Full Idea
Serious metaphysics is committed to views about which sentences entail which other sentences.
Clarification
'Entailment' is logical implication
Gist of Idea
Serious metaphysics cares about entailment between sentences
Source
Frank Jackson (From Metaphysics to Ethics [1998], Ch.1)
Book Reference
Jackson,Frank: 'From Metaphysics to Ethics' [OUP 2000], p.26
A Reaction
This does not say that metaphysics is only about entailment, or (even worse) only about sentences. Put another way: if we wish to be wise, we must study the implications of our beliefs. Yes.