A philosophical strategy by which one set of facts or events is thought unnecessary because of the existence of another, more fundamental, set of facts or events.
The term is often used in a pejorative sense; that is, a position will be described as “reductionistic” because it tries to make things more simple than they really are by reducing what should be a complex phenomenon to only one of its components.
But not all reductions are bad—for example, reducing chemistry to physics. A contentious reduction is the claim that the existence of immaterial mental entities (minds) is an unnecessary postulate. Eliminative materialists believe that all mental events could be explained in terms of events about material states (brain waves, neural processes, etc.).
Christian theology has also been guilty of various reductionist strategies—sometimes reducing the miraculous to the natural (Bultmann), or reducing revelation to inspiration (Schleiermacher), or reducing revelation to divine dictation. Given the complexity of creation, Christian theology should expect our theoretical accounts of the world to honor this creational complexity rather than oversimplifying it.
Excerpted from 101 Key Terms in Philosophy and Their Importance for Theology, Kelly James Clark, Richard Lints, James K. A. Smith (Westminster John Knox Press, 2004), 80-81.