39 ideas
| 14273 | Conditional Proof is only valid if we accept the truth-functional reading of 'if' [Edgington] |
| Full Idea: Conditional Proof seems sound: 'From X and Y, it follows that Z. So from X it follows that if Y,Z'. Yet for no reading of 'if' which is stronger that the truth-functional reading is CP valid, at least if we accept ¬(A&¬B);A; therefore B. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 2.2) | |
| A reaction: See the section of ideas on Conditionals (filed under 'Modality') for a fuller picture of this issue. Edgington offers it as one of the main arguments in favour of the truth-functional reading of 'if' (though she rejects that reading). |
| 12205 | There are two families of modal notions, metaphysical and epistemic, of equal strength [Edgington] |
| Full Idea: In my view, there are two independent families of modal notions, metaphysical and epistemic, neither stronger than the other. | |
| From: Dorothy Edgington (Two Kinds of Possibility [2004], Abs) | |
| A reaction: My immediate reaction is that epistemic necessity is not necessity at all. 'For all I know' 2 plus 2 might really be 95, and squares may also be circular. |
| 12207 | Metaphysical possibility is discovered empirically, and is contrained by nature [Edgington] |
| Full Idea: Metaphysical necessity derives from distinguishing things which can happen and things which can't, in virtue of their nature, which we discover empirically: the metaphysically possible, I claim, is constrained by the laws of nature. | |
| From: Dorothy Edgington (Two Kinds of Possibility [2004], §I) | |
| A reaction: She claims that Kripke is sympathetic to this. Personally I like the idea that natural necessity is metaphysically necessary (see 'Scientific Essentialism'), but the other way round comes as a bit of a surprise. I will think about it. |
| 12206 | Broadly logical necessity (i.e. not necessarily formal logical necessity) is an epistemic notion [Edgington] |
| Full Idea: So-called broadly logical necessity (by which I mean, not necessarily formal logical necessity) is an epistemic notion. | |
| From: Dorothy Edgington (Two Kinds of Possibility [2004], §I) | |
| A reaction: This is controversial, and is criticised by McFetridge and Rumfitt. Fine argues that 'narrow' (formal) logical necessity is metaphysical. Between them they have got rid of logical necessity completely. |
| 12185 | Logical necessity is epistemic necessity, which is the old notion of a priori [Edgington, by McFetridge] |
| Full Idea: Edgington's position is that logical necessity is an epistemic notion: epistemic necessity which, she claims, is the old notion of the a priori. Like Kripke, she thinks this is two-way independent of metaphysical necessity. | |
| From: report of Dorothy Edgington (Epistemic and Metaphysical Possibility [1985]) by Ian McFetridge - Logical Necessity: Some Issues §1 | |
| A reaction: [her paper was unpublished] She hence thinks an argument can be logically valid, while metaphysically its conclusion may not follow. Dubious, though I think I favour the view that logical necessity is underwritten by metaphysical necessity. |
| 12208 | An argument is only valid if it is epistemically (a priori) necessary [Edgington] |
| Full Idea: Validity is governed by epistemic necessity, i.e. an argument is valid if and only if there is an a priori route from premises to conclusion. | |
| From: Dorothy Edgington (Two Kinds of Possibility [2004], §V) | |
| A reaction: Controversial, and criticised by McFetridge and Rumfitt. I don't think I agree with her. I don't see validity as depending on dim little human beings. |
| 13857 | Truth-functional possibilities include the irrelevant, which is a mistake [Edgington] |
| Full Idea: How likely is a fair die landing on an even number to land six? My approach is, assume an even number, so three possibilities, one a six, so 'one third'; the truth-functional approach is it's true if it is not-even or six, so 'two-thirds'. | |
| From: Dorothy Edgington (Do Conditionals Have Truth Conditions? [1986], 3) | |
| A reaction: The point is that in the truth-functional approach, if the die lands not-even, then the conditional comes out as true, when she says it should be irrelevant. She seems to be right about this. |
| 14281 | A thing works like formal probability if all the options sum to 100% [Edgington] |
| Full Idea: One's degrees of belief in the members of an idealised partition should sum to 100%. That is all there is to the claim that degrees of belief should have the structure of probabilities. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 3.1) |
| 14284 | Conclusion improbability can't exceed summed premise improbability in valid arguments [Edgington] |
| Full Idea: If (and only if) an argument is valid, then in no probability distribution does the improbability of its conclusion exceed the sum of the improbabilities of its premises. We can call this the Probability Preservation Principle. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 3.2) | |
| A reaction: [Ernest Adams is credited with this] This means that classical logic is in some way probability-preserving as well as truth-preserving. |
| 13768 | Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington] |
| Full Idea: If your interest in logic is confined to applications to mathematics or other a priori matters, it is fine for validity to preserve certainty, ..but if you use conditionals when arguing about contingent matters, then great caution will be required. | |
| From: Dorothy Edgington (Conditionals [2001], 17.2.1) |
