17 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) |
| 15842 | An ad hominem refutation is reasonable, if it uses the opponent's assumptions [Harte,V] |
| Full Idea: Judicious use of an opponent's assumptions is quite capable of producing a perfectly reasonable ad hominem refutation of the opponent's thesis. | |
| From: Verity Harte (Plato on Parts and Wholes [2002], 1.6) |
| 15841 | Mereology began as a nominalist revolt against the commitments of set theory [Harte,V] |
| Full Idea: Historically, the evolution of mereology was associated with the desire to find alternatives to set theory for those with nomimalist qualms about the commitment to abstract objects like sets. | |
| From: Verity Harte (Plato on Parts and Wholes [2002], 1.2) | |
| A reaction: Goodman, for example. It is interesting to note that the hardline nominalist Quine, pal of Goodman, eventually accepted set theory. It is difficult to account for things by merely naming their parts. |
| 15858 | Traditionally, the four elements are just what persists through change [Harte,V] |
| Full Idea: Earth, air, fire and water, viewed as elements, are, by tradition, the leading candidates for being the things that persist through change. | |
| From: Verity Harte (Plato on Parts and Wholes [2002], 4.4) | |
| A reaction: Physics still offers us things that persist through change, as conservation laws. |
| 15848 | Mereology treats constitution as a criterion of identity, as shown in the axiom of extensionality [Harte,V] |
| Full Idea: Mereologists do suppose that constitution is a criterion of identity. This view is enshrined in the Mereological axiom of extensionality; that objects with the same parts are identical. | |
| From: Verity Harte (Plato on Parts and Wholes [2002], 3.1) | |
| A reaction: A helpful explanation of why classical mereology is a very confused view of the world. It is at least obvious that a long wall and a house are different things, even if built of identical bricks. |
| 15837 | What exactly is a 'sum', and what exactly is 'composition'? [Harte,V] |
| Full Idea: The difficulty with the claim that a whole is (just) the sum of its parts is what are we to understand by 'the sum'? ...If we say wholes are 'composites' of parts, how are we to understand the relation of composition? | |
| From: Verity Harte (Plato on Parts and Wholes [2002], 1.1) |
| 15839 | If something is 'more than' the sum of its parts, is the extra thing another part, or not? [Harte,V] |
| Full Idea: Holism inherits all the difficulties associated with the term 'sum' and adds one of its own, when it says a whole is 'more than' the sum of its parts. This seems to say it has something extra? Is this something extra a part? | |
| From: Verity Harte (Plato on Parts and Wholes [2002], 1.1) | |
| A reaction: [compressed] Most people take the claim that a thing is more than the sum of its parts as metaphorical, I would think (except perhaps emergentists about the mind, and they are wrong). |
| 15838 | The problem with the term 'sum' is that it is singular [Harte,V] |
| Full Idea: For my money, the real problem with the term 'sum' is that it is singular. | |
| From: Verity Harte (Plato on Parts and Wholes [2002], 1.1) | |
| A reaction: Her point is that the surface grammar makes you accept a unity here, with no account of what unifies it, or even whether there is a unity. Does classical mereology have a concept (as the rest of us do) of 'disunity'? |
| 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] |
| 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) |