20 ideas
| 17962 | The truth-maker principle is that every truth has a sufficient truth-maker [Forrest] |
| Full Idea: Item x is said to be a sufficient truth-maker for truth-bearer p just in case necessarily if x exists then p is true. ...Every truth has a sufficient truth-maker. Hence, I take it, the sum of all sufficient truth-makers is a universal truth-maker. | |
| From: Peter Forrest (General Facts,Phys Necessity, and Metaph of Time [2006], 1) | |
| A reaction: Note that it is not 'necessary', because something else might make p true instead. |
| 14352 | '¬', '&', and 'v' are truth functions: the truth of the compound is fixed by the truth of the components [Jackson] |
| Full Idea: It is widely agreed that '¬', '&', and 'v' are 'truth functions': the truth value of a compound sentence formed using them is fully determined by the truth value or values of the component sentences. | |
| From: Frank Jackson (Conditionals [2006], 'Equiv') | |
| A reaction: A candidate for not being a truth function might be a conditional →, where the arrow adds something over and above the propositions it connects. The relationship has an additional truth value? Does A depend on B? |
| 3523 | Shadows are supervenient on their objects, but not reducible [Maslin] |
| Full Idea: Shadows are distinct from the physical objects casting the shadows and irreducible to them; any attempt at reduction would be incoherent, as it would entail identifying a shadow with the object of which it is a shadow. | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 6.3) | |
| A reaction: Another failure to find a decent analogy for what is claimed in property dualism. A 'shadow' is a reification of the abstract concept of an absence of light. Objects lose their shadows at dusk, but the object itself doesn't change. |
| 3517 | 'Ontology' means 'study of things which exist' [Maslin] |
| Full Idea: The word 'ontology' is derived from the Greek word 'ontia', which means 'things which exist'. | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 1.1) |
| 14360 | Possible worlds for subjunctives (and dispositions), and no-truth for indicatives? [Jackson] |
| Full Idea: Subjunctive conditionals are intimately connected with dispositional properties and causation. ...Consequently, a position some find attractive is that possible worlds theory applies to subjunctives, while the no-truth theory applies to indicatives. | |
| From: Frank Jackson (Conditionals [2006], 'Indicative') | |
| A reaction: My intuitions are to reject this and favour a unified account, where both sorts of conditionals are mappings of the relationships among the facts of actuality. Nice slogan! |
| 14353 | Modus ponens requires that A→B is F when A is T and B is F [Jackson] |
| Full Idea: Modus ponens is intuitively valid, but in A,A→B|B if A is true and B is false that must be because A→B is false. So A→B is false when A is true and B is false. | |
| From: Frank Jackson (Conditionals [2006], 'Equiv') | |
| A reaction: This is his first step in showing how the truth functional account of A→B acquires its truth table. If you are giving up the truth functional view of conditionals, presumably you are not also going to give up modus ponens? |
| 14354 | When A and B have the same truth value, A→B is true, because A→A is a logical truth [Jackson] |
| Full Idea: (A→A) is a logical truth, so some conditionals with antecedent and consequent the same truth value are true. But if '→' is a truth function, that will be true for all cases. Hence whenever A and B are alike in truth value, (A→B) is true. | |
| From: Frank Jackson (Conditionals [2006], 'Equiv') | |
| A reaction: His second step in demonstrating the truth table for →, assuming it is truth functional. |
| 14355 | (A&B)→A is a logical truth, even if antecedent false and consequent true, so it is T if A is F and B is T [Jackson] |
| Full Idea: (A&B)→A is a logical truth, but A can be true and B false, so that (A&B) is false. So some conditionals with false antecedent and true consequent are true. If → is a truth function, then whenever A is false and B is true (A→B) is true. | |
| From: Frank Jackson (Conditionals [2006], 'Equiv') | |
| A reaction: This is his third and final step in showing the truth table of → if it is truth functional. |
| 14358 | In the possible worlds account of conditionals, modus ponens and modus tollens are validated [Jackson] |
| Full Idea: In the possible worlds account modus ponens is validated (the closest world, the actual, is a B-world just if B is true), and modus tollens is validated (if B is false, the actual world is not an A-world, so A is false). | |
| From: Frank Jackson (Conditionals [2006], 'Famous') | |
| A reaction: [see Jackson for slightly fuller versions] This looks like a minimal requirement for a decent theory of conditionals, so Jackson explains the attractions of the possible worlds view very persuasively. |
| 14359 | Only assertions have truth-values, and conditionals are not proper assertions [Jackson] |
| Full Idea: In the no-truth theory of conditionals they have justified assertion or acceptability conditions but not truth conditions. ...The motivation is that only assertions have truth values, and conditionals are arguments, not proper assertions. | |
| From: Frank Jackson (Conditionals [2006], 'No-truth') | |
