7 ideas
12430 | Classical logic is our preconditions for assessing empirical evidence [Kitcher] |
Full Idea: In my terminology, classical logic (or at least, its most central tenets) consists of propositional preconditions for our assessing empirical evidence in the way we do. | |
From: Philip Kitcher (A Priori Knowledge Revisited [2000], §VII) | |
A reaction: I like an even stronger version of this - that classical logic arises out of our experiences of things, and so we are just assessing empirical evidence in terms of other (generalised) empirical evidence. Logic results from induction. Very unfashionable. |
12431 | I believe classical logic because I was taught it and use it, but it could be undermined [Kitcher] |
Full Idea: I believe the laws of classical logic, in part because I was taught them, and in part because I think I see how those laws are used in assessing evidence. But my belief could easily be undermined by experience. | |
From: Philip Kitcher (A Priori Knowledge Revisited [2000], §VII) | |
A reaction: Quine has one genuine follower! The trouble is his first sentence would fit witch-doctoring just as well. Kitcher went to Cambridge; I hope he doesn't just believe things because he was taught them, or because he 'sees how they are used'! |
12428 | Many necessities are inexpressible, and unknowable a priori [Kitcher] |
Full Idea: There are plenty of necessary truths that we are unable to express, let alone know a priori. | |
From: Philip Kitcher (A Priori Knowledge Revisited [2000], §II) | |
A reaction: This certainly seems to put paid to any simplistic idea that the a priori and the necessary are totally coextensive. We might, I suppose, claim that all necessities are a priori for the Archangel Gabriel (or even a very bright cherub). Cf. Idea 12429. |
12429 | Knowing our own existence is a priori, but not necessary [Kitcher] |
Full Idea: What is known a priori may not be necessary, if we know a priori that we ourselves exist and are actual. | |
From: Philip Kitcher (A Priori Knowledge Revisited [2000], §II) | |
A reaction: Compare Idea 12428, which challenges the inverse of this relationship. This one looks equally convincing, and Kripke adds other examples of contingent a priori truths, such as those referring to the metre rule in Paris. |
6668 | If the present does not exist, then consciousness must be memory of the immediate past [Marshall] |
Full Idea: Given the paradoxical nature of the 'present' moment, maybe we should understand ALL consciousness as memory, with the split second of the 'specious present' being very vivid and very brief memory, with the rest of the mind remembering in lower degrees. | |
From: David Marshall (talk [2004]), quoted by PG - Db (ideas) | |
A reaction: This strikes me as a highly plausible, and very illuminating remark. For the time paradox, see Ideas 1904 and 5102. Anyone researching consciousness in the brain should think about this, because it will just be a special sort of memory neurons. |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |