Full Idea
I regard sense-data as not mental, and as being, in fact, part of the actual subject-matter of physics.
Gist of Idea
Sense-data are not mental, but are part of the subject-matter of physics
Source
Bertrand Russell (The Relation of Sense-Data to Physics [1914], §III)
Book Reference
Russell,Bertrand: 'Mysticism and Logic' [Unwin 1989], p.144
A Reaction
Russell had clearly given himself an ontological problem with the introduction of sense-data, and this is his drastic solution. In 1912 his account seems ambiguous between sense-data being mental and being physical.