| 13251 | Each person is free to build their own logic, just by specifying a syntax [Carnap] |
| Full Idea: In logic, there are no morals. Everyone is at liberty to build his own logic, i.e. his own form of language. All that is required is that he must state his methods clearly, and give syntactical rules instead of philosophical arguments. | |
| From: Rudolph Carnap (The Logical Syntax of Language [1934], §17), quoted by JC Beall / G Restall - Logical Pluralism 7.3 | |
| A reaction: This is understandable, but strikes me as close to daft relativism. If I specify a silly logic, I presume its silliness will be obvious. By what criteria? I say the world dictates the true logic, but this is a minority view. |
| 18709 | Laws of logic are like laws of chess - if you change them, it's just a different game [Wittgenstein] |
| Full Idea: I might as well question the laws of logic as the laws of chess. If I change the rules it is a different game and there is an end of it. | |
| From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], A XI.3) | |
| A reaction: No, that isn't the end of it, because there are meta-criteria for preferring one game to another. Why don't we just give up classical logic? It would be such fun to have a wild wacky logic. We can start with 'tonk'. |
| 12394 | If the result is bad, we change the rule; if we like the rule, we reject the result [Goodman] |
| Full Idea: A rule is amended if it yields an inference we are unwilling to accept; an inference is rejected if it violates a rule we are unwilling to amend. | |
| From: Nelson Goodman (Fact, Fiction and Forecast (4th ed) [1954], p.64) | |
| A reaction: This is clearly in tune with Quine's assertion that logic is potentially revisable, and the idea is pragmatist in spirit. It is hard to deny that intuitions about what makes a good argument control our logic. I say the world controls our intuitions. |
| 20296 | Logic needs general conventions, but that needs logic to apply them to individual cases [Quine, by Rey] |
| Full Idea: Quine argues that logic could not be established by conventions, since the logical truths, being infinite in number, must be given by general conventions rather than singly; and logic is needed in the meta-theory, to apply to individual cases. | |
| From: report of Willard Quine (Truth by Convention [1935]) by Georges Rey - The Analytic/Synthetic Distinction 3.4 | |
| A reaction: A helpful insight into Quine's claim. If only someone would print these one sentence summaries at the top of classic papers, we would all get far more out of them at first reading. Assuming Rey is right! |
| 8998 | Claims that logic and mathematics are conventional are either empty, uninteresting, or false [Quine] |
| Full Idea: If logic and mathematics being true by convention says the primitives can be conventionally described, that works for anything, and is empty; if the conventions are only for those fields, that's uninteresting; if a general practice, that is false. | |
| From: Willard Quine (Truth by Convention [1935], p.102) | |
| A reaction: This is Quine's famous denial of the traditional platonist view, and the new Wittgensteinian conventional view, preparing the ground for a more naturalistic and empirical view. I feel more sympathy with Quine than with the other two. |
| 8999 | Logic isn't conventional, because logic is needed to infer logic from conventions [Quine] |
| Full Idea: If logic is to proceed mediately from conventions, logic is needed for inferring logic from the conventions. Conventions for adopting logical primitives can only be communicated by free use of those very idioms. | |
| From: Willard Quine (Truth by Convention [1935], p.104) | |
| A reaction: A common pattern of modern argument, which always seems to imply that nothing can ever get off the ground. I suspect that there are far more benign circles in the world of thought than most philosophers imagine. |
| 9000 | If a convention cannot be communicated until after its adoption, what is its role? [Quine] |
| Full Idea: When a convention is incapable of being communicated until after its adoption, its role is not clear. | |
| From: Willard Quine (Truth by Convention [1935], p.106) | |
| A reaction: Quine is discussing the basis of logic, but the point applies to morality - that if there is said to be a convention at work, the concepts of morality must already exist to get the conventional framework off the ground. What is it that comes first? |
| 19289 | Maybe conventionalism applies to meaning, but not to the truth of propositions expressed [Hale] |
| Full Idea: An old objection to conventionalism claims that it confuses sentences with propositions, confusing what makes sentences mean what they do with what makes them (as propositions) true. | |
| From: Bob Hale (Necessary Beings [2013], 05.2) | |
| A reaction: The conventions would presumably apply to the sentences, but not to the propositions. Since I think that focusing on propositions solves a lot of misunderstandings in modern philosophy, I like the sound of this. |