Combining Texts

Ideas for 'fragments/reports', 'Rationality in Action' and 'Mental Files'

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

display all the ideas for this combination of texts

---

5 ideas

5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic

3809	If complex logic requires rules, then so does basic logic [Searle]
	Full Idea: If you think you need a rule to infer q from 'p and (if p then q)', then you would also need a rule to infer p from p.
	From: John Searle (Rationality in Action [2001], Ch.1.II)

5. Theory of Logic / B. Logical Consequence / 5. Modus Ponens

8078	Modus ponens is one of five inference rules identified by the Stoics [Chrysippus, by Devlin]
	Full Idea: Modus ponens is just one of the five different inference rules identified by the Stoics.
	From: report of Chrysippus (fragments/reports [c.240 BCE]) by Keith Devlin - Goodbye Descartes Ch.2
	A reaction: Modus ponens strikes me as being more like a definition of implication than a 'rule'. Implication is what gets you from one truth to another. All the implications of a truth must also be true.

5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle

6023	Every proposition is either true or false [Chrysippus, by Cicero]
	Full Idea: We hold fast to the position, defended by Chrysippus, that every proposition is either true or false.
	From: report of Chrysippus (fragments/reports [c.240 BCE]) by M. Tullius Cicero - On Fate ('De fato') 38
	A reaction: I am intrigued to know exactly how you defend this claim. It may depend what you mean by a proposition. A badly expressed proposition may have indeterminate truth, quite apart from the vague, the undecidable etc.

5. Theory of Logic / F. Referring in Logic / 1. Naming / d. Singular terms

16357	Mental files are the counterparts of singular terms [Recanati]
	Full Idea: Mental files are the mental counterparts of singular terms.
	From: François Recanati (Mental Files [2012], 3.3)
	A reaction: A thoroughly satisfactory theory. We can build up a picture of filing merging, duplication, ambiguity, error etc. Eventually neuroscience will map the whole system, and we will have cracked it.

5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic

3810	In real reasoning semantics gives validity, not syntax [Searle]
	Full Idea: In real-life reasoning it is the semantic content that guarantees the validity of the inference, not the syntactical rule.
	From: John Searle (Rationality in Action [2001], Ch.1.II)