25 ideas
| 21793 | Genuine truth is the resolution of the highest contradiction [Hegel] |
| Full Idea: The highest truth, truth as such, is the resolution of the highest opposition and contradiction. | |
| From: Georg W.F.Hegel (Lectures on Aesthetics [1826], I: 99), quoted by Stephen Houlgate - An Introduction to Hegel 09 'Art' | |
| A reaction: Uneasy about the word 'highest', and the general Hegelian dream of 'resolving' contradictions, rather than just eliminating at least one component of them. No one else uses the word 'truth' like this. I suppose this Truth has a capital 'T'. |
| 21795 | What I hold true must also be part of my feelings and character [Hegel] |
| Full Idea: Whatever I hold as true, whatever ought to be valid for me, must also be in my feeling, must belong to my being and character. | |
| From: Georg W.F.Hegel (Lectures on Aesthetics [1826], I: 97), quoted by Stephen Houlgate - An Introduction to Hegel 09 'Philosophy' | |
| A reaction: I can see that truths do tend to become part of our character, but not that they ought to do so. I suppose I try to live my life enmeshed in the many truths which I have personally selected from the maelstrom of possibilities that engulf us. |
| 7786 | Propositional logic handles negation, disjunction, conjunction; predicate logic adds quantifiers, predicates, relations [Girle] |
| Full Idea: Propositional logic can deal with negation, disjunction and conjunction of propositions, but predicate logic goes beyond it to deal with quantifiers, predicates and relations. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.1) | |
| A reaction: This is on the first page of an introduction to the next stage, which is to include modal notions like 'must' and 'possibly'. |
| 7798 | There are three axiom schemas for propositional logic [Girle] |
| Full Idea: The axioms of propositional logic are: A→(B→A); A→(B→C)→(A→B)→(A→C) ; and (¬A→¬B)→(B→A). | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 6.5) |
| 7799 | Proposition logic has definitions for its three operators: or, and, and identical [Girle] |
| Full Idea: The operators of propositional logic are defined as follows: 'or' (v) is not-A implies B; 'and' (ampersand) is not A-implies-not-B; and 'identity' (three line equals) is A-implies-B and B-implies-A. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 6.5) |
| 7797 | Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems [Girle] |
| Full Idea: An axiom system for a logic contains three elements: a set of axioms; a set of inference rules; and definitions for proofs and theorems. There are also definitions for the derivation of conclusions from sets of premises. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 6.5) |
| 7794 | There are seven modalities in S4, each with its negation [Girle] |
| Full Idea: In S4 there are fourteen modalities: no-operator; necessarily; possibly; necessarily-possibly; possibly-necessarily; necessarily-possibly-necessarily; and possibly-necessarily-possibly (each with its negation). | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 3.5) | |
| A reaction: This is said to be 'more complex' than S5, but also 'weaker'. |
| 7793 | ◊p → □◊p is the hallmark of S5 [Girle] |
| Full Idea: The critical formula that distinguishes S5 from all others is: ◊p → □◊p. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 3.3) | |
| A reaction: If it is possible that it is raining, then it is necessary that it is possible that it is raining. But if it is possible in this world, how can that possibility be necessary in all possible worlds? |
| 7795 | S5 has just six modalities, and all strings can be reduced to those [Girle] |
| Full Idea: In S5 there are six modalities: no-operator; necessarily; and possibly (and their negations). In any sequence of operators we may delete all but the last to gain an equivalent formula. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 3.5) | |
| A reaction: Such drastic simplification seems attractive. Is there really no difference, though, between 'necessarily-possibly', 'possibly-possibly' and just 'possibly'? Could p be contingently possible in this world, and necessarily possible in another? |
| 7787 | Possible worlds logics use true-in-a-world rather than true [Girle] |
| Full Idea: In possible worlds logics a statement is true-in-a-world rather than just true. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.1) | |
| A reaction: This sounds relativist, but I don't think it is. It is the facts which change, not the concept of truth. So 'donkeys can talk' may be true in a world, but not in the actual one. |
| 7788 | Modal logic has four basic modal negation equivalences [Girle] |
| Full Idea: The four important logical equivalences in modal logic (the Modal Negation equivalences) are: ¬◊p↔□¬p, ◊¬p↔¬□p, □p↔¬◊¬p, and ◊p↔¬□¬p. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.2) | |
| A reaction: [Possibly is written as a diamond, necessarily a square] These are parallel to a set of equivalences between quantifiers in predicate logic. They are called the four 'modal negation (MN) equivalences'. |
| 7796 | Modal logics were studied in terms of axioms, but now possible worlds semantics is added [Girle] |
| Full Idea: Modal logics were, for a long time, studied in terms of axiom systems. The advent of possible worlds semantics made it possible to study them in a semantic way as well. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 6.5) |
| 7789 | Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle] |
| Full Idea: Necessary implication is often called 'strict implication'. The sort of strict implication found in valid arguments, where the conjunction of the premises necessarily implies the conclusion, is often called 'entailment'. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.2) | |
| A reaction: These are basic concept for all logic. |
| 7790 | If an argument is invalid, a truth tree will indicate a counter-example [Girle] |
| Full Idea: The truth trees method for establishing the validity of arguments and formulas is easy to use, and has the advantage that if an argument or formula is not valid, then a counter-example can be retrieved from the tree. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 1.4) |
| 10245 | One geometry cannot be more true than another [Poincaré] |
