In general, a philsophical trend which denies or minimizes purpose in the universe, and seeks to explain all phenomena solely by efficient causality.
It is based on the extreme simplification of all reality into matter and motion and is the apparent aim of physical science, following Descartes and Kant, a denial of quality in favor of quantity.
In a restricted sense, mechanism is interpretation of the highly complex activities of life as merely the product of the organization and interplay of physico-chemical forces, either known or unknown.
The term is used by Herbart as a synonym for materialism.
New Catholic Dictionary