| 13853 | It is a mistake to think that conditionals are statements about how the world is [Edgington] |
| Full Idea: The mistake philosophers have made, in trying to understand the conditional, is to assume that its function is to make a statement about how the world is (or how other possible worlds are related to it), true or false, as the case may be. | |
| From: Dorothy Edgington (Do Conditionals Have Truth Conditions? [1986], 1) | |
| A reaction: 'If pigs could fly we would never catch them' may not be about the world, but 'if you press this switch the light comes on' seems to be. Actually even the first one is about the world. I've an inkling that Edgington is wrong about this. Powers! |
| 14270 | Simple indicatives about past, present or future do seem to form a single semantic kind [Edgington] |
| Full Idea: Straightforward statements about the past, present or future, to which a conditional clause is attached - the traditional class of indicative conditionals - do (in my view) constitute a single semantic kind. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 1) | |
| A reaction: This contrasts with Idea 14269, where the future indicatives are group instead with the counterfactuals. |
| 14269 | Maybe forward-looking indicatives are best classed with the subjunctives [Edgington] |
| Full Idea: According to some theorists, the forward-looking 'indicatives' (those with a 'will' in the main clause) belong with the 'subjunctives' (those with a 'would' in the main clause), and not with the other 'indicatives'. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 1) | |
| A reaction: [She cites Gibbard, Dudman and 1988 Bennett; Jackson defends the indicative/subjunctive division, and recent Bennett defends it too] It is plausible to say that 'If you will do x' is counterfactual, since it hasn't actually happened. |
| 13770 | There are many different conditional mental states, and different conditional speech acts [Edgington] |
| Full Idea: As well as conditional beliefs, there are conditional desires, hopes, fears etc. As well as conditional statements, there are conditional commands, questions, offers, promises, bets etc. | |
| From: Dorothy Edgington (Conditionals [2001], 17.3.4) |
| 14275 | Truth-function problems don't show up in mathematics [Edgington] |
| Full Idea: The main defects of the truth-functional account of conditionals don't show up in mathematics. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 2.3) | |
| A reaction: These problems are the paradoxes associated with the material conditional ⊃. Too often mathematical logic has been the tail that wagged the dog in modern philosophy. |
| 13764 | Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington] |
| Full Idea: Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? Are they non-truth-functional, like 'because' or 'before'? Do the values of A and B, in some cases, leave open the value of 'If A,B'? | |
| From: Dorothy Edgington (Conditionals [2001], 17.1) | |
| A reaction: I would say they are not truth-functional, because the 'if' asserts some further dependency relation that goes beyond the truth or falsity of A and B. Logical ifs, causal ifs, psychological ifs... The material conditional ⊃ is truth-functional. |
| 13765 | 'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington] |
| Full Idea: If it were possible to have A true, B false, and If A,B true, it would be unsafe to infer B from A and If A,B: modus ponens would thus be invalid. Hence 'If A,B' must entail ¬(A & ¬B). | |
| From: Dorothy Edgington (Conditionals [2001], 17.1) | |
| A reaction: This is a firm defence of part of the truth-functional view of conditionals, and seems unassailable. The other parts of the truth table are open to question, though, if A is false, or they are both true. |
| 14274 | Inferring conditionals from disjunctions or negated conjunctions gives support to truth-functionalism [Edgington] |
| Full Idea: If either A or B is true, then you are intuitively justified in believe that If ¬A, B. If you know that ¬(A&B), then you may justifiably infer that if A, ¬B. The truth-functionalist gets both of these cases (disjunction and negated conjunction) correct. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 2.1) | |
| A reaction: [compressed version] This summarises two of Edgington's three main arguments in favour of the truth-functional account of conditions (along with the existence of Conditional Proof). It is elementary classical logic which supports truth-functionalism. |
| 14276 | The truth-functional view makes conditionals with unlikely antecedents likely to be true [Edgington] |
| Full Idea: The truth-functional view of conditionals has the unhappy consequence that all conditionals with unlikely antecedents are likely to be true. To think it likely that ¬A is to think it likely that a sufficient condition for the truth of A⊃B obtains. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 2.3) | |
| A reaction: This is Edgington's main reason for rejecting the truth-functional account of conditionals. She says it removes our power to discriminate between believable and unbelievable conditionals, which is basic to practical reasoning. |
| 14290 | Doctor:'If patient still alive, change dressing'; Nurse:'Either dead patient, or change dressing'; kills patient! [Edgington] |
| Full Idea: The doctor says "If the patient is still alive in the morning, change the dressing". As a truth-functional command this says "Make it that either the patient is dead in the morning, or change the dressing", so the nurse kills the patient. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 5) | |
