more on this theme | more from this thinker | more from this text
Full Idea
Hume's second definition of cause (one object always 'conveys the thought' of another) implies that it is inconceivable that there should be causal laws which have never yet been thought of, and this is not so.
Gist of Idea
Hume's definition of cause as constantly joined thoughts can't cover undiscovered laws
Source
comment on David Hume (Enquiry Conc Human Understanding [1748], VII.II.60) by A.J. Ayer - Language,Truth and Logic Ch.2
Book Ref
Ayer,A.J.: 'Language, Truth and Logic' [Penguin 1974], p.74
A Reaction
This appears to be a good criticism of Hume, but also a bit of a problem for a strong empiricist like Ayer. There may also be causal laws which we cannot discover, but logical positivism will not allow me to speculate about that.