Full Idea
The empiricist does not say to the metaphysician 'what you say is false', but 'what you say asserts nothing at all!' He does not contradict him, but says 'I don't understand you'.
Gist of Idea
The empiricist says that metaphysics is meaningless, rather than false
Source
Moritz Schlick (Positivism and Realism [1934], p.107), quoted by Jonathan Schaffer - On What Grounds What 1.1
Book Reference
'Metametaphysics', ed/tr. Chalmers/Manley/Wasserman [OUP 2009], p.349
A Reaction
I take metaphysics to be meaningful, but at such a high level of abstraction that it is easy to drift into vague nonsense, and incredibly hard to assess what is meant, and whether it is correct. The truths of metaphysics are not recursive.