12 ideas
8226 | A well-posed problem is a problem solved [Bergson, by Deleuze/Guattari] |
Full Idea: Bergson said that a well-posed problem was a problem solved | |
From: report of Henri Bergson (works [1910]) by G Deleuze / F Guattari - What is Philosophy? 1.3 | |
A reaction: This is fairly well in tune with the logical positivist style of philosophising, which tends to ask "what exactly is the question?" rather more than it asks "what is the answer?". I thoroughly approve of both of them (e.g. on free will). |
2661 | Dialectic is speech cast in the form of logical argument [Cicero] |
Full Idea: Dialectic is speech cast in the form of logical argument. | |
From: M. Tullius Cicero (Academica [c.45 BCE], I.viii.32) |
2673 | There cannot be more than one truth [Cicero] |
Full Idea: There cannot be more than one truth. | |
From: M. Tullius Cicero (Academica [c.45 BCE], II.xlviii.147) |
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. |
2669 | Dialectic assumes that all statements are either true or false, but self-referential paradoxes are a big problem [Cicero] |
Full Idea: It is a fundamental principle of dialectic that every statement is either true or false. So is this a true proposition or a false one: "If you say that you are lying and say it truly, you lie"? | |
From: M. Tullius Cicero (Academica [c.45 BCE], II.xxix.95) |
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. |
2664 | If we have complete healthy senses, what more could the gods give us? [Cicero] |
Full Idea: If human nature were interrogated by some god as to whether it was content with its own senses in a sound and undamaged state or demanded something better, I cannot see what more it could ask for. | |
From: M. Tullius Cicero (Academica [c.45 BCE], II.vii.19) |
2665 | How can there be a memory of what is false? [Cicero] |
Full Idea: How can there possibly be a memory of what is false? | |
From: M. Tullius Cicero (Academica [c.45 BCE], II.vii.22) |
20800 | Every true presentation can have a false one of the same quality [Cicero] |
Full Idea: [The sceptical Academics say] what is false cannot be perceived, but every true presentation is such that there can be a false presentation of the same quality. | |
From: M. Tullius Cicero (Academica [c.45 BCE], II.40) | |
A reaction: It was the stoics who focused the discussion on 'presentations'. This claim is purely theoretical; no one has ever experienced a false presentation of talking to a family member that was as vivid as the real thing. |
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). |
2672 | Virtues must be very detached, to avoid being motivated by pleasure [Cicero] |
Full Idea: None of the virtues can exist unless they are disinterested, for virtue driven to duty by pleasure as a sort of pay is not virtue at all but a deceptive sham and pretence of virtue. | |
From: M. Tullius Cicero (Academica [c.45 BCE], II.xlvi.140) |