20 ideas
8378 | Philosophers usually learn science from each other, not from science [Russell] |
Full Idea: Philosophers are too apt to take their views on science from each other, not from science. | |
From: Bertrand Russell (On the Notion of Cause [1912], p.178) | |
A reaction: This wasn't true of Russell, but it is certainly true of me. I rely on philosophical researchers to find the interesting bits of science for me (like blindsight). Memo to myself: read more science. |
19389 | Truth is a characteristic of possible thoughts [Leibniz] |
Full Idea: Truth really belongs to the class of thoughts which are possible. | |
From: Gottfried Leibniz (Dialogue on Things and Words [1677], p.7) | |
A reaction: I like the fact that this ties truth to 'thoughts', rather than peculiar abstract unthought entities called 'propositions', but I take it that thoughts which are possible but not thought will thereby not exist, so they can't be true. |
19388 | True and false seem to pertain to thoughts, yet unthought propositions seem to be true or false [Leibniz] |
Full Idea: B: I concede that truth and falsity both pertain to thoughts and not to things. A: But this contradicts your previous opinion that a proposition remains true even when you are not thinking about it. | |
From: Gottfried Leibniz (Dialogue on Things and Words [1677], p.7) | |
A reaction: I don't trigger the truth of a proposition by thinking about it - I see that it is true. But I dislike the idea that reality is full of propositions, which seems to be mad metaphysics. So I deny unthought propositions are true, because there aren't any. |
8195 | Undecidable statements result from quantifying over infinites, subjunctive conditionals, and the past tense [Dummett] |
Full Idea: I once wrote that there are three linguistic devices that make it possible for us to frame undecidable statements: quantification over infinity totalities, as expressed by word such as 'never'; the subjunctive conditional form; and the past tense. | |
From: Michael Dummett (Truth and the Past [2001], 4) | |
A reaction: Dummett now repudiates the third one. Statements containing vague concepts also appear to be undecidable. Personally I have no problems with deciding (to a fair extent) about 'never x', and 'if x were true', and 'it was x'. |
8194 | Surely there is no exact single grain that brings a heap into existence [Dummett] |
Full Idea: There is surely no number n such that "n grains of sand do not make a heap, although n+1 grains of sand do" is true. | |
From: Michael Dummett (Truth and the Past [2001], 4) | |
A reaction: It might be argued that there is such a number, but no human being is capable of determing it. Might God know the value of n? On the whole Dummett's view seems the most plausible. |
8190 | Intuitionists rely on the proof of mathematical statements, not their truth [Dummett] |
Full Idea: The intuitionist account of the meaning of mathematical statements does not employ the notion of a statement's being true, but only that of something's being a proof of the statement. | |
From: Michael Dummett (Truth and the Past [2001], 2) | |
A reaction: I remain unconvinced that anyone could give an account of proof that didn't discreetly employ the notion of truth. What are we to make of "we suspect this is true, but no one knows how to prove it?" (e.g. Goldbach's Conjecture). |
8198 | A 'Cambridge Change' is like saying 'the landscape changes as you travel east' [Dummett] |
Full Idea: The idea of 'Cambridge Change' is like saying 'the landscape changes as you travel east'. | |
From: Michael Dummett (Truth and the Past [2001], 5) | |
A reaction: The phrase was coined in Oxford. It is a useful label with which realists can insult solipsists, idealists and other riff-raff. Four Dimensionalists seem to see time in this way. Events sit there, and we travel past them. But there are indexical events. |
8192 | I no longer think what a statement about the past says is just what can justify it [Dummett] |
Full Idea: In distinguishing between what can establish a statement about the past as true and what it is that that statement says, we are repudiating antirealism about the past. | |
From: Michael Dummett (Truth and the Past [2001], 3) | |
A reaction: This is a late shift of ground from the champion of antirealism. If Dummett's whole position is based on a 'justificationist' theory of meaning, he must surely have a different theory of meaning now for statements about the past? |
8375 | 'Necessary' is a predicate of a propositional function, saying it is true for all values of its argument [Russell] |
Full Idea: 'Necessary' is a predicate of a propositional function, meaning that it is true for all possible values of its argument or arguments. Thus 'If x is a man, x is mortal' is necessary, because it is true for any possible value of x. | |
From: Bertrand Russell (On the Notion of Cause [1912], p.175) | |
A reaction: This is presumably the intermediate definition of necessity, prior to modern talk of possible worlds. Since it is a predicate about functions, it is presumably a metalinguistic concept, like the semantic concept of truth. |
8199 | The existence of a universe without sentience or intelligence is an unintelligible fantasy [Dummett] |
Full Idea: The existence of a universe from which sentience was permanently absent is an unintelligible fantasy. What exists is what can be known to exist. What is true is what can be known to be true. Reality is what can be experienced and known. | |
From: Michael Dummett (Truth and the Past [2001], 5) | |
A reaction: This strikes me as nonsense. The fact that we cannot think about a universe without introducing a viewpoint does not mean that we cannot 'intellectually imagine' its existence devoid of viewpoints. Nothing could ever experience a star's interior. |
8193 | Verification is not an individual but a collective activity [Dummett] |
Full Idea: Verification is not an individual but a collective activity. | |
From: Michael Dummett (Truth and the Past [2001], 3) | |
