Why is there no physics forum at the level of Mathoverflow?

If you aren’t already aware, some of the highest-level discussion about math can be found over at Mathoverflow. The questions are all research-level. The quality of answers is very high and some of the best mathematicians in the game, including several Fields medallists, routinely participate in the discussion.

Here is a puzzle then: why isn’t there any physics forum operating at this level? Physics StackExchange is good, but nowhere close to Mathoverflow.

I offer a few, not-mutually-exclusive, hypotheses:

1. People don’t understand physics as well as they understand math. Especially everyday physics, such as: why are clouds white or why do all the planets orbit in the same plane. These require a combination of physical intuition and mathematical ability. In this sense, physics is harder than math: it is easier to frame interesting physics questions which have difficult answers than it is to frame interesting math questions with hard answers (Yes, number theory is an exception). Indeed, you need little physics training to ask why the sky is blue or why do sand-dunes form.

2. The language of math is easier to communicate in. You need less words and more symbols in math. But in physics, you need more words. So you need people who are especially clear in communicating physics ideas. This is a skill that is harder to acquire than communicating mathematical ideas. Therefore, if you compare a physicist and a mathematician who both understand their domain equally well, then it is more likely that the mathematician communicates better.

3. Curiosity about math is easier to develop than curiosity about physics. I know this sounds counter-intuitive. But I’m talking about deep curiosity, the kind of curiosity that makes you explore answers yourself. Deep curiosity about physics requires a kind of naive curiosity about everyday things: you need to look around, go pick up things and play with them. This is socially visible and this kind of naivety is looked down upon; it is the opposite of nil admirari. But deep curiosity about math is easier to develop. You can do it in privacy. Just pen and paper. Thus, less people have developed a good intuition about physics.

4. Curiosity about math is more easily rewarded. The answers you get are clear and satisfying. But in physics, you are never sure if the explanation that you came up with corresponds to reality or whether you’re missing some important subtlety. To check, you have to find a way to test your hypotheses with real world observations. In the case of math you can get a crisp answer: a proof or a counter-example.

5. The physics education system isn’t very good at inculcating all of these abilities because they are harder to teach. Interestingly, on internet physics forums such as the old Orkut physics forum and Physics Stack Exchange (I’m not sure about physicsforums.com) the best explainers were, in some sense, outsiders (i.e. outside academia). Ron Maimon comes to mind. I forget the name of the best explainer in Orkut physics, but I remember clearly that he was a high-school dropout.

6. Historical reasons. Mathoverflow just became more famous because of all the famous mathematicians who came there. But, many famous physicists did try to come to Physics StackExchange as well.  Examples: t’Hooft, Shor, Preskill, Gottesman.

This smells of opportunity. If these abilities: naive curiosity, thinking about more unstructured real life problems using hypothesis testing, intuition, and a mix of math and numerical estimation,and the ability to communicate clearly with both words and equations, are rare, then that means that this is a potentially a rare and valuable skill worth developing.


Book Review: ‘Violence’ by Randall Collins

Randall Collins is an ambitious sociologist. His aim is to build a comprehensive theory of violence, in all of its different manifestations. This includes violence in military contexts, police brutality, mugging, bullying, domestic abuse, violent carousing, violent sports such as boxing, violence during sporting events such as fights during a baseball match or audience violence after a football match, dueling in the 19th century, and even mosh pits.

The thesis that connects all these manifestations of violence? Violence is very hard for humans.

He proposes that all human beings whenever put in a situation that is potentially violent, come up against a wall of “confrontational tension and fear”. This is his primary theoretical construct. The source of this confrontational tension/fear is not explored in detail; he proposes that it is a consequence of attempting to override fundamental human instincts towards mutual emotional entrainment and instincts towards engaging in solidarity rituals. Importantly, it is not just fear of injury or death. This is evidenced, for example, by the fact that soldiers in battle experience much more fear than medics in battle, though they have similar exposure to danger.

If we accept this fundamental difficulty to committing violence, then his task is to illustrate the situations in which some people are able to overcome the tension/fear and proceed to violence. His focus is always on the situation and far less on background factors such as race, socioeconomic status or criminal history. As he repeatedly points out, background factors only account for very little in the causes of violence: most poor people do not commit crime; most criminals are not violent; most drunken people do not carouse violently; most police arrests do not turn violent; most young men are not violent; most child-abuse victims are not violent and so on.

He proposes different and varied situational pathways that allow people to overcome confrontational-tension/fear. For example, most police brutality incidents, such as the famous Rodney King incident, can be seen as a case of ‘forward panic’: a situation where tension builds up—the high-speed chase, in the case of Rodney King—due to the threat of violence and it is released all of a sudden when one party—the police, in this case—realize that they are much more stronger than the other party—King, in this case. The released tension leads to ugly and brutal violence unleashed by a strong party upon a weaker party.

Forward panics produce the most viscerally ugly forms of violence: take the classic example of police beating up a lone protestor. The Rape of Nanking is another famous example, and is analyzed in the book. The Jallianwallah Bagh massacre also comes to mind, though it is not mentioned in the book.

In bullying and in domestic abuse, the confrontational-tension/fear is overcome by repeated emotional entrainment. The bullied—over a period of time—get trained in their relation to the bully. They ‘learn’ to play the role of the victim. Collins points out that most bullying happens in “total institutions”: closed-off institutions whose status hierarchies do not change over time, and there is little opportunity for participants of the institution to go somewhere else. The classic examples: prisons, high-schools and families. In total institutions there are more opportunities for both bullies and the bullied for repeated interaction and thus repeated emotional training.

And similarly, he dissects dozens of forms of violence. The overarching theme is that violence is hard. Violence needs certain situational variables to be conducive. And even when it is conducive, violence is usually limited to a very small number of people and is generally incompetent. A striking example: on average, only 15% of frontline US Army troops during World War II even fired their guns.

As any good theorist, he realizes that there are exceptions to any rule and he tries to understand them. For example, some military snipers have a fantastic record of kills, far more than most people in the fighting force. Similarly, ace pilots and famous mafia hitmen. All of these are among the very few people in the world who are competently violent.

What situational dynamics makes this possible? Snipers for instance, operate under cover, very far away from the enemy and never making eye contact: this allows them to overcome confrontational-tension/fear. Similar mechanisms are proposed for other competently violent people.

Overall, this is a fantastic book. It is beautifully written and the language is kept as plain as possible. I’m not a sociologist, but I was able to understand most of this book clearly. Whether his theory is successful or not is an open question.

His analysis is always honest, and he is always willing to look at the exact places where his theory seems to fail. And he is willing to accept the parts that his theory does not explain. In fact, he hints at a much broader theory that would simultaneously account for both background and situational variables.

I worry whether some of his explanations about how confrontational-tension/fear is overcome aren’t too contrived. He repeatedly points out that most situations that have conflict do not proceed to violence. And he attempts to clarify the situational dynamics which allows violence. While definitely he goes some way in explaining the dynamics, I don’t know if he really completes the picture. But then again, he says that he is setting up a companion volume to this.