18 ideas
| 8952 | We reach 'reflective equilibrium' when intuitions and theory completely align [Fisher] |
| Full Idea: A state of 'reflective equilibrium' is when our theory and our intuitions become completely aligned | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.IV) | |
| A reaction: [Rawls made this concept famous] This is a helpful concept in trying to spell out the ideal which is the dream of believers in 'pure reason' - that there is a goal in which everything comes right. The problem is when people have different intuitions! |
| 17950 | The logos enables us to track one particular among a network of objects [Nehamas] |
| Full Idea: The logos (the definition) is a summary statement of the path within a network of objects that one will have to follow in order to locate a particular member of that network. | |
| From: Alexander Nehamas (Episteme and Logos in later Plato [1984], p.234) | |
| A reaction: I like this because it confirms that Plato (as well as Aristotle) was interested in the particulars rather than in the kinds (which I take to be general truths about particulars). |
| 17951 | A logos may be short, but it contains reference to the whole domain of the object [Nehamas] |
| Full Idea: A thing's logos, apparently short as it may be, is implicitly a very rich statement since it ultimately involves familiarity with the whole domain to which that particular object belongs. | |
| From: Alexander Nehamas (Episteme and Logos in later Plato [1984], p.234) | |
| A reaction: He may be wrong that the logos is short, since Aristotle (Idea 12292) says a definition can contain many assertions. |
| 8943 | Three-valued logic says excluded middle and non-contradition are not tautologies [Fisher] |
| Full Idea: In three-valued logic (L3), neither the law of excluded middle (p or not-p), nor the law of non-contradiction (not(p and not-p)) will be tautologies. If p has the value 'indeterminate' then so will not-p. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.I) | |
| A reaction: I quite accept that the world is full of indeterminate propositions, and that excluded middle and non-contradiction can sometimes be uncertain, but I am reluctant to accept that what is being offered here should be called 'logic'. |
| 8945 | Fuzzy logic has many truth values, ranging in fractions from 0 to 1 [Fisher] |
| Full Idea: In fuzzy logic objects have properties to a greater or lesser degree, and truth values are given as fractions or decimals, ranging from 0 to 1. Not-p is defined as 1-p, and other formula are defined in terms of maxima and minima for sets. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II) | |
| A reaction: The question seems to be whether this is actually logic, or a recasting of probability theory. Susan Haack attacks it. If logic is the study of how truth is preserved as we move between propositions, then 0 and 1 need a special status. |
| 8951 | Classical logic is: excluded middle, non-contradiction, contradictions imply all, disjunctive syllogism [Fisher] |
| Full Idea: For simplicity, we can say that 'classical logic' amounts to the truth of four sentences: 1) either p or not-p; 2) it is not the case that both p and not-p; 3) from p and not-p, infer q; 4) from p or q and not-p, infer q. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.I) | |
| A reaction: [She says there are many ways of specifying classical logic] Intuition suggests that 2 and 4 are rather hard to dispute, while 1 is ignoring some grey areas, and 3 is totally ridiculous. There is, of course, plenty of support for 3! |
| 8950 | Logic formalizes how we should reason, but it shouldn't determine whether we are realists [Fisher] |
| Full Idea: Even if one is inclined to be a realist about everything, it is hard to see why our logic should be the determiner. Logic is supposed to formalize how we ought to reason, but whether or not we should be realists is a matter of philosophy, not logic. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 09.I) | |
| A reaction: Nice to hear a logician saying this. I do not see why talk in terms of an object is a commitment to its existence. We can discuss the philosopher's stone, or Arthur's sword, or the Loch Ness monster, or gravitinos, with degrees of commitment. |
| 16052 | 'Superdupervenience' is supervenience that has a robustly materialistic explanation [Horgan,T] |
| Full Idea: The idea of a ontological supervenience that is robustly explainable in a materialistically explainable way I hereby dub 'superdupervenience'. | |
| From: Terence Horgan (From Supervenience to Superdupervenience [1993], §4) | |
| A reaction: [He credits William Lycan with the actual word] His assumption prior to this introduction is that mere supervenience just adds a new mystery. I take supervenience to be an observation of 'tracking', which presumably needs to be explained. |
| 16053 | 'Global' supervenience is facts tracking varying physical facts in every possible world [Horgan,T] |
| Full Idea: The idea of 'global supervenience' is standardly expressed as 'there are no two physically possible worlds which are exactly alike in all physical respects but different in some other respect'. | |
| From: Terence Horgan (From Supervenience to Superdupervenience [1993], §5) | |
| A reaction: [Jaegwon Kim is the source of this concept] The 'local' view will be that they do indeed track, but they could, in principle, come apart. A zombie might be a case of them possibly coming apart. Zombies are silly. |
