35 ideas
| 20962 | Habermas seems to make philosophy more democratic [Habermas, by Bowie] |
| Full Idea: Habermas is concerned to avoid the traumas of modern German history by making democracy an integral part of philosophy. | |
| From: report of Jürgen Habermas (The Theory of Communicative Action [1981]) by Andrew Bowie - Introduction to German Philosophy Conc 'Habermas' | |
| A reaction: Hence Habermas's emphasis on communication as central to language, which is central to philosophy. Modern philosophy departments are amazingly hierarchical. |
| 15670 | The aim of 'post-metaphysical' philosophy is to interpret the sciences [Habermas, by Finlayson] |
| Full Idea: For Habermas, the task of what he calls 'post-metaphysical' philosophy is to be a stand-in and interpreter for the specialized sciences. | |
| From: report of Jürgen Habermas (The Theory of Communicative Action [1981]) by James Gordon Finlayson - Habermas Ch.5:65 |
| 15665 | We can do social philosophy by studying coordinated action through language use [Habermas, by Finlayson] |
| Full Idea: Habermas claims to have embarked upon a new way of doing social philosophy, one that begins from an analysis of language use and that locates the rational basis of the coordination of action in speech. | |
| From: report of Jürgen Habermas (The Theory of Communicative Action [1981]) by James Gordon Finlayson - Habermas Ch.3:28 |
| 20573 | Rather than instrumental reason, Habermas emphasises its communicative role [Habermas, by Oksala] |
| Full Idea: Instead of Enlightenment instrumental rationality (criticised by Adorno and Horkheimer), Habermas emphasizes 'communicative rationality', which makes critical discussion and mutual understanding possible. | |
| From: report of Jürgen Habermas (The Theory of Communicative Action [1981]) by Johanna Oksala - Political Philosophy: all that matters Ch.6 | |
| A reaction: There was a good reason not to smoke cigarettes, before we found out what it is. In one sense, reasons are in the world. This is interesting, but I feel analytic vertigo, as the lovely concept of 'rationality' becomes blurred and diffused. |
| 17926 | Rejecting double negation elimination undermines reductio proofs [Colyvan] |
| Full Idea: The intuitionist rejection of double negation elimination undermines the important reductio ad absurdum proof in classical mathematics. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 1.1.3) |
| 17925 | Showing a disproof is impossible is not a proof, so don't eliminate double negation [Colyvan] |
| Full Idea: In intuitionist logic double negation elimination fails. After all, proving that there is no proof that there can't be a proof of S is not the same thing as having a proof of S. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 1.1.3) | |
| A reaction: I do like people like Colyvan who explain things clearly. All of this difficult stuff is understandable, if only someone makes the effort to explain it properly. |
| 17924 | Excluded middle says P or not-P; bivalence says P is either true or false [Colyvan] |
| Full Idea: The law of excluded middle (for every proposition P, either P or not-P) must be carefully distinguished from its semantic counterpart bivalence, that every proposition is either true or false. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 1.1.3) | |
| A reaction: So excluded middle makes no reference to the actual truth or falsity of P. It merely says P excludes not-P, and vice versa. |
| 17929 | Löwenheim proved his result for a first-order sentence, and Skolem generalised it [Colyvan] |
| Full Idea: Löwenheim proved that if a first-order sentence has a model at all, it has a countable model. ...Skolem generalised this result to systems of first-order sentences. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 2.1.2) |
| 17930 | Axioms are 'categorical' if all of their models are isomorphic [Colyvan] |
| Full Idea: A set of axioms is said to be 'categorical' if all models of the axioms in question are isomorphic. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 2.1.2) | |
| A reaction: The best example is the Peano Axioms, which are 'true up to isomorphism'. Set theory axioms are only 'quasi-isomorphic'. |
| 17928 | Ordinal numbers represent order relations [Colyvan] |
| Full Idea: Ordinal numbers represent order relations. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 1.2.3 n17) |
| 17923 | Intuitionists only accept a few safe infinities [Colyvan] |
| Full Idea: For intuitionists, all but the smallest, most well-behaved infinities are rejected. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 1.1.3) | |
| A reaction: The intuitionist idea is to only accept what can be clearly constructed or proved. |
| 17941 | Infinitesimals were sometimes zero, and sometimes close to zero [Colyvan] |
| Full Idea: The problem with infinitesimals is that in some places they behaved like real numbers close to zero but in other places they behaved like zero. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 7.1.2) | |
| A reaction: Colyvan gives an example, of differentiating a polynomial. |
| 17922 | Reducing real numbers to rationals suggested arithmetic as the foundation of maths [Colyvan] |
| Full Idea: Given Dedekind's reduction of real numbers to sequences of rational numbers, and other known reductions in mathematics, it was tempting to see basic arithmetic as the foundation of mathematics. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 1.1.1) | |
| A reaction: The reduction is the famous Dedekind 'cut'. Nowadays theorists seem to be more abstract (Category Theory, for example) instead of reductionist. |
