10 ideas
| 8083 | Boole applied normal algebra to logic, aiming at an algebra of thought [Boole, by Devlin] |
| Full Idea: Boole proposed to use the entire apparatus of a school algebra class, with operations such as addition and multiplication, methods to solve equations, and the like, to produce an algebra of thought. | |
| From: report of George Boole (The Laws of Thought [1854]) by Keith Devlin - Goodbye Descartes Ch.3 | |
| A reaction: The Stoics didn’t use any algebraic notation for their study of propositions, so Boole's idea launched full blown propositional logic, and the rest of modern logic followed. Nice one. |
| 7727 | Boole's notation can represent syllogisms and propositional arguments, but not both at once [Boole, by Weiner] |
| Full Idea: Boole introduced a new symbolic notation in which it was possible to represent both syllogisms and propositional arguments, ...but not both at once. | |
| From: report of George Boole (The Laws of Thought [1854], Ch.3) by Joan Weiner - Frege | |
| A reaction: How important is the development of symbolic notations for the advancement of civilisations? Is there a perfect notation, as used in logical heaven? |
| 8686 | Boole made logic more mathematical, with algebra, quantifiers and probability [Boole, by Friend] |
| Full Idea: Boole (followed by Frege) began to turn logic from a branch of philosophy into a branch of mathematics. He brought an algebraic approach to propositions, and introduced the notion of a quantifier and a type of probabilistic reasoning. | |
| From: report of George Boole (The Laws of Thought [1854], 3.2) by Michèle Friend - Introducing the Philosophy of Mathematics | |
| A reaction: The result was that logic not only became more mathematical, but also more specialised. We now have two types of philosopher, those steeped in mathematical logic and the rest. They don't always sing from the same songsheet. |
| 22277 | Boole's method was axiomatic, achieving economy, plus multiple interpretations [Boole, by Potter] |
| Full Idea: Boole's work was an early example of the axiomatic method, whereby intellectual economy is achieved by studying a set of axioms in which the primitive terms have multiple interpretations. | |
| From: report of George Boole (The Laws of Thought [1854]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 02 'Boole' | |
| A reaction: Unclear about this. I suppose the axioms are just syntactic, and a range of semantic interpretations can be applied. Are De Morgan's Laws interpretations, or implications of the syntactic axioms? The latter, I think. |
| 8808 | Involuntary beliefs can still be evaluated [Feldman/Conee] |
| Full Idea: Examples confirm that beliefs may be both involuntary and subject to epistemic evaluation. | |
| From: R Feldman / E Conee (Evidentialism [1985], II) | |
| A reaction: This is an extremely important point, which summarises the situation with beliefs that arise from (apparent) immediate perception. A belief cannot possibly be knowledge if it has been triggered, but no effort was made to evaluate it. |
| 8807 | Evidentialism is the view that justification is determined by the quality of the evidence [Feldman/Conee] |
| Full Idea: What we call 'evidentialism' is the view that the epistemic justification of a belief is determined by the quality of the believer's evidence for the belief. | |
| From: R Feldman / E Conee (Evidentialism [1985], I) | |
| A reaction: The immediate question is whether the believer knows the quality of their evidence. A detective might not recognise the crucial clue (like the dog not barking). The definition of 'quality' had better not turn out to be circular. Forgotten evidence? |
| 8809 | Beliefs should fit evidence, and if you ought to believe it, then you are justified [Feldman/Conee] |
| Full Idea: One epistemically ought to have the doxastic attitudes that fit one's evidence. Being epistemically obligatory is equivalent to being epistemically justified. | |
| From: R Feldman / E Conee (Evidentialism [1985], III) | |
| A reaction: It is normal for someone to refuse to accept something, when another person believes the evidence is overwhelming. Evaluation of evidence must include an assessment of what other evidence might turn up. |
| 8810 | If someone rejects good criticism through arrogance, that is irrelevant to whether they have knowledge [Feldman/Conee] |
| Full Idea: If an arrogant young physicist refuses to recognise valid criticisms from a senior colleague, his or her character has nothing to do with the epistemic status of their belief in the theory. | |
| From: R Feldman / E Conee (Evidentialism [1985], III) | |
| A reaction: This rejects the idea that epistemic justification is essentially a matter of virtues and vices of character. That view is a version of reliabilism, and hence of externalism. I agree with the criticism, but epistemic virtues are still significant. |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
| From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
| A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
| From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
| A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |