 One question that has divided emotion theorists is: Which subset of the evaluative, physiological, phenomenological, expressive, behavioral, and mental components is essential to emotion? The answer to this “problem of parts” (Prinz 2004) has changed at various times in the history of the subject, leading to a vast collection of theories of emotions both in philosophy and in affective science. Although such theories differ on multiple dimensions, they can be usefully sorted into three broad traditions, which we call the Feeling Tradition, the Evaluative Tradition and the Motivational Tradition (Scarantino 2016).