| 13007 | Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz] |
| Full Idea: Archimedes gave a sort of definition of 'straight line' when he said it is the shortest line between two points. | |
| From: report of Archimedes (fragments/reports [c.240 BCE]) by Gottfried Leibniz - New Essays on Human Understanding 4.13 | |
| A reaction: Commentators observe that this reduces the purity of the original Euclidean axioms, because it involves distance and measurement, which are absent from the purest geometry. |
| 17936 | Transfinite induction moves from all cases, up to the limit ordinal [Colyvan] |
| Full Idea: Transfinite inductions are inductive proofs that include an extra step to show that if the statement holds for all cases less than some limit ordinal, the statement also holds for the limit ordinal. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 5.2.1 n11) |
| 17940 | Most mathematical proofs are using set theory, but without saying so [Colyvan] |
| Full Idea: Most mathematical proofs, outside of set theory, do not explicitly state the set theory being employed. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 7.1.1) |
| 17931 | Structuralism say only 'up to isomorphism' matters because that is all there is to it [Colyvan] |
| Full Idea: Structuralism is able to explain why mathematicians are typically only interested in describing the objects they study up to isomorphism - for that is all there is to describe. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 3.1.2) |
| 17932 | If 'in re' structures relies on the world, does the world contain rich enough structures? [Colyvan] |
| Full Idea: In re structuralism does not posit anything other than the kinds of structures that are in fact found in the world. ...The problem is that the world may not provide rich enough structures for the mathematics. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 3.1.2) | |
| A reaction: You can perceive a repeating pattern in the world, without any interest in how far the repetitions extend. |
| 20961 | What is considered a priori changes as language changes [Habermas, by Bowie] |
| Full Idea: Habermas claims that what is regarded as a priori changes with history. This is because the linguistic structures on which judgements depend are themselves part of history, not prior to it. | |
| From: report of Jürgen Habermas (The Theory of Communicative Action [1981]) by Andrew Bowie - Introduction to German Philosophy Conc 'Habermas' | |
| A reaction: This is an interesting style of argument generally only found in continental philosophers, because they see the problem as historical rather than timeless. Compare Idea 20595, which sees analyticity historically. |
| 17943 | Probability supports Bayesianism better as degrees of belief than as ratios of frequencies [Colyvan] |
| Full Idea: Those who see probabilities as ratios of frequencies can't use Bayes's Theorem if there is no objective prior probability. Those who accept prior probabilities tend to opt for a subjectivist account, where probabilities are degrees of belief. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 9.1.8) | |
| A reaction: [compressed] |
| 17939 | Mathematics can reveal structural similarities in diverse systems [Colyvan] |
| Full Idea: Mathematics can demonstrate structural similarities between systems (e.g. missing population periods and the gaps in the rings of Saturn). | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 6.3.2) | |
| A reaction: [Colyvan expounds the details of his two examples] It is these sorts of results that get people enthusiastic about the mathematics embedded in nature. A misunderstanding, I think. |
| 17938 | Mathematics can show why some surprising events have to occur [Colyvan] |
| Full Idea: Mathematics can show that under a broad range of conditions, something initially surprising must occur (e.g. the hexagonal structure of honeycomb). | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 6.3.2) |
| 17934 | Proof by cases (by 'exhaustion') is said to be unexplanatory [Colyvan] |
| Full Idea: Another style of proof often cited as unexplanatory are brute-force methods such as proof by cases (or proof by exhaustion). | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 5.2.1) |
| 17933 | Reductio proofs do not seem to be very explanatory [Colyvan] |
| Full Idea: One kind of proof that is thought to be unexplanatory is the 'reductio' proof. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 5.2.1) | |
| A reaction: Presumably you generate a contradiction, but are given no indication of why the contradiction has arisen? Tracking back might reveal the source of the problem? Colyvan thinks reductio can be explanatory. |
| 17935 | If inductive proofs hold because of the structure of natural numbers, they may explain theorems [Colyvan] |
| Full Idea: It might be argued that any proof by induction is revealing the explanation of the theorem, namely, that it holds by virtue of the structure of the natural numbers. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 5.2.1) | |
| A reaction: This is because induction characterises the natural numbers, in the Peano Axioms. |
| 17942 | Can a proof that no one understands (of the four-colour theorem) really be a proof? [Colyvan] |
| Full Idea: The proof of the four-colour theorem raises questions about whether a 'proof' that no one understands is a proof. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 9.1.6) | |
| A reaction: The point is that the theorem (that you can colour countries on a map with just four colours) was proved with the help of a computer. |