| A reaction: Isn't philosophy wonderful? |
| 13855 | A conditional does not have truth conditions [Edgington] |
| Full Idea: A conditional does not have truth conditions. | |
| From: Dorothy Edgington (Do Conditionals Have Truth Conditions? [1986], 1) |
| 13859 | X believes 'if A, B' to the extent that A & B is more likely than A & ¬B [Edgington] |
| Full Idea: X believes that if A, B, to the extent that he judges that A & B is nearly as likely as A, or (roughly equivalently) to the extent that he judges A & B to be more likely than A & ¬B. | |
| From: Dorothy Edgington (Do Conditionals Have Truth Conditions? [1986], 5) | |
| A reaction: This is a formal statement of her theory of conditionals. |
| 14271 | Non-truth-functionalist say 'If A,B' is false if A is T and B is F, but deny that is always true for TT,FT and FF [Edgington] |
| Full Idea: Non-truth-functional accounts agree that 'If A,B' is false when A is true and B is false; and that it is sometimes true for the other three combinations of truth-values; but they deny that the conditional is always true in each of these three cases. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 2.1) | |
| A reaction: Truth-functional connectives like 'and' and 'or' don't add any truth-conditions to the values of the propositions, but 'If...then' seems to assert a relationship that goes beyond its component propositions, so non-truth-functionalists are right. |
| 14272 | I say "If you touch that wire you'll get a shock"; you don't touch it. How can that make the conditional true? [Edgington] |
| Full Idea: Non-truth-functionalists agree that when A is false, 'If A,B' may be either true or false. I say "If you touch that wire, you will get an electric shock". You don't touch it. Was my remark true or false? They say it depends on the wire etc. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 2.1) | |
| A reaction: This example seems to me to be a pretty conclusive refutation of the truth-functional view. How can the conditional be implied simply by my failure to touch the wire (which is what benighted truth-functionalists seem to believe)? |
| 13854 | Conditionals express what would be the outcome, given some supposition [Edgington] |
| Full Idea: It is often necessary to suppose (or assume) that some epistemic possibility is true, and to consider what else would be the case, or would be likely to be the case, given this supposition. The conditional expresses the outcome of such thought processes. | |
| From: Dorothy Edgington (Do Conditionals Have Truth Conditions? [1986], 1) | |
| A reaction: This is the basic Edgington view. It seems to involve an active thought process, and imagination, rather than being the static semantic relations offered by possible worlds analyses. True conditionals state relationships in the world. |
| 14282 | On the supposition view, believe if A,B to the extent that A&B is nearly as likely as A [Edgington] |
| Full Idea: Accepting Ramsey's suggestion that 'if' and 'on the supposition that' come to the same thing, we get an equation which says ...you believe if A,B to the extent that you think that A&B is nearly as likely as A. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 3.1) |
| 14278 | Truth-functionalists support some conditionals which we assert, but should not actually believe [Edgington] |
| Full Idea: There are compounds of conditionals which we confidently assert and accept which, by the lights of the truth-functionalist, we do not have reason to believe true, such as 'If it broke if it was dropped, it was fragile', when it is NOT dropped. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 2.5) | |
| A reaction: [The example is from Gibbard 1981] The fact that it wasn't dropped only negates the nested antecedent, not the whole antecedent. I suppose it also wasn't broken, and both negations seem to be required. |
| 14287 | Does 'If A,B' say something different in each context, because of the possibiites there? [Edgington] |
| Full Idea: A pragmatic constraint might say that as different possibilities are live in different conversational settings, a different proposition may be expressed by 'If A,B' in different conversational settings. | |
| From: Dorothy Edgington (Conditionals (Stanf) [2006], 4.1) | |
| A reaction: Edgington says that it is only the truth of the proposition, not its content, which changes with context. I'm not so sure. 'If Hitler finds out, we are in trouble' says different things in 1914 and 1944. |
| 7647 | The imagination alone perceives all objects; it is the soul, playing all its roles [La Mettrie] |
| Full Idea: The imagination alone perceives; it forms an idea of all objects, with the words and figures that characterise them; thus the imagination is the soul, because it plays all its roles. | |
| From: Julien Offray de La Mettrie (Machine Man [1747], p.15) | |
| A reaction: This is not just a big claim for the importance of imagination, in strong opposition to Descartes's rather dismissive view (Idea 1399), but also appears to be the germ of an interesting theory about the nature of personal identity. |
| 7645 | When falling asleep, the soul becomes paralysed and weak, just like the body [La Mettrie] |
| Full Idea: The soul and body fall asleep together. The soul slowly becomes paralysed, together with all the body's muscles. They can no longer hold up the weight of the head, while the soul can no longer bear the burden of thought. | |
