15 ideas
| 15527 | Defining terms either enables elimination, or shows that they don't require elimination [Lewis] |
| Full Idea: To define theoretical terms might be to show how to do without them, but it is better to say that it shows there is no good reason to want to do without them. | |
| From: David Lewis (How to Define Theoretical Terms [1970], Intro) |
| 10993 | Ramsey's Test: believe the consequent if you believe the antecedent [Ramsey, by Read] |
| Full Idea: Ramsey's Test for conditionals is that a conditional should be believed if a belief in its antecedent would commit one to believing its consequent. | |
| From: report of Frank P. Ramsey (Law and Causality [1928]) by Stephen Read - Thinking About Logic Ch.3 | |
| A reaction: A rather pragmatic approach to conditionals |
| 14279 | Asking 'If p, will q?' when p is uncertain, then first add p hypothetically to your knowledge [Ramsey] |
| Full Idea: If two people are arguing 'If p, will q?' and are both in doubt as to p, they are adding p hypothetically to their stock of knowledge, and arguing on that basis about q; ...they are fixing their degrees of belief in q given p. | |
| From: Frank P. Ramsey (Law and Causality [1928], B 155 n) | |
| A reaction: This has become famous as the 'Ramsey Test'. Bennett emphasises that he is not saying that you should actually believe p - you are just trying it for size. The presupposition approach to conditionals seems attractive. Edgington likes 'degrees'. |
| 15530 | A logically determinate name names the same thing in every possible world [Lewis] |
| Full Idea: A logically determinate name is one which names the same thing in every possible world. | |
| From: David Lewis (How to Define Theoretical Terms [1970], III) | |
| A reaction: This appears to be rigid designation, before Kripke introduced the new word. |
| 19553 | Commitment to 'I have a hand' only makes sense in a context where it has been doubted [Hawthorne] |
| Full Idea: If I utter 'I know I have a hand' then I can only be reckoned a cooperative conversant by my interlocutors on the assumption that there was a real question as to whether I have a hand. | |
| From: John Hawthorne (The Case for Closure [2005], 2) | |
| A reaction: This seems to point to the contextualist approach to global scepticism, which concerns whether we are setting the bar high or low for 'knowledge'. |
| 19551 | How can we know the heavyweight implications of normal knowledge? Must we distort 'knowledge'? [Hawthorne] |
| Full Idea: Those who deny skepticism but accept closure will have to explain how we know the various 'heavyweight' skeptical hypotheses to be false. Do we then twist the concept of knowledge to fit the twin desiderata of closue and anti-skepticism? | |
| From: John Hawthorne (The Case for Closure [2005], Intro) | |
| A reaction: [He is giving Dretske's view; Dretske says we do twist knowledge] Thus if I remember yesterday, that has the heavyweight implication that the past is real. Hawthorne nicely summarises why closure produces a philosophical problem. |
| 19552 | We wouldn't know the logical implications of our knowledge if small risks added up to big risks [Hawthorne] |
| Full Idea: Maybe one cannot know the logical consequences of the proposition that one knows, on account of the fact that small risks add up to big risks. | |
| From: John Hawthorne (The Case for Closure [2005], 1) | |
| A reaction: The idea of closure is that the new knowledge has the certainty of logic, and each step is accepted. An array of receding propositions can lose reliability, but that shouldn't apply to logic implications. Assuming monotonic logic, of course. |
| 19554 | Denying closure is denying we know P when we know P and Q, which is absurd in simple cases [Hawthorne] |
| Full Idea: How could we know that P and Q but not be in a position to know that P (as deniers of closure must say)? If my glass is full of wine, we know 'g is full of wine, and not full of non-wine'. How can we deny that we know it is not full of non-wine? | |
| From: John Hawthorne (The Case for Closure [2005], 2) | |
| A reaction: Hawthorne merely raises this doubt. Dretske is concerned with heavyweight implications, but how do you accept lightweight implications like this one, and then suddenly reject them when they become too heavy? [see p.49] |
| 15528 | A Ramsey sentence just asserts that a theory can be realised, without saying by what [Lewis] |
| Full Idea: If we specify a theory with all of its terms, and then replace all of those terms with variables, we can then say that some n-tuples of entities can satisfy this formula. This Ramsey sentence then says the theory is realised, without specifying by what. | |
| From: David Lewis (How to Define Theoretical Terms [1970], II) | |
| A reaction: [I have compressed Lewis, and cut out the symbolism] |
| 6894 | Mental terms can be replaced in a sentence by a variable and an existential quantifier [Ramsey] |
| Full Idea: Ramsey Sentences are his technique for eliminating theoretical terms in science (and can be applied to mental terms, or to social rights); a term in a sentence is replaced by a variable and an existential quantifier. | |
| From: Frank P. Ramsey (Law and Causality [1928]), quoted by Thomas Mautner - Penguin Dictionary of Philosophy p.469 | |
| A reaction: The technique is used by functionalists and results in a sort of eliminativism. The intrinsic nature of mental states is eliminated, because everything worth saying can be expressed in terms of functional/causal role. Sounds wrong to me. |
| 15526 | There is a method for defining new scientific terms just using the terms we already understand [Lewis] |
| Full Idea: I contend that there is a general method for defining newly introduced terms in a scientific theory, one which uses only the old terms we understood beforehand. | |
| From: David Lewis (How to Define Theoretical Terms [1970], Intro) | |
| A reaction: Lewis is game is to provide bridge laws for a reductive account of nature, without having to introduce something entirely new to achieve it. The idea of bridge laws in scientific theory is less in favour these days. |
| 15529 | It is better to have one realisation of a theory than many - but it may not always be possible [Lewis] |
| Full Idea: A uniquely realised theory is, other things being equal, certainly more satisfactory than a multiply realised theory. We should insist on unique realisation as a standard of correctness unless it is a standard too high to be met. | |
| From: David Lewis (How to Define Theoretical Terms [1970], III) | |
| A reaction: The point is that rewriting a theory as Ramsey sentences just says there is at least one realisation, and so it doesn't meet the highest standards for scientific theories. The influence of set-theoretic model theory is obvious in this approach. |
| 15531 | The Ramsey sentence of a theory says that it has at least one realisation [Lewis] |
| Full Idea: The Ramsey sentence of a theory says that it has at least one realisation. | |
| From: David Lewis (How to Define Theoretical Terms [1970], V) |
| 9418 | All knowledge needs systematizing, and the axioms would be the laws of nature [Ramsey] |
| Full Idea: Even if we knew everything, we should still want to systematize our knowledge as a deductive system, and the general axioms in that system would be the fundamental laws of nature. | |
| From: Frank P. Ramsey (Law and Causality [1928], §A) | |
| A reaction: This is the Mill-Ramsey-Lewis view. Cf. Idea 9420. |
| 9420 | Causal laws result from the simplest axioms of a complete deductive system [Ramsey] |
| Full Idea: Causal laws are consequences of those propositions which we should take as axioms if we knew everything and organized it as simply as possible in a deductive system. | |
| From: Frank P. Ramsey (Law and Causality [1928], §B) | |
| A reaction: Cf. Idea 9418. |