| 16056 | Don't just observe supervenience - explain it! [Horgan,T] |
| Full Idea: Although the task of explaining supervenience has been little appreciated and little discussed in the philosophical literature, it is time for that to change. | |
| From: Terence Horgan (From Supervenience to Superdupervenience [1993], §8) | |
| A reaction: I would offer a strong addition to this: be absolutely sure that you are dealing with two distinct things in the supervenience relationship, before you waste time trying to explain how they relate to one another. |
| 16054 | Physicalism needs more than global supervenience on the physical [Horgan,T] |
| Full Idea: Global supervenience seems too weak to capture the physical facts determining all the facts. …There could be two spatio-temporal regions alike in all physical respects, but different in some intrinsic non-physical respect. | |
| From: Terence Horgan (From Supervenience to Superdupervenience [1993], §5) | |
| A reaction: I.e. there might be two physically identical regions, but one contains angels and the other doesn't (so the extra fact isn't tracking the physical facts). Physicalism I take to be the simple denial of the angels. Supervenience is an explanandum. |
| 16055 | Materialism requires that physics be causally complete [Horgan,T] |
| Full Idea: Any broadly materialistic metaphysical position needs to claim that physics is causally complete. | |
| From: Terence Horgan (From Supervenience to Superdupervenience [1993], §6) | |
| A reaction: Since 'physics' is a human creation, I presume he means that physical reality is causally complete. The interaction problem that faced Descartes seems crucial - how could something utterly non-physical effect a physical change? |
| 8946 | We could make our intuitions about heaps precise with a million-valued logic [Fisher] |
| Full Idea: We could construct a 1,000,000-valued logic that would allow our intuitions concerning a heap to vary exactly with the amount of sand in the heap. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008]) | |
| A reaction: Presumably only an infinite number of grains of sand would then produce a true heap, and even one grain would count as a bit of a heap, which must both be wrong, so I can't see this helping much. |
| 8944 | Vagueness can involve components (like baldness), or not (like boredom) [Fisher] |
| Full Idea: Vague terms come in at least two different kinds: those whose constituent parts come in discrete packets (bald, rich, red) and those that don't (beauty, boredom, niceness). | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II) | |
| A reaction: The first group seem to be features of the external world, and the second all occur in the mind. Baldness may be vague, but presumably hairs are (on the whole) not. Nature doesn't care whether someone is actually 'bald' or not. |
| 8941 | We can't explain 'possibility' in terms of 'possible' worlds [Fisher] |
| Full Idea: Explaining 'it is possible that p' by saying p is true in at least one possible world doesn't get me very far. If I don't understand what possibility is, then appealing to possible worlds is not going to do me much good. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 06.III) | |
| A reaction: This seems so blatant that I assume friends of possible worlds will have addressed the problem. Note that you will also need to understand 'possible' to define necessity as 'true in all possible worlds'. Necessarily-p is not-possibly-not-p. |
| 8947 | If all truths are implied by a falsehood, then not-p might imply both q and not-q [Fisher] |
| Full Idea: If all truths are implied by a falsehood, then 'if there are no trees in the park then there is no shade' and 'if there are no trees in the park there is plenty of shade' both come out as true. Intuitively, though, the second one is false. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.I) | |
| A reaction: The rule that a falsehood implies all truths must be the weakest idea in classical logic, if it actually implies a contradiction. This means we must take an interest in relevance logics. |
| 8949 | In relevance logic, conditionals help information to flow from antecedent to consequent [Fisher] |
| Full Idea: A good account of relevance logic suggests that a conditional will be true when the flow of information is such that a conditional is the device that helps information to flow from the antecedent to the consequent. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.III) | |
| A reaction: Hm. 'If you are going out, you'll need an umbrella'. This passes on information about 'out', but also brings in new information. 'If you are going out, I'm leaving you'. What flows is an interpretation of the antecedent. Tricky. |
| 16057 | Instrumentalism normally says some discourse is useful, but not genuinely true [Horgan,T] |
| Full Idea: Instrumentalist views typically attribute utility to the given body of discourse, but deny that it expresses genuine truths. | |
| From: Terence Horgan (From Supervenience to Superdupervenience [1993], §8) | |
| A reaction: To me it is obvious to ask why anything could have a high level of utility (especially in accounts of the external physical world) without being true. Falsehoods may sometimes (though I doubt it) be handy in human life, but useful in chemistry…? |