Here's a post on another forum arguing that emotion is an essential part of our minds:
Nope. There are people who suffer the loss of one or all emotions due to brain damage or birth defects and that isn't what happens. For one thing, they don't care about their own best self interest; that too is an emotional impulse. Without emotion they care about gratifying their senses since that's all they have left as a motivation; and they don't care about the future consequences to themselves or anything else. They'll spend all the money they have on food, liquor, drugs & prostitutes because those things feel good right now, even if they know that they are going to run out of money in the future, since they aren't capable of caring about the future. They can't even win a game; they can tell you how to win if asked, but they themselves will just fiddle around aimlessly since they don't care if they win or lose. Interestingly, they also tend to get stuck in "loops" oscillating between several choices; unlike a normal person they just keep going round and round until hunger or some external influence breaks them out of the loop since they don't get frustrated.
Now, a high functioning psychopath might act like you describe; but they still have some emotions, they are just all self interested ones.
Human minds ultimately are built with the "design assumption" that emotions are part of the reasoning process; without emotions our minds are crippled. Some artificial intelligence built from scratch might be able to get by on pure intellect, with the functions we use emotions for replaced by some form of reasoning; but we can't.
(Emphasis mine.) I wish the poster had supplied a cite, but his argument makes sense to me.
Emotions: Can't live with 'em, can't live without 'em? Or is it simply can't live without 'em?