20 ideas
| 7662 | Romanticism is the greatest change in the consciousness of the West [Berlin] |
| Full Idea: Romanticism seems to me the greatest single shift in the consciousness of the West that has occurred. | |
| From: Isaiah Berlin (The Roots of Romanticism [1965], Ch.1) | |
| A reaction: Far be it from me to challenge Berlin on such things, but I think that the scientific revolution of the seventeenth century (though acting more slowly and less dramatically than romanticism) may well be more significant in the long run. Ideas filter down. |
| 13838 | 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. |
| 13833 | '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. |
| 13834 | 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). |
| 13835 | 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) |
| 13845 | 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? |
| 13840 | 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) |
| 13844 | 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. |
| 13842 | 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) |
| 13837 | 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. |
| 13839 | 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... |
| 13843 | 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. |
| 8510 | 'Socrates is wise' means a concurrence sum contains a member of a similarity set [Williams,DC] |
| Full Idea: 'Socrates is wise' means that the concurrence sum (Socrates) includes a trope which is a member of the similarity set (Wisdom). | |
| From: Donald C. Williams (On the Elements of Being: I [1953], p.119) | |
| A reaction: Resemblance has to be taken as a basic (and presumably unanalysable) concept, which invites Russell's objection (Idea 4441). |
| 8508 | A 'trope' is an abstract particular, the occurrence of an essence [Williams,DC] |
| Full Idea: I shall divert the word 'trope' to stand for the abstract particular which is, so to speak, the occurrence of an essence. | |
| From: Donald C. Williams (On the Elements of Being: I [1953], p.115) | |
| A reaction: Thus tropes entered philosophical discussion. Presumably the precedent for an 'abstract particular' would be a particular occurrence of the number 7. |
| 8509 | A world is completely constituted by its tropes and their connections [Williams,DC] |
| Full Idea: Any possible world, and hence, of course, this one, is completely constituted by its tropes and connections of location and similarity. | |
| From: Donald C. Williams (On the Elements of Being: I [1953], p.116) | |
| A reaction: Note that Williams regularly referred to possible worlds in 1953. This is a full-blooded trope theory, which asserts that objects are bundles of tropes, so that both particulars and universals are ontologically taken care of. |
| 7665 | Most Enlightenment thinkers believed that virtue consists ultimately in knowledge [Berlin] |
| Full Idea: What is common to most of the main thinker of the Enlightenment is the view that virtue consists ultimately in knowledge. | |
| From: Isaiah Berlin (The Roots of Romanticism [1965], Ch.2) | |
| A reaction: I have always found this view (which seems to originate with Socrates) rather sympathetic. What is so frustrating about cheerful optimists who smoke cigarettes is not the weakness of will or strong desires, but their apparent failure of understanding. |
| 7676 | If we are essentially free wills, authenticity and sincerity are the highest virtues [Berlin] |
| Full Idea: Since (for romantics) we are wills, and we must be free, in the Kantian sense, controllable motives count more than consequences, and the greatest virtue of all is what existentialists call 'authenticity' and what romantics called 'sincerity'. | |
| From: Isaiah Berlin (The Roots of Romanticism [1965], Ch.6) | |
| A reaction: The case of the sincere or authentic Nazi shows the problems with this. However, I agree that sincerity is a key virtue, perhaps the crucial preliminary to all the other virtues. It is hard to imagine a flow of other virtues from an insincere person. |
| 7664 | The Greeks have no notion of obligation or duty [Berlin] |
| Full Idea: There is an absence among the Greeks of a notion of obligation, and hence of duty, which is difficult to grasp for people who read the Greeks through spectacles partly affected by the jews. | |
| From: Isaiah Berlin (The Roots of Romanticism [1965], Ch.1) | |
| A reaction: This doesn't quite fit early section of 'Republic', in which morality is a mutual agreement not to do harm. Presumably the Greek word 'deon' refers to what needs to be done, rather than to anyone's obligation to do it(?). Contracts need duty? Cf. 4133 |
| 7677 | Central to existentialism is the romantic idea that there is nothing to lean on [Berlin] |
| Full Idea: The central sermon of existentialism is essentially a romantic one, namely, that there is in the world nothing to lean on. | |
| From: Isaiah Berlin (The Roots of Romanticism [1965], Ch.6) | |
| A reaction: He tracks this back to Kant's view that our knowledge of the world arises out of our own minds. So what is there to lean on? Rational consistency? Natural human excellence? God? Pleasure? Anonymous duty? I like the second one. |
| 7663 | Judaism and Christianity views are based on paternal, family and tribal relations [Berlin] |
| Full Idea: The notion from which both Judaism and Christianity to a large degree sprang is the notion of family life, the relations of father and son, perhaps the relations of members of a tribe to one another. | |
| From: Isaiah Berlin (The Roots of Romanticism [1965], Ch.1) | |
| A reaction: He compares this with Plato's mathematical view of reality. Key stories would be Abraham and Isaac, and Jesus being the 'son' of God, which both touch the killing of the child. Berlin means that the universe is explained this way. |