Heterophenomenology

Heterophenomenology ("phenomenology of another not oneself"), is a term coined by Daniel Dennett to describe an explicitly third-person, scientific approach to the study of consciousness. It consists of applying the scientific method with an anthropological bent, combining the subject's self-reports with all other available evidence to determine their mental state. The goal is to discover how the subject sees the world and themselves, without taking the accuracy of the view for granted.

Heterophenomenology is put forth as the alternative to traditional phenomenology, which Dennett calls "autophenomenology" to emphasize the fact that it accepts the subject's self-reports as being authoritative. In contrast, heterophenomenology considers the subject authoritative only about how things seem to them.

In other words, heterophenomenology requires us to listen to the subject and take what they say seriously, but to also look at everything else available to us and be ready to sometimes conclude that the subject is wrong even about their own mind. For example, we could determine that the subject is hungry even though they don't recognize it themselves.

The key role of heterophenomenology in Dennett's philosophy of consciousness is that it defines all that can be — or needs to be — known about the mind. To quote Dennett, "The total set of details of heterophenomenology, plus all the data we can gather about concurrent events in the brains of subjects and in the surrounding environment, comprise the total data set for a theory of human consciousness. It leaves out no objective phenomena and no subjective phenomena of consciousness."