Their dialogue can be found here. Every time that I have seen a video of Robin Hanson or Tyler Cowen versus anybody they have dominated the conversation, so I was naturally excited to see these two giants spar. Tyler had a sly smile on his face for much of the hour, and Robin often sported an incredulous look. I call them by their first names although I have never met either of them because when you read somebody's blog for long enough you come to believe that you know them. Here are some notes and reactions:
1) Robin says that although it hard to conclusively say anything, you shouldn't just throw your hands up and say "nobody should know anything." I agree with this and I had not yet seen it so succinctly articulated. It is the reason why I find much of the Socratic "he who admits he knows nothing is the smartest" stories fairly dumb.
2) The difference between unmediated versus mediated intuition is a measure of how much evidence you can point to that accounts for your intuition. They both quickly agree that most of their thinking is done by unconscious processes that they do not notice and cannot control. This premise allows them to focus on how they formed their beliefs instead of the less manageable question of why.
3) Tyler's critique of cryonics draws substantially from Nick Bostrom's infinite ethics argument, which is based upon a current interpretation of quantum physics. Whether the merits of this argument are valid or not, Tyler's hobby horse of probabilistic ethics is endlessly fascinating and serially under discussed.
4) Tyler on medicine: "I think what works is setting bones, some number of pharmaceuticals, attitude, high social status, and exercise, and sanitation." He thinks that some visits to the doctor have a zero and maybe even negative marginal return. As much as I agree with some of these conclusions, I cannot help but attribute much of the recent increase in life expectancy to some of these doctor visits. Perhaps I am biased.
5) Tyler thinks cryonics has a low chance of working in part because of the impact of hormones from non-brain areas ("the gut") affecting the brain. There is some basis for this, as there is biofeedback throughout the body and it is complicated. Nevertheless, I think that the larger stepping stones will be found in actually scanning the neurons and glial cells at a molecular level. Compared to that, simulating the body environment does not strike me as nearly as difficult.
6) At one point they begin rattling off movies in order to discuss one of them, but they have not seen many of the same movies. That used to happen to me all the time and was the source of such frustration that I decided to watch the most discussed and best movies of all time--imdb's top 250. I now am the king of these conversations.
7) Robin think that economists are admirable because they weigh the interests of different people in a moderately neutral way. You can neglect individual measures of loyalty and group association at a large scale because at that level they cancel out and are no longer instrumentally useful in economic models, making self-interest the primary variable of interest. Although this approach makes some admittedly false assumptions, Robin argues that economists are on the whole scientific and willing to use an alternative technique if theirs is shown to be inferior. Economists are indeed at least somewhat scientific so it is a question of degree; Tyler thinks they aren't introspective enough about the potential falsehood of their premises.
8) Robin offers a nasty one-two punch at the end of the debate. He first ensnares Tyler by asking whether those who achieve high levels of influence tone their ideas down in order to appease the now reachable masses, which Tyler agrees with. Robin then asks whether Tyler himself has fallen victim to this de-weirdification process as his fame has risen (note that MR is top 100 on Technorati), and if not, what separates him from the others? He presents a paradox for Tyler: admit to either believing himself to be special or having sold out. Robin spits hot fire.
9) Should you discuss topics on which you are not an expert? Robin apparently thinks not, thus justifying his refusal to make macroeconomic forecasts. His willingness to discuss topics selectively makes him unique--he is one of the first people I have seen who admits that they do know something about the recession without entering into a discussion of the causes. In fact, I have seen many people who admit they know nothing about the crisis and still espouse a pet theory. But in general I'm worried that it is cripplingly hard to pinpoint when you have become an expert and thus waiting for that moment is foolhardy. I would argue that it is better to submit your thoughts to the court of public opinion, but perhaps I am sorely mistaken.
10) Tyler says that having read the canon of classics is correlated with the ability to conduct intelligent conversation and have a nuanced understanding of simulations, just as it is important to have some knowledge of economics. Robin on the other hand thinks fiction is somewhat overrated; when asked for book recommendations he once responded "textbooks."
11) At the "meta" level, Tyler has an intuition and lobs out various reasons for why he holds it, smugly confident that even when he cannot fully explain his position he must feel it for some reason and thus it is not his fault if the other person cannot grasp or find those same reasons. Robin is frustrated by this technique, but even when discussing the technique itself Tyler remains confident in his own intuition, so there is little that Robin can do. Tyler's approach is indeed dangerous, because how can you be sure that you have seen all of the evidence before forming your intuition? The only way to justify such a strategy is if you are insatiably curious, and in Tyler we trust.