Heterophenomenology is a term coined by Daniel Dennett to explain an explicitly third-person, scientific approach to the study of consciousness and other mental phenomena. It consists of applying the methodology with an anthropological bent, combining the subject’s self-reports with all other available evidence to work out their psychological state.
Heterophenomenology is put forth because of the alternative to traditional Cartesian phenomenology, which Dennett calls “lone-wolf neurophenomenology” to stress the very fact that traditional phenomenology accepts the subject’s self-reports as being authoritative.
In contrast, heterophenomenology considers the themes authoritative only about how things seem to them. It doesn’t dismiss the Cartesian first-person perspective, but rather brackets it in order that it are often intersubjectively verified by empirical means, allowing it to be submitted as scientific evidence.
The method requires a researcher to concentrate on the themes and take what they assert seriously, but to also check out everything else available to them, including the subject’s bodily responses and environment, evidence provided by relevant neurological or psychological studies, the researcher’s memories of their own experiences, and the other scientific data which may help to interpret what the topic has reported.
Dennett notes this method is really the traditional way that anyone will prefer to investigate aspects of the mind. He writes heterophenomenology is nothing new; it’s nothing aside from the tactic that has been employed by psychophysicists, cognitive psychologists, clinical neuropsychologists, and almost everybody who has ever alleged to study human consciousness during a serious, scientific way.
The key role of heterophenomenology in Dennett’s philosophy of consciousness is that it defines all which will or must be known about the mind. For any phenomenological question why do I experience X, there’s a corresponding heterophenomenological question why does the topic say ‘I experience X.
The total set of details of heterophenomenology, plus all the info we will gather about concurrent events within the brains of subjects and within the surrounding environment, comprise the entire data set for a theory of human consciousness. It leaves out no objective phenomena and no subjective phenomena of consciousness.