Full Idea
If you are a phenomenalist about objects, then there is an important sense in which you ought to be a Regularity theorist about what causation is, in such objects.
Gist of Idea
A phenomenalist about objects has to be a regularity theorist about causation
Source
Galen Strawson (The Secret Connexion [1989], App C)
Book Reference
Strawson,Galen: 'The Secret Connexion' [OUP 1992], p.276
A Reaction
Strawson is denying that Hume is a phenomenalist. One might go a little further, and say that a phenomenalist should abandon the idea of causation (as Russell did).