3 ideas
| 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 |
| 18033 | The meaning of a representation is its role in thought, perception or decisions [Block] |
| Full Idea: According to conceptual role semantics, the meaning of a representation is the role of that representation in the cognitive life of the agent, for example, in perception, thought and decision-making. | |
| From: Ned Block (Semantics, Conceptual Role [1998]) | |
| A reaction: I never believe theories of this kind, because I always find myself asking 'what is the nature of this representation which enables it to play this role?'. |
| 7453 | Galen's medicine followed the mean; each illness was balanced by opposite treatment [Galen, by Hacking] |
| Full Idea: Galen ran medicine on the principle of the mean; afflictions must be treated by contraries; hot diseases deserve cold medicine and moist illnesses want drying agents. (Paracelsus rebelled, treating through similarity). | |
| From: report of Galen (On Medical Experience [c.169]) by Ian Hacking - The Emergence of Probability Ch.5 | |
| A reaction: This must be inherited from Aristotle, with the aim of virtue for the body, as Aristotle wanted virtue for the psuché. In some areas Galen is probably right, that natural balance is the aim, as in bodily temperature control. |