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'! |
| 21710 | We know a universal in 'yellow differs from blue' or 'yellow resembles blue less than green does' [Russell] |
| Full Idea: We are aware of the universal 'yellow'; this universal is the subject in such judgements as 'yellow differs from blue' or 'yellow resembles blue less than green does'. | |
| From: Bertrand Russell (Knowledge by Acquaintance and Description-1 [1911], 154), quoted by Bernard Linsky - Russell's Metaphysical Logic 2.3 | |
| A reaction: This still seems one of the strongest examples in support of universals. You could hardly be talking about yellow tropes in such instances (even if the world does contain yellow tropes). |
| 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. |
| 8854 | My 'acquaintance' with sense-data is nothing like my knowing New York [Williams,M on Russell] |
| Full Idea: My 'acquaintance' with sense-data is nothing like my knowing New York. | |
| From: comment on Bertrand Russell (Knowledge by Acquaintance and Description-1 [1911]) by Michael Williams - Without Immediate Justification §4 | |
| A reaction: This pinpoints a nice difficulty for Russell. Williams may misrepresent Russell's account of acquaintance, but that is probably because Russell is unclear, or uncertain. The problem is when Russell claims that his acquaintance gives knowledge. |
| 5467 | Euler said nature is instrinsically passive, and minds cause change [Euler, by Ellis] |
| Full Idea: Euler thought the powers necessary for the maintenance of the changing universe would turn out to be just the passive ones of inertia and impenetrability. There are no active powers, he urged, other than those of God and living beings. | |
| From: report of Leonhard Euler (Letters to a German Princess [1765]) by Brian Ellis - The Philosophy of Nature: new essentialism Ch.4 | |
| A reaction: Very significant, I think, for revealing the religious framework behind early theories of natural laws. If there is nothing external to impose powers and movements on nature, the source must be sought within - hence essentialism. |