| From: Julien Offray de La Mettrie (Machine Man [1747], p.6) | |
| A reaction: A very nice observation, to place alongside other evidence such as drunkenness and blushing. Personally I find it hard to see why anyone ever believed dualism. You don't need modern brain scans and brain lesion research to see the problem. |
| 23225 | The soul's faculties depend on the brain, and are simply the brain's organisation [La Mettrie] |
| Full Idea: All the soul's faculties depend so much on the specific organisation of the brain and of the whole body that they are clearly nothing but that organisation. | |
| From: Julien Offray de La Mettrie (Machine Man [1747], p.26) | |
| A reaction: An interesting idea because it suggests that La Mettrie is a functionalist, rather than simply a reductive physicalist. |
| 7652 | Man is a machine, and there exists only one substance, diversely modified [La Mettrie] |
| Full Idea: Let us conclude boldly that man is a machine and that there is in the whole universe only one diversely modified substance. | |
| From: Julien Offray de La Mettrie (Machine Man [1747], p.39) | |
| A reaction: What courage it must have taken to write what now seems a perfectly acceptable and normal view. One day there should be a collective monument to Hobbes, Gassendi, Spinoza, La Mettrie and Hume, who thought so boldly. |
| 7650 | All thought is feeling, and rationality is the sensitive soul contemplating reasoning [La Mettrie] |
| Full Idea: Thought is only a capacity to feel, and the rational soul is only the sensitive soul applied to the contemplation of ideas and to reasoning. | |
| From: Julien Offray de La Mettrie (Machine Man [1747], p.33) | |
| A reaction: What a very nice idea. La Mettrie wants to bring us closer to animals. Because we can pursue a train of rational thought, it does not follow that we have a faculty called 'rationality'. A dog can follow a clever series of clues that lead to food. |
| 7651 | With wonderful new machines being made, a speaking machine no longer seems impossible [La Mettrie] |
| Full Idea: If wonderful machines like Huygens's planetary clock can be made, it would take even more cogs and springs to make a speaking machine, which can no longer be considered impossible, particularly at the hands of a new Prometheus. | |
| From: Julien Offray de La Mettrie (Machine Man [1747], p.34) | |
| A reaction: Compare Descartes in Idea 3614. The idea of artificial intelligence does not arise with the advent of computers; it follows naturally from the materialist view of the mind, along with a bit of ambition to build complex machines. |
| 22595 | Liberty is the triumph of the individual, over both despotic government and enslaving majorities [Constant] |
| Full Idea: Lliberty is the triumph of the individual, as much over a government which seeks to rule by despotic methods, as over the masses who seek to render the minority the slave of the majority. | |
| From: Benjamin Constant (Principles of Politics [1806]), quoted by Ian Dunt - How to be a Liberal 4 | |
| A reaction: [No page given] Dunt describes Constant's book as the first really systematic account of liberalism. Very important to have rights against the majority, as well as against government. |
| 22597 | Minority rights are everyone's rights, because we all have turns in the minority [Constant] |
| Full Idea: To defend the rights of minorities is to defend the rights of all. Everyone in turn finds himself in the minority. | |
| From: Benjamin Constant (Principles of Politics [1806]), quoted by Ian Dunt - How to be a Liberal 4 | |
| A reaction: Very conformist people, who are often the most oppressive, are rarely in the minority, and are unlikely to be impressed by this idea. |
| 7648 | The sun and rain weren't made for us; they sometimes burn us, or spoil our seeds [La Mettrie] |
| Full Idea: The sun was not made in order to heat the earth and all its inhabitants - whom it sometimes burns - any more than the rain was created in order to grow seeds - which it often spoils. | |
| From: Julien Offray de La Mettrie (Machine Man [1747]) | |
| A reaction: This denial of Aristotelian (and divine) teleology is as much part of the movement against religion, as are concerns about natural evil, and about the weakness of arguments for God's existence. These facts were obvious long before La Mettrie. |
| 7646 | There is no abrupt transition from man to animal; only language has opened a gap [La Mettrie] |
| Full Idea: From animals to man there is no abrupt transition. What was man before he invented words and learnt languages? An animal of a particular species, with much less natural instinct than the others. | |
| From: Julien Offray de La Mettrie (Machine Man [1747], p.13) | |
| A reaction: This shows how strongly the evolutionary idea was in the air, a century before Darwin proposed a mechanism for it. This thought is the beginning of a very new view of man, and also of a very new view of animals. |
| 7649 | There is no clear idea of the soul, which should only refer to our thinking part [La Mettrie] |
| Full Idea: The soul is merely a vain term of which we have no idea and which a good mind should use only to refer to that part of us which thinks. | |
| From: Julien Offray de La Mettrie (Machine Man [1747]) | |
| A reaction: I have always found the concept of the soul particularly baffling. It seems that it is only believed in to make immortality possible, with no other purpose to the belief, let alone evidence. I suspect that Descartes agreed with La Mettrie on this. |