Biology is the study of living things. Science is the gathering of verifiable, reproducible knowledge about the world. Done well, science matches its tools to the problem at hand, so that its discoveries can be meaningful. Psychiatry is the branch of medicine dealing with thought, feeling, and behavior: the content and organization of subjective experience. The term biological psychiatry has been used to denote a scientific approach to psychiatry, incorporating what is known about the biology of behavior. The term is sometimes used to refer narrowly to biochemistry and quantified measures of behavior; yet psychiatry and behavior become empty, if meanings and feelings are omitted from the field of observation. To be truly biological, psychiatry must integrate all relevant disciplinary perspectives:
Behavioral psychology − the use of systematic observation, sometimes called "experience-distant" due to focus on observation, rather than empathic engagement.
Hermeneutics - the meaning of experience. Part of the wonder of the brain is that it links thought and action: perception stimulates thoughts and feelings, understanding and excitement; and these in turn lead to action.
Psychoanalysis − also involves systematic observation, with focus on experience.
Anthropology, sociology, and ethology - the study of cultures, and even of other species. Some behaviors once thought to be uniquely human, such as altruistic caring for the young, or the infant's distress on separation from mother, can be found − often, with enlightening variations − in other species.
Neurobiology − physically identifiable anatomy, structure, chemistry, genetics, and development. Mood, behavior, and consciousness are emergent properties, arising out of the physical substrate of the brain. The subfields of aeuroanatomy and neuroimaging are rich current sources of new information. These physical sciences have generated rich information on the functional organization of the brain, and sometimes shed light on aspects of the mind.
Systems theory − an abstract, mathematical way of formulating ideas about how interactions within complex systems. This field has helped us understand why emergent properties (like consciousness, or which team will win the World Series) are so hard to predict from knowing the underlying structure (like brain anatomy, or the rosters of the major-league teams). Like psychoanalysis and physics, it has generated helpful concepts that we sometimes use without remembering where they came from. We use terms like linear, nonlinear, and deterministic, both as descriptive organizers and as metaphors.