reductionist

""...the theory that every complex phenomenon, esp. in biology or psychology, can be explained by analyzing the simplest, most basic physical mechanisms that are in operation during the phenomenon."" -- Source: reductionist. Dictionary.com. Dictionary.com Unabridged (v 1.0.1), Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006. http://dictionary.reference.com/browse/reductionist (accessed: November 27, 2006).

See reductionism.