| A reaction: Once I trim this idea down to its basics, it suddenly looks very persuasive. Except that I am inclined to think that conditional truths do state facts about the world - perhaps as facts about how more basic truths are related to each other. |
| 14357 | Possible worlds account, unlike A⊃B, says nothing about when A is false [Jackson] |
| Full Idea: In the possible worlds account of conditionals A⊃B is not sufficient for A→B. If A is false then A⊃B is true, but here nothing is implied about whether the world most like the actual world except that A is true is or is not a B-world. | |
| From: Frank Jackson (Conditionals [2006], 'Possible') | |
| A reaction: The possible worlds account seems to be built on Ramsey's idea of just holding A true and seeing what you get. Being committed to B being automatically true if A is false seems highly counterintuitive. |
| 14356 | We can't insist that A is relevant to B, as conditionals can express lack of relevance [Jackson] |
| Full Idea: One addition to the truth functional account of conditionals is that A be somehow relevant to B. However, sometimes we use conditionals to express lack of relevance, as in 'If Fred works he will fail, and if Fred doesn't work he will fail'. | |
| From: Frank Jackson (Conditionals [2006], 'Possible') | |
| A reaction: This certainly seems to put paid to an attractive instant solution to the problem. |
| 3538 | Analogy to other minds is uncheckable, over-confident and chauvinistic [Maslin] |
| Full Idea: The argument from analogy makes it impossible to check my inductive inferences because of the privacy of other minds; it also seems irresponsible to generalise from a single case; and it seems like a case of human chauvinism. | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 8.2) | |
| A reaction: Privacy of other minds need not imply scepticism about them. I'm a believer, so I have no trouble checking my theories. Solipsists can't 'check' anything. It isn't 'irresponsible' to generalise from one case if that is all you have. |
| 3540 | If we are brains then we never meet each other [Maslin] |
| Full Idea: If I am my brain this leads to the odd result that you have never met me because you have never seen my brain. | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 10.7) | |
| A reaction: 'Star Trek' is full of aliens who appear beautiful, and turn out to be ugly grey lumps. 'I am my face' would be just as odd, particularly if I were in a coma, or dead. |
| 3518 | I'm not the final authority on my understanding of maths [Maslin] |
| Full Idea: I may be the final authority on whether my shoe pinches, but I am manifestly not the final authority on whether I understand some mathematical theorem. | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 1.7) | |
| A reaction: However, it doesn't follow that his teachers are the final authority either, because he may get correct answers by an algorithm, and bluff his way when demonstrating his understanding. Who knows whether anyone really understands anything? |
| 3530 | Denial of purely mental causation will lead to epiphenomenalism [Maslin] |
| Full Idea: If mental events are causally efficacious only by virtue of their physical features and not their mental ones, …then anomalous monism leads straight to ephiphenomenalism. | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 7.6) | |
| A reaction: As epiphenomenalism strikes me as being incoherent (see Idea 7379), what this amounts to is that either mental effects are causally efficacious, or they are not worth mentioning. I take them to be causally efficacious because they are brain events. |
| 3520 | Token-identity removes the explanatory role of the physical [Maslin] |
| Full Idea: In token-identity mental and physical features seem as unrelated as colour and shape, which is very weak physicalism because it does not allow physical states an explanatory role in accounting for mental states. | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 3.8.6) | |
| A reaction: Colour and shape are not totally unrelated, as they can both be totally explained by a full knowledge of the physical substance involved. ...But maybe if we fully understood Spinoza's single substance...? See Idea 4834. |
| 3528 | Causality may require that a law is being followed [Maslin] |
| Full Idea: The principle of nomological causality says that if two events are intrinsically causally related, there must be a strict physical law under which they can be subsumed. | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 7.5) |
| 3525 | Strict laws make causation logically necessary [Maslin] |
| Full Idea: 'Deductive-nomological' explanation consists of two premises - a strict law with no exceptions and supporting deterministic counterfactuals, and a statement of an event which falls under the law - which together logically require the effect. | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 7.4) |
| 3527 | Strict laws allow no exceptions and are part of a closed system [Maslin] |
| Full Idea: 'Strict' laws of nature contain no ceteris paribus clauses ('all things being equal'), and are part of a closed system (so that whatever affects the system must be included within the system). | |
| From: Keith T. Maslin (Introduction to the Philosophy of Mind [2001], 7.5) |