26 ideas
| 3853 | For science to be rational, we must explain scientific change rationally [Newton-Smith] |
| Full Idea: We are only justified in regarding scientific practice as the very paradigm of rationality if we can justify the claim that scientific change is rationally explicable. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], I.2) |
| 3859 | We do not wish merely to predict, we also want to explain [Newton-Smith] |
| Full Idea: We do not wish merely to predict, we also want to explain. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], II.3) |
| 3870 | The real problem of science is how to choose between possible explanations [Newton-Smith] |
| Full Idea: Once we move beyond investigating correlations between observables the question of what does or should guide our choice between alternative explanatory accounts becomes problematic. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], IX.2) |
| 3855 | Critics attack positivist division between theory and observation [Newton-Smith] |
| Full Idea: The critics of positivism attacked the conception of a dichotomy between theory and observation. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], I.4) |
| 3854 | Positivists hold that theoretical terms change, but observation terms don't [Newton-Smith] |
| Full Idea: For positivists it was taken that while theory change meant change in the meaning of theoretical terms, the meaning of observational terms was invariant under theory change. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], I.4) |
| 3869 | More truthful theories have greater predictive power [Newton-Smith] |
| Full Idea: If a theory is a better approximation to the truth, then it is likely that it will have greater predictive power. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], VIII.8) |
| 3861 | Theories generate infinite truths and falsehoods, so they cannot be used to assess probability [Newton-Smith] |
| Full Idea: We cannot explicate a useful notion of verisimilitude in terms of the number of truths and the number of falsehoods generated by a theory, because they are infinite. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], III.4) |
| 14970 | Normal system K has five axioms and rules [Cresswell] |
| Full Idea: Normal propositional modal logics derive from the minimal system K: wffs of PC are axioms; □(p⊃q)⊃(□p⊃□q); uniform substitution; modus ponens; necessitation (α→□α). | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1) |
| 14971 | D is valid on every serial frame, but not where there are dead ends [Cresswell] |
| Full Idea: If a frame contains any dead end or blind world, then D is not valid on that frame, ...but D is valid on every serial frame. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1.1) |
| 14972 | S4 has 14 modalities, and always reduces to a maximum of three modal operators [Cresswell] |
| Full Idea: In S4 there are exactly 14 distinct modalities, and any modality may be reduced to one containing no more than three modal operators in sequence. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1.2) | |
| A reaction: The significance of this may be unclear, but it illustrates one of the rewards of using formal systems to think about modal problems. There is at least an appearance of precision, even if it is only conditional precision. |
| 14973 | In S5 all the long complex modalities reduce to just three, and their negations [Cresswell] |
| Full Idea: S5 contains the four main reduction laws, so the first of any pair of operators may be deleted. Hence all but the last modal operator may be deleted. This leaves six modalities: p, ◊p, □p, and their negations. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1.2) |
| 14976 | Reject the Barcan if quantifiers are confined to worlds, and different things exist in other worlds [Cresswell] |
| Full Idea: If one wants the quantifiers in each world to range only over the things that exist in that world, and one doesn't believe that the same things exist in every world, one would probably not want the Barcan formula. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.2.2) | |
| A reaction: I haven't quite got this, but it sounds to me like I should reject the Barcan formula (but Idea 9449!). I like a metaphysics to rest on the actual world (with modal properties). I assume different things could have existed, but don't. |
| 14974 | A relation is 'Euclidean' if aRb and aRc imply bRc [Cresswell] |
| Full Idea: A relation is 'Euclidean' if aRb and aRc imply bRc. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.1.2) | |
| A reaction: If a thing has a relation to two separate things, then those two things will also have that relation between them. If I am in the same family as Jim and as Jill, then Jim and Jill are in the same family. |
| 14975 | A de dicto necessity is true in all worlds, but not necessarily of the same thing in each world [Cresswell] |
| Full Idea: A de dicto necessary truth says that something is φ, that this proposition is a necessary truth, i.e. that in every accessible world something (but not necessarily the same thing in each world) is φ. | |
| From: Max J. Cresswell (Modal Logic [2001], 7.2.1) | |
| A reaction: At last, a really clear and illuminating account of this term! The question is then invited of what is the truthmaker for a de dicto truth, assuming that the objects themselves are truthmakers for de re truths. |
| 3867 | De re necessity arises from the way the world is [Newton-Smith] |
| Full Idea: A necessary truth is 'de re' if its necessity arises from the way the world is. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], VII.6) |
| 3872 | We must assess the truth of beliefs in identifying them [Newton-Smith] |
| Full Idea: We cannot determine what someone's beliefs are independently of assessing to some extent the truth or falsity of the beliefs. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], X.4) |
| 3857 | Defeat relativism by emphasising truth and reference, not meaning [Newton-Smith] |
| Full Idea: The challenge of incommensurability can be met once it is realised that in comparing theories the notions of truth and reference are more important than that of meaning. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], I.6) |
| 3858 | A full understanding of 'yellow' involves some theory [Newton-Smith] |
| Full Idea: A full grasp of the concept '…is yellow' involves coming to accept as true bits of theory; that is, generalisations involving the term 'yellow'. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], II.2) |
| 3862 | All theories contain anomalies, and so are falsified! [Newton-Smith] |
| Full Idea: According to Feyerabend all theories are born falsified, because no theory has ever been totally free of anomalies. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], III.9) |
| 3863 | The anomaly of Uranus didn't destroy Newton's mechanics - it led to Neptune's discovery [Newton-Smith] |
| Full Idea: When scientists observed the motion of Uranus, they did not give up on Newtonian mechanics. Instead they posited the existence of Neptune. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], III.9) |
| 3864 | Anomalies are judged against rival theories, and support for the current theory [Newton-Smith] |
| Full Idea: Whether to reject an anomaly has to be decided on the basis of the availability of a rival theory, and on the basis of the positive evidence for the theory in question. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], III.9) |
| 3865 | Why should it matter whether or not a theory is scientific? [Newton-Smith] |
| Full Idea: Why should it be so important to distinguish between theories that are scientific and those that are not? | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], IV.3) |
| 3866 | If theories are really incommensurable, we could believe them all [Newton-Smith] |
| Full Idea: If theories are genuinely incommensurable why should I be faced with the problem of choosing between them? Why not believe them all? | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], VII.1) |
| 3871 | Explaining an action is showing that it is rational [Newton-Smith] |
| Full Idea: To explain an action as an action is to show that it is rational. | |
| From: W.H. Newton-Smith (The Rationality of Science [1981], X.2) |
| 16713 | Philosophers are the forefathers of heretics [Tertullian] |
| Full Idea: Philosophers are the forefathers of heretics. | |
| From: Tertullian (works [c.200]), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 20.2 |
| 6610 | I believe because it is absurd [Tertullian] |
| Full Idea: I believe because it is absurd ('Credo quia absurdum est'). | |
| From: Tertullian (works [c.200]), quoted by Robert Fogelin - Walking the Tightrope of Reason n4.2 | |
| A reaction: This seems to be a rather desperate remark, in response to what must have been rather good hostile arguments. No one would abandon the support of reason if it was easy to acquire. You can't deny its engaging romantic defiance, though. |