I would expect to find people with very skewed senses of reality (as seen in schizophrenia). I don't consider that the same as a preference. What's currently called antisocial personality disorder, also known as psychopathy or sociopathy, I might consider more a preference (in that it deals with how they value other people's wellbeing, not from their perception of reality).
Thanks for the serious response. I see what you mean. My unease about these kind of explanations is the asymmetry between the kinds of terms used to explain why someone would choose to commit a horrible act and the kinds of terms used to explain why someone wouldn't choose to commit a horrible act. After rethinking it though, I agree that making reference to beliefs in addition to preferences does add explanatory power, but I'm not very certain of this. After all, we make reference to the same physical laws to explain why a bridge stays up as when it falls down; but when we explain "normal" behavior, we talk about preferences and constraints, without saying anything about having non-schizophrenia.
I wouldn't be surprised to hear that someone who attacked strangers for no apparent reason was experiencing delusions or hallucinations. I would be surprised to hear that someone with sociopathy did so, because they normally hurt people only for personal gain, and there's nothing to gain from opening fire on a crowd.
And yet, fame is a very common preference among humans and this guy is now world famous (he even has his own thread on Less Wrong!). Depending on how strong his fame-preference is, we can't rule out that these tactics weren't instrumentally rational in his particular case.
Hearing voices is not a preference.
Maybe, IDK. Do you never hear voices? I hear a voice (it sounds very similar to my normal speaking voice, but not exactly). As far as I can tell, this is just what linguistic thinking feels like from the inside. I can even make it go away by using my visual imagination, doing strenuous physical exercise, or practicing mindfulness meditation. The extent that I do make it go away seems to be determined by my personal preferences and the constraints imposed by my environment.
After all, we make reference to the same physical laws to explain why a bridge stays up as when it falls down; but when we explain "normal" behavior, we talk about preferences and constraints, without saying anything about having non-schizophrenia.
I don't understand the analogy. Explanations why a bridge stays up usually point out different physical laws than explanations why it had fallen down. You rarely hear "the bridge stays up because the construction hasn't corroded and the engineers made no mistake", unless there is a reason to suspect something wrong with the bridge.
A Ph.D student in neuroscience shot at least 50 people at a showing of the new Batman movie. He also appears to have released some kind of gas from a canister. Because of his educational background this person almost certainly knows a lot about molecular biology. How long will it be (if ever) before a typical bio-science Ph.D will have the capacity to kill, say,a million people?
Edit: I'm not claiming that this event should cause a fully informed person to update on anything. Rather I was hoping that readers of this blog with strong life-science backgrounds could provide information that would help me and other interested readers assess the probability of future risks. Since this blog often deals with catastrophic risks and the social harms of irrationality and given that the events I described will likely dominate the U.S. news media for a few days I thought my question worth asking. Given the post's Karma rating (currently -4), however, I will update my beliefs about what constitutes an appropriate discussion post.