Combining Texts

All the ideas for 'Conditionals', 'A Specimen of Discoveries' and 'An Inquiry into Meaning and Truth'

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22 ideas

2. Reason / A. Nature of Reason / 4. Aims of Reason
5035 The two basics of reasoning are contradiction and sufficient reason [Leibniz]
3. Truth / A. Truth Problems / 7. Falsehood
16477 Asserting not-p is saying p is false [Russell]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / e. Existential quantifier ∃
16484 There are four experiences that lead us to talk of 'some' things [Russell]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
16486 The physical world doesn't need logic, but the mental world does [Russell]
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
2947 Questions wouldn't lead anywhere without the law of excluded middle [Russell]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / e. or
16480 A disjunction expresses indecision [Russell]
16479 'Or' expresses hesitation, in a dog at a crossroads, or birds risking grabbing crumbs [Russell]
16481 'Or' expresses a mental state, not something about the world [Russell]
16487 Maybe the 'or' used to describe mental states is not the 'or' of logic [Russell]
16483 Disjunction may also arise in practice if there is imperfect memory. [Russell]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / c. Grelling's paradox
16475 A 'heterological' predicate can't be predicated of itself; so is 'heterological' heterological? Yes=no! [Russell]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
13768 Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington]
10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional
13770 There are many different conditional mental states, and different conditional speech acts [Edgington]
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
13764 Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington]
13765 'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington]
11. Knowledge Aims / A. Knowledge / 1. Knowledge
16482 All our knowledge (if verbal) is general, because all sentences contain general words [Russell]
11. Knowledge Aims / C. Knowing Reality / 1. Perceptual Realism / a. Naïve realism
4758 Naïve realism leads to physics, but physics then shows that naïve realism is false [Russell]
12. Knowledge Sources / D. Empiricism / 1. Empiricism
16476 For simple words, a single experience can show that they are true [Russell]
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
16485 Perception can't prove universal generalisations, so abandon them, or abandon empiricism? [Russell]
17. Mind and Body / A. Mind-Body Dualism / 5. Parallelism
5038 Assume that mind and body follow their own laws, but God has harmonised them [Leibniz]
20. Action / C. Motives for Action / 3. Acting on Reason / b. Intellectualism
16478 A mother cat is paralysed if equidistant between two needy kittens [Russell]
29. Religion / D. Religious Issues / 3. Problem of Evil / b. Human Evil
5037 God doesn't decide that Adam will sin, but that sinful Adam's existence is to be preferred [Leibniz]