Reductionism

Reductionism is a viewpoint that regards one phenomenon as entirely explainable by the properties of another phenomenon. The first can be said to be reducible to the second. It is a mere epiphenomenon of the second. It is really just another name for the second. It has no distinctive properties that require a distinctive theory or methodology.

For example, biological reductionism claims that the mind is explained entirely by physical properties of the brain, that the mind is physical, that what we call mental is really just another term for the brain, that mental/mind is actually only an epiphenomenon of the brain, that it can and should be studied by neurophysiologists, that there is nothing distinctively psychological about the mind, and that treating the mind as having properties distinct from those of the brain is an illusion.

An opposite form of reductionism is sociological reductionism. This reduces psychological phenomena to epiphenomena of social factors. In this view, psychology is determined entirely by nationality or social class. There is nothing to psychology besides the properties it acquires from one's nationhood or class. In this view, one may speak of U.S. psychology as a homogeneous phenomenon or lower-class psychology as a homogeneous phenomenon because no other factors determine psychology; it is reducible to social state or social class.

Another form of reductionism that bears directly on qualitative methodology is quantitative reductionism. The claim here is that qualitative characteristics of personality, emotions, and reasoning are entirely expressible in quantitative terms. An example is the notion of intelligence. IQ is construed as an entirely quantitative dimension. IQ can range from low to high. The only meaningful way to discuss IQ is in terms of its quantitative amount. IQ is reducible to quantity. Psychologists are concerned with operationalizing intelligence and measuring it, not with discussing theories about what it is.

Reductionism denies complex multiplicity and heterogeneity in favor of a single kind of phenomenon or factor. For example, biological reductionism construes the mind as continuous with the single realm of neurophysiology. It does not recognize the mind as a complication of neurophysiology that introduces a new kind of phenomenon.

Quantitative reductionism similarly simplifies psychology by recognizing only one order of reality, the quantitative order. Qualitative complexity and multiplicity is reduced to simple quantitative differences.