Combining Texts

Ideas for 'works', 'A Note on the entscheidungsproblem' and 'Wittgenstein's 'Tractatus Logico-Philosophicus''

unexpand these ideas     |    start again     |     choose another area for these texts

display all the ideas for this combination of texts

---

1 idea

5. Theory of Logic / K. Features of Logics / 7. Decidability

18758	Validity is provable, but invalidity isn't, because the model is infinite [Church, by McGee]
	Full Idea: Church showed that logic has a proof procedure, but no decision procedure. If an argument is invalid, there is a model with true premises and false conclusion, but the model will typically be infinite, so there is no way to display it concretely.
	From: report of Alonzo Church (A Note on the entscheidungsproblem [1936]) by Vann McGee - Logical Consequence 5