9 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) |
| 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. |
| 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) |
| 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. |
| 8406 | Not all explanations are causal, but if a thing can be explained at all, it can be explained causally [Sanford] |
| Full Idea: Although not all explanations are causal, anything which can be explained in any way can be explained causally. | |
| From: David H. Sanford (Causation [1995], p.79) | |
| A reaction: A nice bold claim with which I am in sympathy, but he would have a struggle proving it. Does this imply that causal explanations are basic, or in some way superior? Note that functional explanations would thus have underlying causal explanations. |
| 19739 | The maxim for suicide is committed to the value of life, and is thus contradictory [Kant] |
| Full Idea: If my maxim is to shorten my life if its continuance threatens more evil than pleasure ...it is seen that a system of nature by whose law the feeling intended to further life should actually destroy life would contradict itself, and could not subsist. | |
| From: Immanuel Kant (Lectures on Ethics [1780], 422:53) | |
| A reaction: [compressed] I take it this means that a potential suicide is assessing what is best for life, and is therefore implicitly committed to life. Not persuasive! Should we not terminate the life of a mass murderer in mid-crime? |
| 8407 | A totality of conditions necessary for an occurrence is usually held to be jointly sufficient for it [Sanford] |
| Full Idea: A totality of conditions necessary for an occurrence is jointly sufficient for it. This is a widely held but controversial view, and it is not a logical truth. | |
| From: David H. Sanford (Causation [1995], p.82) | |
| A reaction: This wouldn't work for an impossible occurrence. What are the necessary conditions to produce a large planet made of uranium? One of them would have to be a naturally impossible necessity. |