Full Idea
The truth trees method for establishing the validity of arguments and formulas is easy to use, and has the advantage that if an argument or formula is not valid, then a counter-example can be retrieved from the tree.
Gist of Idea
If an argument is invalid, a truth tree will indicate a counter-example
Source
Rod Girle (Modal Logics and Philosophy [2000], 1.4)
Book Reference
Girle,Rod: 'Modal Logics and Philosophy' [Acumen 2000], p.8
Related Idea
Idea 13613 A completed open branch gives an interpretation which verifies those formulae [Bostock]