Two Alternative Scientific Paradigms
A fundamental distinction can be drawn between 'objectivist' and 'subjectivist' approaches to science (and, in our case, to studying health).
Objectivism. From the objectivist viewpoint, phenomena exist outside of the person who is observing them and, using the tools of scientific investigation, the goal is to observe and understand phenomena as objectively as possible. The researcher is independent from what is being observed; science should be pursued objectively, research methods must be standardized and investigation is a value-free pursuit of the truth. Applying this paradigm to health, people are seen as passive objects of study (as typified by Talcott Parsons who described the patient as submitting to the doctor's treatments, complying with therapy, etc.) Other examples include discussions of health 'determinants,' suggesting that people's health is inescapably predicted by external forces beyond their control. In the field of health measurement there is an emphasis on objective, laboratory-based measures.
All went well until the early part of the twentieth century when particle physics increasingly came to recognize that things do not appear to function in such a predictable fashion. Light appears to behave both as particles and as waves; photons appear to be able to pass through two slits in a box simultaneously; Heisenberg pointed out the uncertainty principle, in which we can never learn the actual state of anything, for by making measurements we disturb reality and change it. Hence, the observer modifies what he measures; science cannot be objective and detached from reality. This had clear echoes in the social and health sciences, where it is evident that we cannot (for example) ask questions about someone's health without modifying what they say.
Subjectivism, therefore, came to form an alternative paradigm in which reality has important subjective elements; it is not completely distinct from the observer. The observer's expectations modify what they see; the interpretations they make of "reality" are influenced by their mindset, which is, in turn, influenced by their training and the broader culture in which they operate; the questions they study in the first place are largely determined by scientific fashion, and by what is considered "fundable research" by the granting agencies. This brings the researcher back into the picture; humans have agency. At the same time, in medicine the patient was being brought back in: we began to combine subjective (patient-assessed) and objective (laboratory-based) measures of the outcomes of care; doctors involve patients in making decisions about therapeutic alternatives, and so forth. In terms of research methods, the idiographic methods, often applied in qualitative studies, came to supplement the nomothetic approach of positivist science.
These alternative viewpoints are illustrated in the accompanying table which was prepared by Dr. Geneviève Rail.
Links to a discussion of positivism in the social sciences; link to description of Complexity theory
Overview of History of Science in the life sciences