Full Idea
In the beginning Russell's ontology included matter as basic, to be known, however, only by inference from sense-data. By the end he wanted to 'contruct' matter from sense-data.
Gist of Idea
At first matter is basic and known by sense-data; later Russell says matter is constructed
Source
report of Bertrand Russell (The Analysis of Matter [1927]) by Bernard Linsky - Russell's Metaphysical Logic 1
Book Reference
Linsky,Bernard: 'Russell's Metaphysical Logic' [CSLI 1999], p.5
A Reaction
[see also p.133] Russell always seems to have been a robust realist about the external world, but the later view seems a lot less realist than the earlier view.
Related Idea
Idea 21722 Better to construct from what is known, than to infer what is unknown [Russell]