"Western Reductionism" is a working term for the idea that with enough resources "everything is dissect-able" to find out why it works by studying and measuring the individual parts and seeing how it affects the whole and vise verse. StepwiseRefinement is an example of such a view.
In science it is representative by the practice of holding every variable but one constant to study each variable one a time in terms of the known levels of the other (constant) variables. This is then compared to the model(s) to measure fit. (Perhaps a practical use for EveryCombinationInManyProgrammingLanguages.)
WR tends to conflict with what may be called "eastern thought" and holism (as in "holistic" medicine). In these, one "feels" the correct answer using a combination of experience and wisdom and perhaps meditation. These tend to put a higher value on ArgumentFromAuthority.
Reductionism was discovered as successful strategy to conquer nature by the Enlightenment. And that happened in western society. So western in WesternReductionism is redundant. I assume you put it in to make a WikiWord. Reductionism doesn't neccessarily hold one variable fixed, though where possible this significantly simplifies matters.
For now I'll leave it as a standing working definition because it covers more than physical reduction, such as logical and statistical reduction. -t
See also http://en.wikipedia.org/wiki/Reductionism