| 17937 | Mathematical generalisation is by extending a system, or by abstracting away from it [Colyvan] |
| Full Idea: One type of generalisation in mathematics extends a system to go beyond what is was originally set up for; another kind involves abstracting away from some details in order to capture similarities between different systems. | |
| From: Mark Colyvan (Introduction to the Philosophy of Mathematics [2012], 5.2.2) |
| 15667 | To understand a statement is to know what would make it acceptable [Habermas] |
| Full Idea: We understand the meaning of a speech act when we know what would make it acceptable. | |
| From: Jürgen Habermas (The Theory of Communicative Action [1981], I:297), quoted by James Gordon Finlayson - Habermas Ch.3:37 | |
| A reaction: Finlayson glosses this as requiring the reasons which would justify the speech act. |
| 15668 | Meaning is not fixed by a relation to the external world, but a relation to other speakers [Habermas, by Finlayson] |
| Full Idea: On Habermas's view, meanings are not determined by the speaker's relation to the external world, but by his relation to his interlocutors; meaning is essentially intersubjective. | |
| From: report of Jürgen Habermas (The Theory of Communicative Action [1981]) by James Gordon Finlayson - Habermas Ch.3:38 | |
| A reaction: This view is not the same as Grice's, but it is clearly much closer to Grice than to (say) the Frege/Davidson emphasis on truth-conditions. I'm not sure if I would know how to begin arbitrating between the two views! |
| 15666 | To understand language is to know how to use it to reach shared understandings [Habermas] |
| Full Idea: One simply would not know what it is to understand the meaning of a linguistic expression if one did not know how one could make use of it in order to reach understanding with someone about something. | |
| From: Jürgen Habermas (On the Pragmatics of Communications [1998], p.228), quoted by James Gordon Finlayson - Habermas Ch.3:34 | |
| A reaction: Not offered as a 'theory of meaning', and certainly plausible. Compare a hammer, though: a proper understanding is that it is used to exert a sharp force, but you can take in its structure and nature before you spot its usage. |
| 15677 | Moral right is linked to validity and truth, so morality is a matter of knowledge, not an expression of values [Habermas, by Finlayson] |
| Full Idea: According to discourse ethics moral rightness is internally linked to validity and is analogous to truth: ..thus Habermas takes himself to have shown that morality is a matter of knowledge, rather than the expression of contingently held values. | |
| From: report of Jürgen Habermas (Moral Consciousness and Communicative Action [1990]) by James Gordon Finlayson - Habermas Ch.7:102 | |
| A reaction: I can immediately hear Nietzsche asking why you place such a high value on knowledge. Personally I don't assume that values must be 'contingent'. The Aristotelian tradition sees necessary values in facts about human nature. |
| 15672 | Actions norms are only valid if everyone possibly affected is involved in the discourse [Habermas] |
| Full Idea: Only those action norms are valid to which all possibly affected persons could agree as participants in rational discourse. | |
| From: Jürgen Habermas (Between Facts and Norms [1996], p.107), quoted by James Gordon Finlayson - Habermas Ch.6:79 | |
| A reaction: This remark stands somewhere between Kant and Rawls. The Holocaust stands behind Habermas's philosophy. The thought, I suppose, is that it would never have happened if everybody had been fully involved in the original discourse about it. |
| 15671 | Move from individual willing of a general law, to willing norms agreed with other people [Habermas] |
| Full Idea: The emphasis shifts from what each can will without contradiction to be a general law, to what all can will in agreement to be a universal norm. | |
| From: Jürgen Habermas (Moral Consciousness and Communicative Action [1990], p.67), quoted by James Gordon Finlayson - Habermas Ch.5:69 | |
| A reaction: This strikes me as being very close to Scanlon's contractualism. As expressed here, it sounds more vulnerable than Kant's full universality to the problem of Nazis agreeing odious universal norms. Habermas calls it 'discourse ethics'. |
| 15669 | People endorse equality, universality and inclusiveness, just by their communicative practices [Habermas, by Finlayson] |
| Full Idea: The ideal of equality, universality, and inclusiveness are inscribed in the communicative practices of the lifeworld, and agents, merely by virtue of communicating, conform to them. | |
| From: report of Jürgen Habermas (The Theory of Communicative Action [1981]) by James Gordon Finlayson - Habermas Ch.4:60 | |
| A reaction: This summary of Habermas's social views strikes me as thoroughly Kantian. It is something like the ideals of the Kingdom of Ends, necessarily implemented in a liberal society. Habermas emphasises the social, where Kant starts from the liberal. |
| 23416 | Political involvement is needed, to challenge existing practices [Habermas, by Kymlicka] |
| Full Idea: Habermas thinks political deliberation is required precisely because in its absence people will tend to accept existing practices as given, and thereby perpetuate false needs. | |
| From: report of Jürgen Habermas (The Theory of Communicative Action [1981]) by Will Kymlicka - Community 'need' | |
| A reaction: If the dream is healthy and intelligent progress, it is not clear where that should come from. The problem with state involvement in the authority and power of the state. Locals are often prejudiced, so the intermediate level may be best. |