This is a subject I often think about...
...maybe 'worry about' is more like it.
I can't improve on the points Frank and Robert make, but a couple weeks ago I was noodling around on this subject and came across this
It's from MIT’s Department of Brain and Cognitive Sciences, and discusses recent work suggesting a persons sense of morality, can be turned off by application of an EM field to a brain center called the right temporo-parietal junction.
Interesting, to be sure,...but not very comforting.