Full Idea
The utility of [truth-functional conditionals] is that it puts us in possession of a rule...[namely] The hypothetical proposition may be ...falsified by a single state of things, but only by one in which A [antecedent] is true and B [consequent] is false.
Gist of Idea
Truth-functional conditionals have a simple falsification, when A is true and B is false
Source
Charles Sanders Peirce (On the Algebra of Logic [1895], p.218), quoted by Stephen Mumford - Dispositions
Book Reference
Mumford,Stephen: 'Dispositions' [OUP 1998], p.45
A Reaction
Personally I am rather more interested in verifying conditionals than in falsifying them. I certainly don't accept them until they are falsified, unless they have massive support from surrounding facts.