20 ideas
| 17266 | Using modal logic, philosophers tried to handle all metaphysics in modal terms [Correia/Schnieder] |
| Full Idea: In the heyday of modal logic, philosophers typically tried to account for any metaphysical notions in modal terms. | |
| From: Correia,F/Schnieder,B (Grounding: an opinionated introduction [2012], 2.4) | |
| A reaction: Lewisian realism about possible worlds actually gets rid of purely 'modal' terms, but I suppose they include possible worlds in their remark. Annoying for modal logicians to be told they had a 'heyday' - a nice example of the rhetoric of philosophy. |
| 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! |
| 17263 | Why do rationalists accept Sufficient Reason, when it denies the existence of fundamental facts? [Correia/Schnieder] |
| Full Idea: What is most puzzling about the rationalist tradition is the steadfast certainty with which the Principle of Sufficient Reason was often accepted, since it in effect denies that there are fundamental facts. | |
| From: Correia,F/Schnieder,B (Grounding: an opinionated introduction [2012], 2.2) | |
| A reaction: A very simple and interesting observation. The principle implies either a circle of reasons, or an infinite regress of reasons. Nothing can be labelled as 'primitive' or 'foundational' or 'given'. The principle is irrational! |
| 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. |
| 17270 | Is existential dependence by grounding, or do grounding claims arise from existential dependence? [Correia/Schnieder] |
| Full Idea: We may take existential dependence to be a relation induced by certain cases of grounding, but one may also think that facts about existential dependence are prior to corresponding ground claims, and in fact ground those claims. | |
| From: Correia,F/Schnieder,B (Grounding: an opinionated introduction [2012], 4.3) | |
| A reaction: I would vote for grounding, since dependence seems more abstract, and seems to demand explanation, whereas grounding seems more like a feature of reality, and to resist further intrinsic explanation (on the whole). |
| 17268 | Grounding is metaphysical and explanation epistemic, so keep them apart [Correia/Schnieder] |
| Full Idea: To us it seems advisable to separate the objective notion of grounding, which belongs to the field of metaphysics, from the epistemically loaded notion of explanation. | |
| From: Correia,F/Schnieder,B (Grounding: an opinionated introduction [2012], 4.2) | |
| A reaction: Paul Audi is the defender of the opposite view. I'm with Audi. The 'epistemically loaded' pragmatic aspect is just contextual - that we have different interests in different aspects of the grounding on different occasions. |
| 17267 | The identity of two facts may depend on how 'fine-grained' we think facts are [Correia/Schnieder] |
| Full Idea: There is a disagreement on the issue of factual identity, concerning the 'granularity' of facts, the question of how fine-grained they are. | |
| From: Correia,F/Schnieder,B (Grounding: an opinionated introduction [2012], 3.3) | |
| A reaction: If they are very fine-grained, then no two descriptions of a supposed fact will capture the same details. If we go broadbrush, facts become fuzzy and less helpful. 'Fact' was never going to be a clear term. |
| 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. |
| 19594 | General statements about nature are not valid [Novalis] |
| Full Idea: General statements are not valid in the study of nature. | |
| From: Novalis (Last Fragments [1800], 17) | |
| A reaction: This is his striking obsession with the particularity and fine detail of nature. Alexander von Humbolt was exploring nature in S.America in this year. It sounds wrong about physics, but possibly right about biology. |
| 19596 | The whole body is involved in the formation of thoughts [Novalis] |
| Full Idea: In the formation of thoughts all parts of the body seem to me to be working together. | |
| From: Novalis (Last Fragments [1800], 20) | |
| A reaction: I can only think that Spinoza must be behind this thought, or La Mettrie. It seems a strikingly unusual intuition for its time, when almost everyone takes a spiritual sort of dualism for granted. |
| 19593 | Persons are shaped by a life history; splendid persons are shaped by world history [Novalis] |
| Full Idea: What is it that shapes a person if not his life history? And in the same way a splendid person is shaped by nothing other than world history. Many people live better in the past and in the future than in the present. | |
| From: Novalis (Last Fragments [1800], 15) | |
| A reaction: Clearly there is a lot to be said for splendid people who live entirely in the present (such as jazz musicians). Some people do have an awesomely wide historical perspective on their immediate lives. Palaeontology is not the master discipline though! |
| 19595 | Nature is a whole, and its individual parts cannot be wholly understood [Novalis] |
| Full Idea: Nature is a whole - in which each part in itself can never be wholly understood. | |
| From: Novalis (Last Fragments [1800], 18) | |
| A reaction: This doesn't seem right when studying some item in a laboratory, but it seems undeniable when you consider the history and future of each item. |
| 19592 | The basic relations of nature are musical [Novalis] |
| Full Idea: Musical relations seem to me to be actually the basic relations of nature. | |
| From: Novalis (Last Fragments [1800], 10) | |
| A reaction: Novalis shows no signs of being a pythagorean, and then suddenly comes out with this. I suppose if you love music, this thought should float into your mind at regular intervals, because the power of music is so strong. Does he mean ratios? |