I had actually been wondering about this recently. People define a psychopath as someone with no empathy, and then jump to "therefore, they have no morals." But it doesn't seem impossible to value something or someone as a terminal value without empathizing with them. I don't see why you couldn't even be a psychopath and an extreme rational altruist, though you might not enjoy it.
Is the word "psychopath" being used two different ways (meaning a non-empathic person and meaning a complete monster), or am I missing a connection that makes these the same thing?
I don't understand that connection you made. Care to explain?
You can't determine someone is a psychopath via a brain scan yet. You can't even determine someone has Alzheimer's with only a brain scan, even though it's pretty well understood which brain regions are damaged in the disease. Psychopathy is a syndrome, and still quite poorly understood. Note also that there would be significant problems with testing if he went to a psychiatrist after knowing his scan results.
I think that neuroscientist is just trying to make money by claiming he's a psychopath, which of course would be quite a psychopathic thing to do :)
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.