I was finishing reading Aboutness by Yablo, but there is an intuitive definition that I do not get:
He says on page 148 that:
What is this relation of adding falsity, or being additionally false, or being false not just because B is false? I want to say that X adds falsity to B 5 when B&X is false for a reason that does not trade on B being false, as is shown by its being instantiable even when B is true. This is the same as B→¬X being true for a reason that can obtain even when B is true. Reasons like this, that do not trade on B’s falsity, are the kind we above called B-compatible or B-friendly.
Why should it make intuitive appeal that we define the fact that A adds falsity to its consequence B when there is a reason for A to be false even when B is true? I do not get intuitively why this should make sense. Can anyone help me on this?