[mellavora]

> If you mean the mental/emotional state necessary for a human to act without regard for consequences of their actions to other people, then computers are not ruthless.

I don't understand, what am I missing?

I've never seen a computer have any regard for the consequences of its decisions. Computers are thus completely ruthless.

[aordano]

I think the GP points to the fact that given the inability of computers to evaluate the consequences of its programming, ruthlessness is a concept that cannot apply to them because by definition involves disregard about those consequences, not ignorance.

edit: typo

[Avicebron]

I think there is a conflation of malicious and ruthlessness in this thread, showing no pity or compassion (def of ruthless) does apply to a computer because they can do neither. However, being actively malicious and disregarding consequences probably only applies to humans controlling them because the computer is ignorant of those consequences as you say.