For Spinoza, emotions are not lodged in a separate body in conflict with the soul, since soul and body are aspects of a single reality; but emotions, as affections of the soul, make the difference between the best and the worst lives, as they either increase the soul's power to act, or diminish that power.

In other models, emotions as a category are apt to be sucked into either of two other faculties of mind.

Some treat emotion as one of many separate faculties.

But then this is an issue on which cognitive science alone should not, perhaps, be accorded the last word: what to a neurologist might be classed as two tokens of the same emotion type might seem to have little in common under the magnifying lens of a Marcel Proust.

Other models propose mutually conflicting ways of locating emotion within the general economy of the mind.

So it is not surprising that most of the great classical philosophers—Plato, Aristotle, Spinoza, Descartes, Hobbes, Hume—had recognizable theories of emotion, conceived as responses to certain sorts of events of concern to a subject, triggering bodily changes and typically motivating characteristic behavior.

What is surprising is that in much of the twentieth-century philosophers of mind and psychologists tended to neglect them—perhaps because the sheer variety of phenomena covered by the word “emotion” and its closest neighbors tends to discourage tidy theory.

They are then treated as mere composites or offshoots of those other faculties: a peculiar kind of belief, or a vague kind of desire or will.

The Stoics made emotions into judgments about the value of things incidental to an agent's virtue, to which we should therefore remain perfectly indifferent.How do emotions fit into different conceptions of the mind?One model, advocated by Descartes as well as by many contemporary psychologists, posits a few basic emotions out of which all others are compounded.Most emotions have an intentional structure: we shall need to say something about what that means.Psychology and more recently evolutionary biology have offered a number of theories of emotions, stressing their function in the conduct of life.level of arousal, intensity, pleasure or aversion, self- or other-directedness, etc.).