EXTERNALISM

Ex‐ter″nal‐ism (?) n. 1. 1. The quality of being manifest to the senses; external acts or appearances; regard for externals.
This externalism gave Catholicism a great advantage on all sides. E. Eggleston. 2. 2. (Metaph.) That philosophy or doctrine which recognizes or deals only with externals, or objects of sense perception; positivism; phenomenalism.