13 ideas
| 13913 | The four 'perfect syllogisms' are called Barbara, Celarent, Darii and Ferio [Engelbretsen/Sayward] |
| Full Idea: There are four 'perfect syllogisms': Barbara (every M is P, every S is M, so every S is P); Celarent (no M is P, every S is M, so no S is P); Darii (every M is P, some S is M, so some S is P); Ferio (no M is P, some S is M, so some S is not P). | |
| From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8) | |
| A reaction: The four names are mnemonics from medieval universities. |
| 13914 | Syllogistic logic has one rule: what is affirmed/denied of wholes is affirmed/denied of their parts [Engelbretsen/Sayward] |
| Full Idea: It has often been claimed (e.g. by Leibniz) that a single rule governs all syllogistic validity, called 'dictum de omni et null', which says that what is affirmed or denied of any whole is affirmed or denied of any part of that whole. | |
| From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8) | |
| A reaction: This seems to be the rule which is captured by Venn Diagrams. |
| 13915 | Syllogistic can't handle sentences with singular terms, or relational terms, or compound sentences [Engelbretsen/Sayward] |
| Full Idea: Three common kinds of sentence cannot be put into syllogistic ('categorical') form: ones using singular terms ('Mars is red'), ones using relational terms ('every painter owns some brushes'), and compound sentences. | |
| From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8) |
| 13916 | Term logic uses expression letters and brackets, and '-' for negative terms, and '+' for compound terms [Engelbretsen/Sayward] |
| Full Idea: Term logic begins with expressions and two 'term functors'. Any simple letter is a 'term', any term prefixed by a minus ('-') is a 'negative term', and any pair of terms flanking a plus ('+') is a 'compound term'. Parenthese are used for grouping. | |
| From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8) | |
| A reaction: [see Engelbretsen and Sayward for the full formal system] |
| 13850 | In modern logic all formal validity can be characterised syntactically [Engelbretsen/Sayward] |
| Full Idea: One of the key ideas of modern formal logic is that all formally valid inferences can be specified in strictly syntactic terms. | |
| From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], Ch.2) |
| 13849 | Classical logic rests on truth and models, where constructivist logic rests on defence and refutation [Engelbretsen/Sayward] |
| Full Idea: Classical logic rests on the concepts of truth and falsity (and usually makes use of a semantic theory based on models), whereas constructivist logic accounts for inference in terms of defense and refutation. | |
| From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], Intro) | |
| A reaction: My instincts go with the classical view, which is that inferences do not depend on the human capacity to defend them, but sit there awaiting revelation. My view isn't platonist, because I take the inferences to be rooted in the physical world. |
| 13851 | Unlike most other signs, = cannot be eliminated [Engelbretsen/Sayward] |
| Full Idea: Unlike ∨, →, ↔, and ∀, the sign = is not eliminable from a logic. | |
| From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], Ch.3) |
| 13852 | Axioms are ω-incomplete if the instances are all derivable, but the universal quantification isn't [Engelbretsen/Sayward] |
| Full Idea: A set of axioms is said to be ω-incomplete if, for some universal quantification, each of its instances is derivable from those axioms but the quantification is not thus derivable. | |
| From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 7) |
| 7855 | Some suggest that materialism is empty, because 'physical' cannot be properly characterized [Mellor/Crane, by Papineau] |
| Full Idea: It is sometimes contended that the whole idea of materialism is somehow empty, on the grounds that there is no proper way to characterize the 'physical' realm. | |
| From: report of DH Mellor / T Crane (There is no question of physicalism [1990]) by David Papineau - Thinking about Consciousness 1.1 | |
| A reaction: [Papineau also cites Gabriel Segal] I agree with Papineau in rejecting this. Uncertainties about quantum states do not pose a problem, and the position tends to have an implicit dualism buried in it somewhere. |
| 6120 | Causation depends on intrinsic properties [Mellor/Crane] |
| Full Idea: The problem thoughts pose for causation is that causation depends directly only on intrinsic properties, whereas the causal powers of token thoughts depend on their contents, which are not intrinsic. | |
| From: DH Mellor / T Crane (There is no question of physicalism [1990], p.194) | |
| A reaction: This, as we find later in the paper, depends on an externalist account of thoughts. Could a relational property not be causal? Edinburgh's being wetter than London is caused by its being further north? |
| 6121 | There are many psychophysicals laws - about the effects of sweets, colours and soft cushions [Mellor/Crane] |
| Full Idea: There are many psychophysical laws, linking sensations to non-mental features of those who have them; the industries of anaesthetics, scents, narcotics, sweeteners, coloured paints, loudspeakers and soft cushions depend on them. | |
| From: DH Mellor / T Crane (There is no question of physicalism [1990], p.198) | |
| A reaction: It may be expressing it a little strongly to call these 'laws', but they are certainly reliable regularities, and they are probably enough to undermine Davidson's claim that such laws don't exist. |
| 6122 | No defences of physicalism can deprive psychology of the ontological authority of other sciences [Mellor/Crane] |
| Full Idea: Neither laws nor causation nor claims of supervenience (the last refuge of the physicalist) deprive psychology of the ontological authority of non-mental science. | |
| From: DH Mellor / T Crane (There is no question of physicalism [1990], p.203) | |
| A reaction: There is no need to defend the practice of psychologists (or garden designers) from the depradations of bandit physicalists. But what is the ontology of psychology if it isn't dualist or physicalist? |
| 1513 | The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus] |
| Full Idea: The Egyptians were the first to claim that the soul of a human being is immortal, and that each time the body dies the soul enters another creature just as it is being born. | |
| From: Herodotus (The Histories [c.435 BCE], 2.123.2) |