reductionism - Varieties of reductionism, History

In philosophy, an attempt to explain or define one set of concepts or theories in terms of another which is more basic or less complex. For example, the view that human behaviour can be ‘reduced to’ animal behaviour, or animal behaviour to the physical laws of matter (so that psychology and biology reduce to physics).

Reductionism in philosophy is a theory that asserts that the nature of complex things is reduced to the nature of sums of simpler or more fundamental things.

Reductionism is often understood to imply the unity of science. For example, fundamental chemistry is based on physics, fundamental biology is based on chemistry, psychology is based on biology, sociology is based on psychology, and political science and anthropology are both based on sociology.

In his book The Blind Watchmaker, Dawkins introduced the term "hierarchical reductionism" (p. He provides the example of a computer, which under hierarchical reductionism can be explained well in terms of the operation of hard drives, processors, and memory, but not on the level of AND or NOR gates, or on the even lower level of electrons in a semiconductor medium.

Varieties of reductionism

There are several generally accepted types or forms of reduction in both science and philosophy:

Ontological reductionism is the idea that everything that exists is made from a small number of basic substances that behave in regular ways (compare to monism). There are two forms of ontological reductionism: token ontological reductionism, and type ontological reductionism. Token ontological reductionism is the idea that every item that exists is a sum item. For perceivable items, it says that every perceivable item is a sum of items at a smaller level of complexity. Type ontological reductionism is the idea that every type of item is a sum (of typically less complex) type(s) of item(s). For perceivable types of item, it says that every perceivable type of item is a sum of types of items at a lower level of complexity. Methodological reductionism is the idea that explanations of things, such as scientific explanations, ought to be continually reduced to the very simplest entities possible (but no simpler). Occam's Razor forms the basis of this type of reductionism. In the first definition it is the idea that the terms of a theory of science A referring to objects at a higher level of complexity than the objects of science B can be replaced by the terms of science B. In the second definition of theoretical reductionism the older theories or explanations are not generally replaced outright by new ones, but new theories are refinements or reductions of the old theory into more efficacious forms with greater detail and explanatory power. Scientific reductionism has been used to describe all of the above ideas as they relate to science, but is most often used to describe the idea that all phenomena can be reduced by scientific explanations. It is useful to note in addition that there are no explicit theories that reject token ontological reduction of biological items to chemical items, or that reject token ontological reduction of chemical items to physics items. Set-Theoretic Reductionism is the idea that all of mathematics can be reduced to set theory. He than proposed his own form of reductionism, logicism, which in turn was famously disproven by Russell's Paradox. Many believe that Godel's Incompleteness Theorem proves that reductionism in mathematics is impossible (since all systems cannot be both complete and consistent at the same time), but there is still a great deal of debate on the matter. Linguistic reductionism is the idea that everything can be described in a language with a limited number of core concepts, and combinations of those concepts. The term "greedy reductionism" was coined by Daniel Dennett to condemn those forms of reductionism that try to explain too much with too little. Eliminativism is sometimes regarded as a form of reductionism. Eliminativism is often regarded as a form of reductionism, since the eliminated theory is at some point replaced by a theory referring to the objects that were not eliminated. For example, Richard Jones in a systematic study of reductionism in philosophy, the natural sciences, the social sciences and religion differentiates five types: substantive, structural (causal), theoretical, conceptual (descriptive), and methodological.

The denial of reductionist ideas is holism: the idea that things can have properties as a whole that are not explainable from the sum of their parts. Phenomena such as emergence and work within the field of complex systems theory are also considered to bring forth possible objections to some forms of reductionism. It's worth noticing that they don't object to token ontological reduction of biology to chemistry, nor to token ontological reduction of chemistry to physics.

Outside the field of strictly philosophical discourse and outside the fields of biology, chemistry and physics, the best known denial of reductionisms of whatever kind is religious belief, which, in most of its forms, assigns supernatural original causes to phenomena. It is worth asking how religious systems regard token biological reduction of biological items to chemical items and chemical items to physics items.

History

The idea of reductionism was introduced by Descartes in Part V of his Discourses (1637).