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All the ideas for 'What is Logic?st1=Ian Hacking', 'Science and Hypothesis' and 'A Philosophy of Boredom'

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23 ideas

1. Philosophy / B. History of Ideas / 5. Later European Thought
Modern Western culture suddenly appeared in Jena in the 1790s [Svendsen]
     Full Idea: Foucault was right to say that Jena in the 1790s was the arena where the fundamental interests in modern Western culture suddenly had their breakthrough.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.2)
     A reaction: [Hölderlin, Novalis, Tieck, Schlegel, based on Kant and Fichte] Romanticism seems to have been born then. Is that the essence of modernism? Foucault and his pals are hoping to destroy the Enlightenment by ignoring it, but that is modern too.
1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
You can't understand love in terms of 'if and only if...' [Svendsen]
     Full Idea: I once began reading a philosophical article on love. The following statement soon came up: 'Bob loves Kate if and only if...' At that point I stopped reading. Such a formalized approach was unsuitable, because the actual phenomenon would be lost.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Pref)
     A reaction: It is hard to disagree! However, if your best friend comes to you and says, 'I can't decide whether I am really in love with Kate; what do you think?', how are you going to respond. You offer 'if and only if..', but in a warm and sympathetic way!
2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
     Full Idea: Today we expect that anything worth calling a definition should imply a semantics.
     From: Ian Hacking (What is Logic? [1979], §10)
     A reaction: He compares this with Gentzen 1935, who was attempting purely syntactic definitions of the logical connectives.
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
     Full Idea: 'Dilution' (or 'Thinning') provides an essential contrast between deductive and inductive reasoning; for the introduction of new premises may spoil an inductive inference.
     From: Ian Hacking (What is Logic? [1979], §06.2)
     A reaction: That is, inductive logic (if there is such a thing) is clearly non-monotonic, whereas classical inductive logic is monotonic.
Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
     Full Idea: If A |- B and B |- C, then A |- C. This generalises to: If Γ|-A,Θ and Γ,A |- Θ, then Γ |- Θ. Gentzen called this 'cut'. It is the transitivity of a deduction.
     From: Ian Hacking (What is Logic? [1979], §06.3)
     A reaction: I read the generalisation as 'If A can be either a premise or a conclusion, you can bypass it'. The first version is just transitivity (which by-passes the middle step).
Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking]
     Full Idea: Only the cut rule can have a conclusion that is less complex than its premises. Hence when cut is not used, a derivation is quite literally constructive, building up from components. Any theorem obtained by cut can be obtained without it.
     From: Ian Hacking (What is Logic? [1979], §08)
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
The various logics are abstractions made from terms like 'if...then' in English [Hacking]
     Full Idea: I don't believe English is by nature classical or intuitionistic etc. These are abstractions made by logicians. Logicians attend to numerous different objects that might be served by 'If...then', like material conditional, strict or relevant implication.
     From: Ian Hacking (What is Logic? [1979], §15)
     A reaction: The idea that they are 'abstractions' is close to my heart. Abstractions from what? Surely 'if...then' has a standard character when employed in normal conversation?
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
     Full Idea: First-order logic is the strongest complete compact theory with a Löwenheim-Skolem theorem.
     From: Ian Hacking (What is Logic? [1979], §13)
A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking]
     Full Idea: Henkin proved that there is no first-order treatment of branching quantifiers, which do not seem to involve any idea that is fundamentally different from ordinary quantification.
     From: Ian Hacking (What is Logic? [1979], §13)
     A reaction: See Hacking for an example of branching quantifiers. Hacking is impressed by this as a real limitation of the first-order logic which he generally favours.
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Second-order completeness seems to need intensional entities and possible worlds [Hacking]
     Full Idea: Second-order logic has no chance of a completeness theorem unless one ventures into intensional entities and possible worlds.
     From: Ian Hacking (What is Logic? [1979], §13)
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking]
     Full Idea: My doctrine is that the peculiarity of the logical constants resides precisely in that given a certain pure notion of truth and consequence, all the desirable semantic properties of the constants are determined by their syntactic properties.
     From: Ian Hacking (What is Logic? [1979], §09)
     A reaction: He opposes this to Peacocke 1976, who claims that the logical connectives are essentially semantic in character, concerned with the preservation of truth.
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking]
     Full Idea: For some purposes the variables of first-order logic can be regarded as prepositions and place-holders that could in principle be dispensed with, say by a system of arrows indicating what places fall in the scope of which quantifier.
     From: Ian Hacking (What is Logic? [1979], §11)
     A reaction: I tend to think of variables as either pronouns, or as definite descriptions, or as temporary names, but not as prepositions. Must address this new idea...
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
     Full Idea: A Löwenheim-Skolem theorem holds for anything which, on my delineation, is a logic.