A reaction: This generates problems. Are deceased members of the community included? (Yes, says Dummett). If someone speaks to angels (Blake!), do they get included? Is a majority necessary? What of weird loners? Etc. |
8189 | Truth-condition theorists must argue use can only be described by appeal to conditions of truth [Dummett] |
Full Idea: To demonstrate the necessity of a truth-conditional theory of meaning, a proponent of such a theory must argue that use cannot be described without appeal to the conditions for the truth of statements. | |
From: Michael Dummett (Truth and the Past [2001], 1) | |
A reaction: Unlike Dummett, I find that argument rather appealing. How do you decide the possible or appropriate use for a piece of language, if you don't already know what it means. Basing it all on social conventions means it could be meaningless ritual. |
8191 | The truth-conditions theory must get agreement on a conception of truth [Dummett] |
Full Idea: It is not enough for the truth-condition theorist to argue that we need the concept of truth: he must show that we should have the same conception of truth that he has. | |
From: Michael Dummett (Truth and the Past [2001], 2) | |
A reaction: Davidson invites us to accept Tarski's account of truth. It invites the question of what the theory would be like with a very robust correspondence account of truth, or a flabby rather subjective coherence view, or the worst sort of pragmatic view. |
4396 | The law of causality is a source of confusion, and should be dropped from philosophy [Russell] |
Full Idea: The law of causality, I believe, like much that passes muster among philosophers, is a relic of a bygone age, surviving, like the monarchy, only because it is erroneously supposed to do no harm. | |
From: Bertrand Russell (On the Notion of Cause [1912], p.173) | |
A reaction: A bold proposal which should be taken seriously. However, if we drop it from scientific explanation, we may well find ourselves permanently stuck with it in 'folk' explanation. What is the alternative? |
8376 | If causes are contiguous with events, only the last bit is relevant, or the event's timing is baffling [Russell] |
Full Idea: A cause is an event lasting for a finite time, but if cause and effect are contiguous then the earlier part of a changing cause can be altered without altering the effect, and a static cause will exist placidly for some time and then explode into effect. | |
From: Bertrand Russell (On the Notion of Cause [1912], p.177) | |
A reaction: [very compressed] He concludes that they can't be contiguous (and eventually rejects cause entirely). This kind of problem is the sort of thing that only bothers philosophers - the question of how anything can happen at all. Why change? |
8380 | Striking a match causes its igniting, even if it sometimes doesn't work [Russell] |
Full Idea: A may be the cause of B even if there actually are cases of B not following A. Striking a match will be the cause of its igniting, in spite of the fact that some matches are damp and fail to ignite. | |
From: Bertrand Russell (On the Notion of Cause [1912], p.185) | |
A reaction: An important point, although defenders of the constant conjunction view can cope with it. There is a further regularity between dampness of matches and their failure to strike. |
8379 | In causal laws, 'events' must recur, so they have to be universals, not particulars [Russell] |
Full Idea: An 'event' (in a statement of the 'law of causation') is intended to be something that is likely to recur, since otherwise the law becomes trivial. It follows that an 'event' is not some particular, but a universal of which there may be many instances. | |
From: Bertrand Russell (On the Notion of Cause [1912], p.179) | |
A reaction: I am very struck by this. It may be a key insight into understanding what a law of nature actually is. It doesn't follow that we must be realists about universals, but the process of abstraction from particulars is at the heart of generalisation. |
8381 | The constancy of scientific laws rests on differential equations, not on cause and effect [Russell] |
Full Idea: It is not in the sameness of causes and effects that the constancy of scientific law consists, but in sameness of relations. And even 'sameness of relations' is too simple a phrase; 'sameness of differential equations' is the only correct phrase. | |
From: Bertrand Russell (On the Notion of Cause [1912], p.186) | |
A reaction: This seems to be a commitment to the regularity view, since there is nothing more to natural law than that the variables keeping obeying the equations. It also seems to be a very instrumentalist view. |
8197 | Maybe past (which affects us) and future (which we can affect) are both real [Dummett] |
Full Idea: Maybe both the past and the future are real, determined by our current temporal perspective. Past is then events capable of having a causal influence upon events near us, and future is events we can affect, but from which we receive no information. | |
From: Michael Dummett (Truth and the Past [2001], 5) | |
A reaction: This is the Four-Dimensional view, which is opposed to Presentism. Might immediate unease is that it gives encouragement to fortune-tellers, whom I have always dismissed with 'You can't see the future, because it doesn't exist'. |
8196 | The present cannot exist alone as a mere boundary; past and future truths are rendered meaningless [Dummett] |
Full Idea: The idea that only the present is real cannot be sustained. St Augustine pointed out that the present has no duration; it is a mere boundary between past and future, and dependent on them. It also denies truth-value to statements about past or future. | |
From: Michael Dummett (Truth and the Past [2001], 5) | |
A reaction: To defend Presentism, I suspect that one must focus entirely on the activities of consciousness and short-term memory. All truths, of past or future, must refer totally to such mental events. But what could an event be if there is no enduring time? |