| 5403 | If, as Kant says, arithmetic and logic are contributed by us, they could change if we did [Russell on Kant] |
| Full Idea: The main objection to Kant's philosophy is that to say that logic and arithmetic are contributed by us does not account for its certainty; if Kant is right, then tomorrow our nature could so change as to make two and two become five. | |
| From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Bertrand Russell - Problems of Philosophy Ch.8 | |
| A reaction: One would expect a realist like Russell to have fairly fundamental objections to the implied anti-realism (and conventionalism) of Kant. The same comment could be made about Kant's view of space, time and causation. |
| 4539 | The forms of 'knowledge' about logic which precede experience are actually regulations of belief [Nietzsche] |
| Full Idea: The basic laws of logic (identity and contradiction) are said to be forms of pure knowledge because they precede experience. But these are not forms of knowledge at all! They are regulative articles of belief. | |
| From: Friedrich Nietzsche (The Will to Power (notebooks) [1888], §530) | |
| A reaction: This is a standard objection to foundationalism - that the basic beliefs (of reason, or raw experience) are not actually knowledge. We can all speculate about their origin and basis. Personally I think 'truth' must be somewhere in the explanation. |
| 9365 | We can maintain a priori principles come what may, but we can also change them [Lewis,CI] |
| Full Idea: The a priori contains principles which can be maintained in the face of all experience, representing the initiative of the mind. But they are subject to alteration on pragmatic grounds, if expanding experience shows their intellectual infelicity. | |
| From: C.I. Lewis (A Pragmatic Conception of the A Priori [1923], p.373) | |
| A reaction: [compressed] This simply IS Quine's famous 'web of belief' picture, showing how firmly Quine is in the pragmatist tradition. Lewis treats a priori principles as a pragmatic toolkit, which can be refined to be more effective. Not implausible... |
| 5197 | By changing definitions we could make 'a thing can't be in two places at once' a contradiction [Ayer] |
| Full Idea: The proposition that 'a material thing cannot be in two places at once' is not empirical at all, but linguistic; ..we could so alter our definitions that the proposition came to express a self-contradiction instead of a necessary truth. | |
| From: A.J. Ayer (Language,Truth and Logic [1936], Ch.2) | |
| A reaction: This seems a striking anticipation of Quine's famous challenge to the analytic/synthetic distinction. |
| 9005 | Examination of convention in the a priori begins to blur the distinction with empirical knowledge [Quine] |
| Full Idea: In trying to make sense of the role of convention in a priori knowledge, the very distinction between a priori and empirical begins to waver and dissolve. | |
| From: Willard Quine (Carnap and Logical Truth [1954], VI) | |
| A reaction: This is the next stage in the argument after Wittgenstein presents the apriori as nothing more than what arises from truth tables. The rationalists react by taking us back to the original 'natural light of reason' view. Then we go round again... |
| 9164 | We treat basic rules as if they were indefeasible and a priori, with no interest in counter-evidence [Field,H] |
| Full Idea: I argue not that our most basic rules are a priori or empirically indefeasible, but that we treat them as empirically defeasible and indeed a priori; we don't regard anything as evidence against them. | |
| From: Hartry Field (Apriority as an Evaluative Notion [2000], 4) | |
| A reaction: This is the fictionalist view of a priori knowledge (and of most other things, such as mathematics). I can't agree. Most people treat heaps of a posteriori truths (like the sun rising) as a priori. 'Mass involves energy' is indefeasible a posteriori. |