| Full Idea: One geometry cannot be more true than another; it can only be more convenient. | |
| From: Henri Poincaré (Science and Method [1908], p.65), quoted by Stewart Shapiro - Philosophy of Mathematics | |
| A reaction: This is the culminating view after new geometries were developed by tinkering with Euclid's parallels postulate. |
| 7800 | Analytic truths are divided into logically and conceptually necessary [Girle] |
| Full Idea: It has been customary to see analytic truths as dividing into the logically necessary and the conceptually necessary. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 7.3) | |
| A reaction: I suspect that this neglected distinction is important in discussions of Quine's elimination of the analytic/synthetic distinction. Was Quine too influenced by what is logically necessary, which might shift with a change of axioms? |
| 7801 | Possibilities can be logical, theoretical, physical, economic or human [Girle] |
| Full Idea: Qualified modalities seem to form a hierarchy, if we say that 'the possibility that there might be no hunger' is possible logically, theoretically, physically, economically, and humanly. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 7.3) | |
| A reaction: Girle also mentions conceptual possibility. I take 'physically' to be the same as 'naturally'. I would take 'metaphysically' possible to equate to 'theoretically' rather than 'logically'. Almost anything might be logically possible, with bizarre logic. |
| 7792 | A world has 'access' to a world it generates, which is important in possible worlds semantics [Girle] |
| Full Idea: When one world generates another then it has 'access' to the world it generated. The accessibility relation between worlds is very important in possible worlds semantics. | |
| From: Rod Girle (Modal Logics and Philosophy [2000], 3.2) | |
| A reaction: This invites the obvious question what is meant by 'generates'. |
| 18549 | Nineteenth century aesthetics focused on art rather than nature (thanks to Hegel) [Hegel, by Scruton] |
| Full Idea: Only In the course of the nineteenth century, and in the wake of Hegel's posthumously published lectures on aesthetics, did the topic of art come to replace that of natural beauty as the core subject-matter of aesthetics. | |
| From: report of Georg W.F.Hegel (Lectures on Aesthetics [1826], 5) by Roger Scruton - Beauty: a very short introduction |
| 22043 | Hegel largely ignores aesthetic pleasure, taste and beauty, and focuses on the meaning of artworks [Hegel, by Pinkard] |
| Full Idea: Unlike his predecessors (including Kant), Hegel does not focus on aesthetic pleasure, nor on good taste, nor even on the nature and criteria for beauty. Instead he focuses on the meaning of artworks and their role in forming mankind's self-consciousness. | |
| From: report of Georg W.F.Hegel (Lectures on Aesthetics [1826]) by Terry Pinkard - German Philosophy 1760-1860 11 | |
| A reaction: Personally I dislike over-intellectualising art. The aim of a work of art is to give a certain experience, not to generate an ensuing sequence of theorising. I doubt whether Vermeer had any 'meaning' in mind in his obsessive work. |
| 22042 | Natural beauty is unimportant, because it doesn't show human freedom [Hegel, by Pinkard] |
| Full Idea: Hegel thinks that natural beauty is of no real significance since it cannot display our freedom to us; nature per se is meaningless. | |
| From: report of Georg W.F.Hegel (Lectures on Aesthetics [1826]) by Terry Pinkard - German Philosophy 1760-1860 11 | |
| A reaction: Presumably freedom is in the creation, and so creativity is what matters in aesthetics. But what are the criteria of good creativity? |
| 20413 | For Hegel the importance of art concerns the culture, not the individual [Hegel, by Eldridge] |
| Full Idea: Hegel locates the significance of art in its role in cultural life in general, not in relation to the psychological needs of individuals. | |
| From: report of Georg W.F.Hegel (Lectures on Aesthetics [1826]) by Richard Eldridge - G.W.F. Hegel (aesthetics) 1 | |
| A reaction: I'm beginning to see that art is a wonderful focus and test case for political attitudes. Roughly, liberalism focuses on individual responses, but more societal views (from right and left) see it in terms of role in the community. Which are you? |
| 20394 | The purpose of art is to reveal to Spirit its own nature [Hegel, by Davies,S] |
| Full Idea: According to Hegel, the goal of art was to serve as a phase in a process by which Spirit would come to understand its own nature. | |
| From: report of Georg W.F.Hegel (Lectures on Aesthetics [1826]) by Stephen Davies - The Philosophy of Art (2nd ed) 2.7 | |
| A reaction: I try very hard to understand ideas like this. Really really hard. However, since I see little sign of 'Spirit' really understanding its own nature, I'm guessing that the project is not going well. |
| 21794 | The main purpose of art is to express the unity of human life [Hegel] |
| Full Idea: Art's primary function, for Hegel, is to give expression to the unity and wholeness of life - especially human life - that the contingencies of everyday existence frequently conceal. | |
| From: Georg W.F.Hegel (Lectures on Aesthetics [1826]), quoted by Stephen Houlgate - An Introduction to Hegel 09 'Beauty' | |
| A reaction: I don't find the view that human life is 'unified' and 'whole' vary illuminating, and I have no objection to art which reflects the fragmentary and unstable aspects of life. I suspect Hegel would just prefer it if life were a unity. |
| 20415 | Art forms a bridge between the sensuous world and the world of pure thought [Hegel] |
| Full Idea: Spirit generates out of itself works of fine art as the first reconciling middle term between pure thought and what is merely external, sensuous and transient - between finite natural reality and the infinite freedom of conceptual thinking. | |
| From: Georg W.F.Hegel (Lectures on Aesthetics [1826], p.8), quoted by Richard Eldridge - G.W.F. Hegel (aesthetics) | |
| A reaction: This apparently says that there is necessarily an intellectual and conceptual component in art. This means little to me. Does he include portraits? Dutch domestic scenes? Would photography qualify? |