| 24138 | Strongly believed a priori is not certain; it may just be a feature of our existence [Nietzsche] |
| Full Idea: What we believe the most, everything a priori, is not for that reason more certain, just because it is so strongly believed. Rather, it is perhaps a consequence of the condition for the existence of our species. | |
| From: Friedrich Nietzsche (Unpublished Notebooks 1884-85 [1884], 25[307]) | |
| A reaction: This is in defiance of Leibniz and Kant. His proposed explanation is not very convincing. Russell agreed with Nietzsche. |
| 23485 | No pictures are true a priori [Wittgenstein] |
| Full Idea: There are no pictures that are true a priori. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.225) | |
| A reaction: This is part of the growing modern doubts about the scope or possibility of a priori knowledge. A 'picture' here is the mental model which is the meaning of a proposition. |
| 9337 | Science is empirical, simple and conservative; any belief can hence be abandoned; so no a priori [Quine, by Horwich] |
| Full Idea: Quine says scientific beliefs follow empirical adequacy, simplicity and conservatism; science and rationality support this view; hence any hypothesis can be abandoned to increase simplicity; so no scientific belief is a priori. | |
| From: report of Willard Quine (Two Dogmas of Empiricism [1953]) by Paul Horwich - Stipulation, Meaning and Apriority §10 | |
| A reaction: [Compressed] I just don't accept this claim. If science wants to drop simple arithmetic or the laws of thought, so much the worse for science - they've obviously taken a wrong turning somewhere. We must try to infer God's logic. |
| 9338 | Quine's objections to a priori knowledge only work in the domain of science [Horwich on Quine] |
| Full Idea: Quine's arguments provide no reason to doubt the existence of a priori knowledge outside the domain of science. | |
| From: comment on Willard Quine (Two Dogmas of Empiricism [1953]) by Paul Horwich - Stipulation, Meaning and Apriority §10 | |
| A reaction: This rather ignores Quine's background view of thoroughgoing physicalism, so that the domain of science is the domain of nature, which is the domain of everything. See his naturalising of epistemology, for example. Maths is part of his science. |
| 9340 | Logic, arithmetic and geometry are revisable and a posteriori; quantum logic could be right [Horwich on Quine] |
| Full Idea: I think logic, arithmetic and geometry are subject to Quine's empirical revisability argument: quantum logic may turn out to be the best overall theory; so these things are justified a posteriori. | |
| From: comment on Willard Quine (Two Dogmas of Empiricism [1953]) by Paul Horwich - Stipulation, Meaning and Apriority §11 | |
| A reaction: Not much of an argument, because 'quantum logic' may also turn out to be a will-o'-the-whisp. Until it is established (which I doubt, because quantum theory is so poorly understood), I think we should be highly suspicious of the Quinean view. |
| 20961 | What is considered a priori changes as language changes [Habermas, by Bowie] |
| Full Idea: Habermas claims that what is regarded as a priori changes with history. This is because the linguistic structures on which judgements depend are themselves part of history, not prior to it. | |
| From: report of Jürgen Habermas (The Theory of Communicative Action [1981]) by Andrew Bowie - Introduction to German Philosophy Conc 'Habermas' | |
| A reaction: This is an interesting style of argument generally only found in continental philosophers, because they see the problem as historical rather than timeless. Compare Idea 20595, which sees analyticity historically. |
| 18272 | Platonism defines the a priori in a way that makes it unknowable [Coffa] |
| Full Idea: The trouble with Platonism had always been its inability to define a priori knowledge in a way that made it possible for human beings to have it. | |
| From: J. Alberto Coffa (The Semantic Tradition from Kant to Carnap [1991], 7 'What') | |
| A reaction: This is the famous argument of Benacerraf 1973. |
| 9356 | The idea of the a priori is so obscure that it won't explain anything [Devitt] |
| Full Idea: The whole idea of the a priori is too obscure for it to feature in a good explanation of our knowledge of anything. | |
| From: Michael Devitt (There is no a Priori [2005], §3) | |
| A reaction: I never like this style of argument. It would be nice if all the components of all our our explanations were crystal clear. Total clarity about anything is probably a hopeless dream, and we may have to settle for murky corners in all explanations. |
| 19564 | Some knowledge must be empirical; naturalism implies that all knowledge is like that [Devitt] |
| Full Idea: It is overwhelmingly plausible that some knowledge is empirical. The attractive thesis of naturalism is that all knowledge is; there is only one way of knowing. | |
| From: Michael Devitt (There is No A Priori (and reply) [2005], 1) | |
| A reaction: How many ways for us to know seems to depend on what faculties we have. We lump our senses together under a single heading. The arrival of data is not the same as the arrival of knowledge. I'm unconvinced that naturalists like me must accept this. |
| 13476 | The failure of key assumptions in geometry, mereology and set theory throw doubt on the a priori [Hart,WD] |
| Full Idea: In the case of the parallels postulate, Euclid's fifth axiom (the whole is greater than the part), and comprehension, saying was believing for a while, but what was said was false. This should make a shrewd philosopher sceptical about a priori knowledge. | |
| From: William D. Hart (The Evolution of Logic [2010], 2) | |
| A reaction: Euclid's fifth is challenged by infinite numbers, and comprehension is challenged by Russell's paradox. I can't see a defender of the a priori being greatly worried about these cases. No one ever said we would be right - in doing arithmetic, for example. |
| 9384 | We may have strong a priori beliefs which we pragmatically drop from our best theory [Boghossian] |
| Full Idea: It is consistent with a belief's being a priori in the strong sense that we should have pragmatic reasons for dropping it from our best overall theory. | |
| From: Paul Boghossian (Analyticity Reconsidered [1996], n 6) | |
| A reaction: Does 'dropping it' from the theory mean just ignoring it, or actually denying it? C.I. Lewis is the ancestor of this view. Could it be our 'best' theory, while conflicting with beliefs that were strongly a priori? Pragmatism can embrace falsehoods. |