn somehow. It may be a fact that MacDonald's just spent a lot of money on an ad campaign involving firecrackers and tapdancing penguins. It may be, also, that they sold a million hamburgers worldwide yesterday. It does not follow that they sold the million hamburgers because of that ad campaign. What MacDonald's clearly wants is some idea of how many hamburgers they would have sold if they had had some other ad campaign in place, possibly some less expensive campaign. Something involving their familiar clown and his sidekicks. Here's a social sciency thing about "Bayesian structural time-series models" that aims at getting at the problem. It's actually based on the experiences of Google, paid clicks versus free clicks, etc. -- I just prefer the MacDonald...

Fascinating stuff. Most social science studies show that opinions on social/political matters have a lot of inertia behind them. Adults don't change their mind quickly and, when a mind does change, it is liable to snap back into the earlier position. But there was one study not long ago that seemed to show that gay marriage is an exception. Now, that study turns out to be a fraud. There's a great story on all this in NEW YORK .