     From: Ian Hacking (What is Logic? [1979], §13)
     A reaction: I take this to be an unusually conservative view. Shapiro is the chap who can give you an alternative view of these things, or Boolos.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Mathematicians do not study objects, but relations between objects [Poincaré]
     Full Idea: Mathematicians do not study objects, but relations between objects; it is a matter of indifference if the objects are replaced by others, provided the relations do not change. They are interested in form alone, not matter.
     From: Henri Poincaré (Science and Hypothesis [1902], p.20), quoted by E Reck / M Price - Structures and Structuralism in Phil of Maths §6
     A reaction: This connects modern structuralism with Aritotle's interest in the 'form' of things. Contrary to the views of the likes of Frege, it is hard to see that the number '7' has any properties at all, apart from its relations. A daffodil would do just as well.
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / e. Primary/secondary critique
If subjective and objective begin to merge, then so do primary and secondary qualities [Svendsen]
     Full Idea: It is doubtful whether the traditional dichotomy between the strictly subjective and the strictly objective can still be maintained; if not, we must also revise the distinction between primary and secondary qualities.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.3)
     A reaction: Very perceptive. The reason why I am so keen to hang onto the primary/secondary distinction is because I want to preserve objectivity (and realism). I much prefer Locke to Hume, as empiricist spokesmen.
18. Thought / A. Modes of Thought / 3. Emotions / b. Types of emotion
Emotions have intentional objects, while a mood is objectless [Svendsen]
     Full Idea: An emotion normally has an intentional object, while a mood is objectless.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.3)
     A reaction: It doesn't follow that the object of the emotion is clearly understood, or even that it is conscious. One may experience rising anger while struggling to see what its object is. Artistic symbolism seems to involve objects that create moods.
22. Metaethics / B. Value / 2. Values / e. Death
Death appears to be more frightening the less one has lived [Svendsen]
     Full Idea: Death appears to be more frightening the less one has lived.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.2)
     A reaction: [He credits Adorno with this] A good thought, which should be immediately emailed to Epicurus for comment. Which is worse - to die when you have barely started your great work (Ramsey), or dying in full flow (Schubert)?
23. Ethics / F. Existentialism / 4. Boredom
Boredom is so radical that suicide could not overcome it; only never having existed would do it [Svendsen]
     Full Idea: Boredom is so radical that it cannot even be overcome by suicide, only by something completely impossible - not to have existed at all.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.1)
     A reaction: [he cites Fernando Pessoa for this] The actor George Sanders left a suicide note saying that he was just bored. A cloud of boredom is left hanging in the air where he was.
We are bored because everything comes to us fully encoded, and we want personal meaning [Svendsen]
     Full Idea: Boredom results from a lack of personal meaning, which is due to the fact that all objects and actions come to us fully encoded, while we (as descendants of Romanticism) insist on a personal meaning.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.2)
     A reaction: This idea justifies me categorising Boredom under Existentialism. This is an excellent idea, and perfectly captures the experience of most teenagers, for whom it is impossible to impose a personal meaning on such a vast cultural reality.
The profoundest boredom is boredom with boredom [Svendsen]
     Full Idea: In the profound form of boredom, I am bored by boredom itself.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.3)
     A reaction: Boredom is boring, which is why I try to avoid it. Third-level boredom is a rather enchanting idea. It sounds remarkably similar to the Buddha experiencing enlightenment.
We can be unaware that we are bored [Svendsen]
     Full Idea: It is perfectly possible to be bored without being aware of the fact.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.1)
     A reaction: True. Also, I sometimes mistake indecision for boredom. It becomes very hard to say for certain whether you are bored. I am certain that I am bored if I am forced to do something which has no interest for me. The big one is free-but-bored.
24. Political Theory / B. Nature of a State / 1. Purpose of a State
We have achieved a sort of utopia, and it is boring, so that is the end of utopias [Svendsen]
     Full Idea: There can hardly be any new utopias. To the extent that we can imagine a utopia, it must already have been realised. A utopia cannot, by definition, include boredom, but the 'utopia' we are living in is boring.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.4)
     A reaction: Compare Idea 8989. Lots of people (including me) think that we have achieved a kind of liberal, democratic, individualistic 'utopia', but the community needs of people are not being met, so we still have a way to go.
24. Political Theory / D. Ideologies / 9. Communism
The concept of 'alienation' seems no longer applicable [Svendsen]
     Full Idea: I do not believe that the concept of 'alienation' is all that applicable any more.
     From: Lars Svendsen (A Philosophy of Boredom [2005], Ch.1)
     A reaction: Interesting but puzzling. If alienation is the key existential phenomenon of a capitalist society, why should it fade away if we remain capitalist? He is proposing that it has metamorphosed into boredom, which may be a different sort of alienation.