Emotions play an extremely important role in human mental life – and perhaps because of this, we are sometimes fascinated by the idea of intelligence without emotion. Like Mr. Spock in the original Star Trek, or Mr. Data in the newer Star Trek -- an alien and robot respectively, who are more intelligent than most humans yet lack the feeling-driven component of human behavior (Spock however is much more appealing and moving than Data, to most of us, precisely because he does have emotions, they're just generally repressed and not a controlling factor in his mind or life.)
But are emotionless intelligences really possible? To what extent is human emotion a consequence of our particular evolutionary heritage, and to what extent is it an aspect of Mind In General?
Clearly, much of human emotional life is distinctly human in nature, and not portable to systems without humanlike bodies. Furthermore, many problems in human psychology and society are caused by emotions run amok in various ways – so in respects it might seem desirable to create emotion-free AI’s one day.
But there are limits to the extent to which this will be possible. Emotions represent a critical part of mental process, and human emotions are merely one particular manifestation of a more general phenomenon – which must be manifested in some way in any mind.
The basic phenomenon of emotion is something that will exist in any mind that models itself as having some form of "free will", and may be conceptualized as
An emotion is a mental state that does not arise through a feeling of "will" or "autonomy", and is often accompanied by physiological changes
Human emotions are elaborations of this general “emotion” phenomenon in a peculiarly human way.
There are a few universal emotions – including happiness (and hence unhappiness) and pain – which any intelligent system with finite computational resources is bound to experience, to an extent. And then there are many species-specific emotions, which in the case of humans include rage, joy and lust and other related feelings.Controlling our emotions is, by definition, never going to be fully possible. However one can certainly adopt a mental dynamic in which emotions are not the controlling factor -- in which spontaneous emotional arisings are incorporated in a high-level ratiocination process, and thus don't affect action on their own.
In other words: Spock is possible; Data probably not. Even a highly rational digital intelligence would probably be more Spock-like than Data-like, even if its flavors of emotion were less humanlike than Spock's.