13 ideas
| 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) |
| 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) |
| 12205 | There are two families of modal notions, metaphysical and epistemic, of equal strength [Edgington] |
| Full Idea: In my view, there are two independent families of modal notions, metaphysical and epistemic, neither stronger than the other. | |
| From: Dorothy Edgington (Two Kinds of Possibility [2004], Abs) | |
| A reaction: My immediate reaction is that epistemic necessity is not necessity at all. 'For all I know' 2 plus 2 might really be 95, and squares may also be circular. |
| 12207 | Metaphysical possibility is discovered empirically, and is contrained by nature [Edgington] |
| Full Idea: Metaphysical necessity derives from distinguishing things which can happen and things which can't, in virtue of their nature, which we discover empirically: the metaphysically possible, I claim, is constrained by the laws of nature. | |
| From: Dorothy Edgington (Two Kinds of Possibility [2004], §I) | |
| A reaction: She claims that Kripke is sympathetic to this. Personally I like the idea that natural necessity is metaphysically necessary (see 'Scientific Essentialism'), but the other way round comes as a bit of a surprise. I will think about it. |
| 12206 | Broadly logical necessity (i.e. not necessarily formal logical necessity) is an epistemic notion [Edgington] |
| Full Idea: So-called broadly logical necessity (by which I mean, not necessarily formal logical necessity) is an epistemic notion. | |
| From: Dorothy Edgington (Two Kinds of Possibility [2004], §I) | |
| A reaction: This is controversial, and is criticised by McFetridge and Rumfitt. Fine argues that 'narrow' (formal) logical necessity is metaphysical. Between them they have got rid of logical necessity completely. |
| 12208 | An argument is only valid if it is epistemically (a priori) necessary [Edgington] |
| Full Idea: Validity is governed by epistemic necessity, i.e. an argument is valid if and only if there is an a priori route from premises to conclusion. | |
| From: Dorothy Edgington (Two Kinds of Possibility [2004], §V) | |
| A reaction: Controversial, and criticised by McFetridge and Rumfitt. I don't think I agree with her. I don't see validity as depending on dim little human beings. |
| 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. |
| 7861 | Libet says the processes initiated in the cortex can still be consciously changed [Libet, by Papineau] |
| Full Idea: Libet himself points out that the conscious decisions still have the power to 'endorse' or 'cancel', so to speak, the processes initiated by the earlier cortical activity: no action will result if the action's execution is consciously countermanded. | |
| From: report of Benjamin Libet (Unconscious Cerebral Initiative [1985]) by David Papineau - Thinking about Consciousness 1.4 | |
| A reaction: This is why Libet's findings do not imply 'epiphenomenalism'. It seems that part of a decisive action is non-conscious, undermining the all-or-nothing view of consciousness. Searle tries to smuggle in free will at this point (Idea 3817). |
| 6660 | Libet found conscious choice 0.2 secs before movement, well after unconscious 'readiness potential' [Libet, by Lowe] |
| Full Idea: Libet found that a subject's conscious choice to move was about a fifth of a second before movement, and thus later than the onset of the brain's so-called 'readiness potential', which seems to imply that unconscious processes initiates action. | |
| From: report of Benjamin Libet (Unconscious Cerebral Initiative [1985]) by E.J. Lowe - Introduction to the Philosophy of Mind Ch.9 | |
| A reaction: Of great interest to philosophers! It seems to make conscious choices epiphenomenal. The key move, I think, is to give up the idea of consciousness as being all-or-nothing. My actions are still initiated by 'me', but 'me' shades off into unconsciousness. |
| 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) |