Full Idea
Our experiences are logically independent, but they may be factually connected. What unites them is that either they are experienced together, or (if at separate times) they are separated by a stream of experience which is felt to be continuous.
Gist of Idea
Experiences are logically separate, but factually linked by simultaneity or a feeling of continuousness
Source
comment on David Hume (Treatise of Human Nature, + Appendix [1740], Bk 3 App.) by A.J. Ayer - The Central Questions of Philosophy §VI.A
Book Reference
Ayer,A.J.: 'The Central Questions of Philosophy' [Penguin 1976], p.115
A Reaction
A strict empiricist cannot deny that the feeling of continuity could be false, though that invites the Cartesian question of what exactly is experiencing the delusion. Hume denies that we experience any link between simultaneous experiences.