Oregon Shooting - Guess why?

[Thumpalumpacus]

It seems like prima facie evidence of derangement to me, acting out in such a manner.

In a colloquial sense you are correct, however, I think that if we're talking in clinical terms it's not so simple.  I'm no expert, but I'm pretty sure killing ten people doesn't automatically make you mentally ill.  I bet his method probably indicates some mental illness, however, and I wouldn't be surprised if he has gone undiagnosed.  But I don't think it's correct to assume at this point that he was for sure mentally ill.

A fair point; I'm certainly being colloquial in my use of the word "derangement", rather than "mentally ill".

Assuming his mental illness is an easy thing for me to do, and your point is well-aimed; however, I do think that the weight of experience gives my own point (and the others who have made similar points) more heft. After all, mass murder is not normal behavior; the assumption of derangement seems fair simply because the behavior is so out-of-bounds.

I'm not talking in clinical terms, because I don't have the education, authority, or experience to do so.