display all the ideas for this combination of philosophers
1 idea
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 |