Emanuel Derman

Dog’s Lives

Emanuel Derman
Aug 5, 2012 17:49 UTC

I am in Santa Fe, NM, about to spend a few weeks at the Santa Fe Institute where I hope to learn something about market microstructure and agent-based models.

Everyone in Santa Fe (i.e. the few people I’ve met thru work here in the past — I wrote a chapter of Models.Behaving.Badly here in 2009, using their excellent library) seems to think Santa Fe is paradise on earth, and maybe it is, though I prefer paradise on the seashore. I  have this atavistic urge to find a place that is easygoing but has access to culture, and yet lets you back off from the discontents and irritations of politics and corporations. People here seem to think this is it. But, I should add, people here seem to be close to retirement.

One of the points I tried to make in Models.Behaving.Badly was that models were analogies, comparing something you don’t understand to something you do, e.g. a nucleus to a liquid drop, or stock returns to smoke diffusion, whereas theories were (attempts to discover) absolute (rather than relative) descriptions of phenomena (e.g. Newton’s laws or relativity). I spent an evening with an accomplished physicist here, and was pleased to see that he agreed. When I was here last I read Maxwell’s papers from the 1860s; he called his final description of the electromagnetic field a theory, having first tried a bunch of metaphorical models to warm up his intuition and understanding.


En route here, Aaron Brown emailed to ask how I came up with the title My Life as a Quant, as background to an article he’s writing. This led me to the following recollection:

When my kids were really small, no more than three or four years old, I used to love to take them to entertainment that was simultaneously enjoyable for adults and children, eve if on different level. On TV you could find Sesame Street and The Muppet Show. For live performances, among others I had lucky strikes with Joseph and the Amazing Technicolor Dreamcoat at a theater on 2nd Ave, The Paper Bag Players at Symphony Space, a show of Randy Newman songs in the East Village. I remember my son becoming mesmerized by the latter.

The perils of pragmamorphism

Emanuel Derman
Sep 23, 2011 14:57 UTC

Having been a scientist, one of my major pet peeves is the naïve use of science. Let me give you several examples.

The influential biologist and evangelistic atheist Richard Dawkins wrote in the Los Angeles Times several years ago about what he called the scientific “vandalism” involved in hanging Saddam Hussein:

“Hussein’s mind would have been a unique resource for historical, political and psychological research, a resource that is now forever unavailable to scholars. … Psychologists, struggling to understand how an individual human being could be so evil … would give their eye teeth for such a rich research subject. Political scientists … have now lost key evidence forever.”

Dystopic finance

Emanuel Derman
Sep 8, 2011 11:54 UTC

For a couple of years now I’ve had a bad feeling about the field of finance. Though I often inveighed against the mechanical use of models, I didn’t damn the entire endeavor. I still don’t, but the other day, talking to a colleague who was much younger than me, I discovered that we had somewhat similar sentiments. Mine are summarized as follows. I hope it’s just a mood.

Neoclassical finance, the entire structure that includes the efficient market model, Brownian motion, stochastic calculus, the capital asset pricing model, and of course Black-Scholes-Merton, is a beautiful comprehensive far-reaching discipline. It describes a risky system and its consequences elegantly and sparely, and provides lots of insight. I like it. Unfortunately, the real world is more complicated.

One of the responses to that complexity is behavioral finance. This started out with prospect theory as an attempt to provide a comprehensive new foundation for finance and economics. It hasn’t turned out that way. That part of behavioral finance is by and large ignored. Instead, its proponents have streamed off into two directions. The first is neuro/psycho finance, filled with papers discussing brain scans of traders and their risk appetite, which isn’t really finance at all, but belongs (if it belongs anywhere outside of grant applications) in a psychology department. The second is the study of how people react to choice, a collection of mildly interesting statistical studies of CEOs and investors that mostly confirm what everyone knew before, and whose results are most useful in justifying various paternalistic social policies. None of it adds up to a comprehensive discipline; it seems to be mostly strategies for writing papers.