16 ideas
| 10688 | 'Equivocation' is when terms do not mean the same thing in premises and conclusion [Beall/Restall] |
| Full Idea: 'Equivocation' is when the terms do not mean the same thing in the premises and in the conclusion. | |
| From: JC Beall / G Restall (Logical Consequence [2005], Intro) |
| 10690 | Formal logic is invariant under permutations, or devoid of content, or gives the norms for thought [Beall/Restall] |
| Full Idea: Logic is purely formal either when it is invariant under permutation of object (Tarski), or when it has totally abstracted away from all contents, or it is the constitutive norms for thought. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 2) | |
| A reaction: [compressed] The third account sounds rather woolly, and the second one sounds like a tricky operation, but the first one sounds clear and decisive, so I vote for Tarski. |
| 10691 | Logical consequence needs either proofs, or absence of counterexamples [Beall/Restall] |
| Full Idea: Technical work on logical consequence has either focused on proofs, where validity is the existence of a proof of the conclusions from the premises, or on models, which focus on the absence of counterexamples. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 3) |
| 10695 | Logical consequence is either necessary truth preservation, or preservation based on interpretation [Beall/Restall] |
| Full Idea: Two different views of logical consequence are necessary truth-preservation (based on modelling possible worlds; favoured by Realists), or truth-preservation based on the meanings of the logical vocabulary (differing in various models; for Anti-Realists). | |
| From: JC Beall / G Restall (Logical Consequence [2005], 2) | |
| A reaction: Thus Dummett prefers the second view, because the law of excluded middle is optional. My instincts are with the first one. |
| 10689 | A step is a 'material consequence' if we need contents as well as form [Beall/Restall] |
| Full Idea: A logical step is a 'material consequence' and not a formal one, if we need the contents as well as the structure or form. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 2) |
| 10696 | A 'logical truth' (or 'tautology', or 'theorem') follows from empty premises [Beall/Restall] |
| Full Idea: If a conclusion follows from an empty collection of premises, it is true by logic alone, and is a 'logical truth' (sometimes a 'tautology'), or, in the proof-centred approach, 'theorems'. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 4) | |
| A reaction: These truths are written as following from the empty set Φ. They are just implications derived from the axioms and the rules. |
| 10693 | Models are mathematical structures which interpret the non-logical primitives [Beall/Restall] |
| Full Idea: Models are abstract mathematical structures that provide possible interpretations for each of the non-logical primitives in a formal language. | |
| From: JC Beall / G Restall (Logical Consequence [2005], 3) |
| 10692 | Hilbert proofs have simple rules and complex axioms, and natural deduction is the opposite [Beall/Restall] |
| Full Idea: There are many proof-systems, the main being Hilbert proofs (with simple rules and complex axioms), or natural deduction systems (with few axioms and many rules, and the rules constitute the meaning of the connectives). | |
| From: JC Beall / G Restall (Logical Consequence [2005], 3) |
| 12580 | Experiences have no conceptual content [Evans, by Greco] |
| Full Idea: In Evans's work experiences are conceived of as not having a conceptual content at all. | |
| From: report of Gareth Evans (The Varieties of Reference [1980]) by John Greco - Justification is not Internal | |
| A reaction: I presume it is this view which provoked McDowell's contrary view in 'Mind and World'. I say this is a job for neuroscience, and I struggle to see what philosophical questions hang on the outcome. I think I side with Evans. |
| 7643 | We have far fewer colour concepts than we have discriminations of colour [Evans] |
| Full Idea: Do we really understand the proposal that we have as many colour concepts as there are shades colour that we can sensibly discriminate? | |
| From: Gareth Evans (The Varieties of Reference [1980], 7.5) | |
| A reaction: This is the argument (rejected by McDowell) that experience cannot be conceptual because experience is too rich. We should not confuse lack of concepts with lack of words. I may have a concept of a colour between two shades, but no word for it. |
| 7880 | If a blind persons suddenly sees a kestrel, that doesn't make visual and theoretical kestrels different [Papineau on Jackson] |
| Full Idea: An ornithological Mary might know everything theoretical about kestrels, but be blind from birth, then have her sight restored. She now knows "That bird eats mice", so visual kestrels must be ontologically distinct from theoretical ones. | |
| From: comment on Frank Jackson (Epiphenomenal Qualia [1982]) by David Papineau - Thinking about Consciousness 6.3 | |
| A reaction: A nice reductio, and I think this pinpoints best what is wrong with the knowledge argument. Knowledge, and the means of acquiring it, are two distinct things. When I see x, I don't acquire knowledge of x, AND knowledge of my seeing x. |
| 7378 | No one bothers to imagine what it would really be like to have ALL the physical information [Dennett on Jackson] |
| Full Idea: That Mary "has all the physical information" is not readily imaginable, so no one bothers. They just imagine she knows lots and lots - perhaps everything known today - but that is just a drop in the bucket. | |
| From: comment on Frank Jackson (Epiphenomenal Qualia [1982]) by Daniel C. Dennett - Consciousness Explained 12.5 | |
| A reaction: I certainly don't see how we can rule out a priori the possibility that someone who really had all the physical knowledge might be able to infer the phenomenal properties of colour. |
| 7377 | Mary learns when she sees colour, so her complete physical information had missed something [Jackson] |
| Full Idea: It seems obvious that Mary will learn something about the world when she is released from her black-and-white room; but then it is inescapable that her previous knowledge was incomplete; she had all the physical information, so there is more to have. | |
| From: Frank Jackson (Epiphenomenal Qualia [1982], §1) | |
| A reaction: This is Jackson's famous 'knowledge argument', which seems to me misconceived. Since I don't think phenomenal colours are properties of objects (Idea 5456), Mary learns more about herself, and about her means of acquiring knowledge. |
| 23794 | Some representational states, like perception, may be nonconceptual [Evans, by Schulte] |
| Full Idea: Evans introduced the idea that there are some representational states, for example perceptual experiences, which have content that is nonconceptual. | |
| From: report of Gareth Evans (The Varieties of Reference [1980]) by Peter Schulte - Mental Content 3.4 | |
| A reaction: McDowell famously disagree, and whether all experience is inherently conceptualised is a main debate from that period. Hard to see how it could be settled, but I incline to McDowell, because minimal perception hardly counts as 'experience'. |
| 16366 | The Generality Constraint says if you can think a predicate you can apply it to anything [Evans] |
| Full Idea: If a subject can be credited with the thought that a is F, then he must have the conceptual resources for entertaining the thought that a is G, for every property of being G of which he has conception. This condition I call the 'Generality Constraint'. | |
| From: Gareth Evans (The Varieties of Reference [1980], p.104), quoted by François Recanati - Mental Files 5.3 | |
| A reaction: Recanati endorses the Constraint in his account of mental files. Apparently if I can entertain the thought of a circle being round, I can also entertain the thought of it being square, so I am not too sure about this one. |
| 12575 | Concepts have a 'Generality Constraint', that we must know how predicates apply to them [Evans, by Peacocke] |
| Full Idea: Evans's 'Generality Constraint' says that if a thinker is capable of attitudes to the content Fa and possesses the singular concept b, then he is capable of having attitudes to the content Fb. | |
| From: report of Gareth Evans (The Varieties of Reference [1980], 4.3) by Christopher Peacocke - A Study of Concepts 1.1 | |
| A reaction: So having an attitude becomes the test of whether one possesses a concept. I suppose if one says 'You know you've got a concept when you are capable of thinking about it', that is much the same thing. Sounds fine. |