ABSTRACT
No theory can claim to explain everything. Theories are systematizations of sufficient conditions that can account for the occurrence of an effect, but hardly any psychological theory can exclude the possibility that the same effect may also originate from other causes or processes. Being aware of this methodological truism is important to avoid misunderstandings in any theoretical debate, and in particular for this book. Two theories are incompatible neither if they predict different phenomena nor if they predict the same phenomena for different reasons. A crucial test between two theories is only possible when they predict different outcomes under the very same conditions. When comparing theories of affect and cognition, it is thus essential to be specific about the domain and about the truly distinct predictions of different conceptions.
