15 ideas
| 20728 | Metaphysics is hopeless with its present epistemology; common-sense realism is needed [Colvin] |
| Full Idea: Despair over metaphysics will not change until it has shaken off the incubus of a perverted epistemology, which has left thought in a hopeless tangle - until common-sense critical realism is made the starting point for investigating reality. | |
| From: Stephen S. Colvin (The Common-Sense View of Reality [1902], p.144) | |
| A reaction: It seems to me that this is what has happened to analytic metaphysics since Kripke. Careful discussions about the nature of an object, or a category, or a property, are relying on unquestioned robust realism. Quite right too. |
| 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) |
| 20726 | We can only distinguish self from non-self if there is an inflexible external reality [Colvin] |
| Full Idea: Were there no inflexible reality outside of the individual, opposing and limiting it, knowledge of the self and the non-self would never develop. | |
| From: Stephen S. Colvin (The Common-Sense View of Reality [1902], p.140) | |
| A reaction: Presumably opponents would have to say that such 'knowledge' is an illusion. This is in no way a conclusive argument, but I approach the problem of realism in quest of the best explanation, and this idea is important evidence. |
| 20727 | Common-sense realism rests on our interests and practical life [Colvin] |
| Full Idea: It is the determination of the external world from the practical standpoint, from the standpoint of interest, that may be defined as the common-sense view of reality. | |
| From: Stephen S. Colvin (The Common-Sense View of Reality [1902], p.141) | |
| A reaction: Probably more appropriately named the 'pragmatic' view of reality. Relying on what is 'practical' seems to offer some objectivity, but relying on 'interest' rather less so. Can I be an anti-realist when life goes badly, and a realist when it goes well? |
| 20729 | Arguments that objects are unknowable or non-existent assume the knower's existence [Colvin] |
| Full Idea: Arguments for the absolute unknowability or non-existence of an external object only works by assuming that another external object, an individual, is known completely in so far as that individual expresses a judgement about an external object. | |
| From: Stephen S. Colvin (The Common-Sense View of Reality [1902], p.145) | |
| A reaction: Anti-realism is a decay that eats into everything. You can't doubt all the externals without doubting all the internals as well. |
| 20730 | If objects are doubted because their appearances change, that presupposes one object [Colvin] |
| Full Idea: If objects are doubted because the same object appears differently at different times and circumstances, in order that this judgement shall have weight it must be assumed that the object under question is the same in its different presentations. | |
| From: Stephen S. Colvin (The Common-Sense View of Reality [1902], p.145) | |
| A reaction: [compressed] Scepticism could eat into the underlying object as well. Is the underlying object a 'substrate'? If so, what's that? Is the object just a bundle of a properties? If so, there is no underlying object. |
| 20731 | The idea that everything is relations is contradictory; relations are part of the concept of things [Colvin] |
| Full Idea: The doctrine [that all we can know is the relations between subject and object] is in its essence self-contradictory, since our very idea of thing implies that it is something in relation either actually or potentially. | |
| From: Stephen S. Colvin (The Common-Sense View of Reality [1902], p.150) | |
| A reaction: Ladyman and Ross try to defend an account of reality based entirely on relations. I'm with Colvin on this one. All accounts of reality based either on pure relations or pure functions have a huge hole in their theory. |
| 3061 | Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius] |
| Full Idea: Anaxarchus said that he was not even sure that he knew nothing. | |
| From: report of Anaxarchus (fragments/reports [c.340 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.10.1 |