8 ideas
| 11211 | If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt] |
| Full Idea: If a designated conclusion follows from the premisses, but the argument involves two howlers which cancel each other out, then the moral is that the path an argument takes from premisses to conclusion does matter to its logical evaluation. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], II) | |
| A reaction: The drift of this is that our view of logic should be a little closer to the reasoning of ordinary language, and we should rely a little less on purely formal accounts. |
| 11210 | Standardly 'and' and 'but' are held to have the same sense by having the same truth table [Rumfitt] |
| Full Idea: If 'and' and 'but' really are alike in sense, in what might that likeness consist? Some philosophers of classical logic will reply that they share a sense by virtue of sharing a truth table. | |
| From: Ian Rumfitt ("Yes" and "No" [2000]) | |
| A reaction: This is the standard view which Rumfitt sets out to challenge. |
| 11212 | The sense of a connective comes from primitively obvious rules of inference [Rumfitt] |
| Full Idea: A connective will possess the sense that it has by virtue of its competent users' finding certain rules of inference involving it to be primitively obvious. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], III) | |
| A reaction: Rumfitt cites Peacocke as endorsing this view, which characterises the logical connectives by their rules of usage rather than by their pure semantic value. |
| 2602 | What experience could prove 'If a=c and b=c then a=b'? [Descartes] |
| Full Idea: Please tell me what the corporeal motion is that is capable of forming some common notion to the effect that 'things which are equal to a third thing are equal to each other'. | |
| From: René Descartes (Comments on a Certain Broadsheet [1644], p.366) |
| 2600 | The mind's innate ideas are part of its capacity for thought [Descartes] |
| Full Idea: I have never written or taken the view that the mind requires innate ideas which are something distinct from its own faculty of thinking. | |
| From: René Descartes (Comments on a Certain Broadsheet [1644], p.365) |
| 2601 | Qualia must be innate, because physical motions do not contain them [Descartes] |
| Full Idea: The ideas of pains, colours, sounds etc. must be all the more innate if, on the occasion of certain corporeal motions, our mind is to be capable of representing them to itself, for there is no similarity between these ideas and the corporeal motions. | |
| From: René Descartes (Comments on a Certain Broadsheet [1644], p.365) | |
| A reaction: Simple and brilliant! We know perfectly well that there is no redness zooming through the air from a tomato (or the air would be pink!). Redness occurs when the light arrives, so we add the redness, so it is innate. |
| 11214 | We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt] |
| Full Idea: The standard view is that affirming not-A is more complex than affirming the atomic sentence A itself, with the latter determining its sense. But we could learn 'not' directly, by learning at once how to either affirm A or reject A. | |
| From: Ian Rumfitt ("Yes" and "No" [2000], IV) | |
| A reaction: [compressed] This seems fairly anti-Fregean in spirit, because it looks at the psychology of how we learn 'not' as a way of clarifying what we mean by it, rather than just looking at its logical behaviour (and thus giving it a secondary role). |
| 21378 | We clearly feel responsible for our deeds, because we are quite certain that we did them [Schopenhauer] |
| Full Idea: Another fact of consciousness ...is the wholly clear and certain feeling of responsibility for what we do, of the accountability of our actions, which rests on the unshakable certainty that we ourselves are the doers of our deeds. | |
| From: Arthur Schopenhauer (On the Freedom of the Will [1841], p.93-4), quoted by Christopher Janaway - Schopenhauer 7 'Freedom' | |
| A reaction: The point is that we have this feeling even if we do not believe in free will. I am struck by the fact that responsibility is very obvious in our own case, even if it is not when we objectively consider other people. Even villains can feel guilty. |