100 ideas
| 15586 | When philosophy makes itself intelligible, it commits suicide [Heidegger] |
| Full Idea: When philosophy makes itself intelligible, it commits suicide. | |
| From: Martin Heidegger (Contributions of Philosophy (On Appropriation) [1938], §259), quoted by Richard Polt - Heidegger: an introduction 5 'Contributions' | |
| A reaction: Polt describes this remark as 'theatrical', but it seems to speak for itself! |
| 15585 | Later Heidegger sees philosophy as more like poetry than like science [Heidegger, by Polt] |
| Full Idea: In his later work Heidegger came to view philosophy as closer to poetry than to science. | |
| From: report of Martin Heidegger (The Origin of the Work of Art [1935], p.178) by Richard Polt - Heidegger: an introduction 5 'Signs' |
| 15582 | Perhaps the aim of philosophy is to abolish sham problems [Heidegger] |
| Full Idea: Perhaps it is precisely the task of philosophical investigation ultimately to deprive many problems of their sham existence. | |
| From: Martin Heidegger (History of the Concept of Time [1925], p.162), quoted by Richard Polt - Heidegger: an introduction 3.§43-44 | |
| A reaction: Polt notes how very Wittgensteinian this remark is. I take this to be a very minor task of philosophy. The main task is to address the real problems. It's amazing how many people love this sort of remark. I wonder why? |
| 22223 | Being-in-the-world is projection to possibilities, thrownness among them, and fallenness within them [Heidegger, by Caputo] |
| Full Idea: Being-in-the-world is a phenomenon of 'care' with a tripartite structure: a) projection towards its possibilities, b) thrownness among those possibilities, so Dasein is not free, and c) fallenness among worldly possibilities, to neglect of its own. | |
| From: report of Martin Heidegger (Being and Time [1927]) by John D. Caputo - Heidegger p.227 | |
| A reaction: Sounds a bit Californian to me. Just living among the world's possibilities is evidently a bad thing, because you could be concentrating on yourself and your own development instead? |
| 22158 | Pheomenology seeks things themselves, without empty theories, problems and concepts [Heidegger] |
| Full Idea: 'Phenomenology' can be formulated as 'To the things themselves!' It is opposed to all free-floating constructions and accidental findings, and to conceptions which only seem to have been demonstrated. It is opposed to traditiona' pseudo-problems. | |
| From: Martin Heidegger (Being and Time [1927], Intro II.07) | |
| A reaction: It sounds as if we are invited to look at the world the way a dog might look at it. I am not at all clear what it to be gained from this approach. |
| 15574 | 'Logos' really means 'making something manifest' [Heidegger, by Polt] |
| Full Idea: Heidegger concludes that 'logos' essentially means 'making something manifest'. | |
| From: report of Martin Heidegger (Being and Time [1927], 56/33) by Richard Polt - Heidegger: an introduction 3.§7 | |
| A reaction: It would at least seem to involve revealing the truth of something, though truth doesn't seem to be central to Heidegger's thought. 'Logos' is often translated as 'an account', as well as a 'reason', so Heidegger may be right. |
| 21953 | For Heidegger there is 'ontic' truth or 'uncoveredness', as in "he is a true friend" [Heidegger, by Wrathall] |
| Full Idea: We say things like 'he is a true friend'. Heidegger calls this kind of truth 'ontic truth' or the 'uncoveredness' of entities. | |
| From: report of Martin Heidegger (On the Essence of Truth [1935]) by Mark Wrathall - Heidegger: how to read 7 | |
| A reaction: [In his later essays] The example is very bad for showing a clear alternative meaning of 'true'. I presume it can only be explained in essentialist terms - an entity is 'true' if its appearance and behaviour conforms to its essence. |
| 15569 | Heidegger says truth is historical, and never absolute [Heidegger, by Polt] |
| Full Idea: Heidegger is a relentless enemy of ahistorical, absolutist concepts of truth. | |
| From: report of Martin Heidegger (Being and Time [1927]) by Richard Polt - Heidegger: an introduction 1 | |
| A reaction: I presume that if truth is not absolute then it must be relative, but Polt is a little coy about saying so. For me, anyone who says truth is relative doesn't understand the concept, and is talking about something else. |
| 9535 | 'Contradictory' propositions always differ in truth-value [Lemmon] |
| Full Idea: Two propositions are 'contradictory' if they are never both true and never both false either, which means that ¬(A↔B) is a tautology. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9509 | That proposition that both P and Q is their 'conjunction', written P∧Q [Lemmon] |
| Full Idea: If P and Q are any two propositions, the proposition that both P and Q is called the 'conjunction' of P and Q, and is written P∧Q. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.3) | |
| A reaction: [I use the more fashionable inverted-v '∧', rather than Lemmon's '&', which no longer seems to be used] P∧Q can also be defined as ¬(¬P∨¬Q) |
| 9508 | The sign |- may be read as 'therefore' [Lemmon] |
| Full Idea: I introduce the sign |- to mean 'we may validly conclude'. To call it the 'assertion sign' is misleading. It may conveniently be read as 'therefore'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.2) | |
| A reaction: [Actually no gap between the vertical and horizontal strokes of the sign] As well as meaning 'assertion', it may also mean 'it is a theorem that' (with no proof shown). |
| 9511 | We write the conditional 'if P (antecedent) then Q (consequent)' as P→Q [Lemmon] |
| Full Idea: We write 'if P then Q' as P→Q. This is called a 'conditional', with P as its 'antecedent', and Q as its 'consequent'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.2) | |
| A reaction: P→Q can also be written as ¬P∨Q. |
| 9510 | That proposition that either P or Q is their 'disjunction', written P∨Q [Lemmon] |
| Full Idea: If P and Q are any two propositions, the proposition that either P or Q is called the 'disjunction' of P and Q, and is written P∨Q. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.3) | |
| A reaction: This is inclusive-or (meaning 'P, or Q, or both'), and not exlusive-or (Boolean XOR), which means 'P, or Q, but not both'. The ∨ sign is sometimes called 'vel' (Latin). |
| 9512 | We write the 'negation' of P (not-P) as ¬ [Lemmon] |
| Full Idea: We write 'not-P' as ¬P. This is called the 'negation' of P. The 'double negation' of P (not not-P) would be written as ¬¬P. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.2) | |
| A reaction: Lemmons use of -P is no longer in use for 'not'. A tilde sign (squiggle) is also used for 'not', but some interpreters give that a subtly different meaning (involving vagueness). The sign ¬ is sometimes called 'hook' or 'corner'. |
| 9513 | We write 'P if and only if Q' as P↔Q; it is also P iff Q, or (P→Q)∧(Q→P) [Lemmon] |
| Full Idea: We write 'P if and only if Q' as P↔Q. It is called the 'biconditional', often abbreviate in writing as 'iff'. It also says that P is both sufficient and necessary for Q, and may be written out in full as (P→Q)∧(Q→P). | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.4) | |
| A reaction: If this symbol is found in a sequence, the first move in a proof is to expand it to the full version. |
| 9514 | If A and B are 'interderivable' from one another we may write A -||- B [Lemmon] |
| Full Idea: If we say that A and B are 'interderivable' from one another (that is, A |- B and B |- A), then we may write A -||- B. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9516 | A 'well-formed formula' follows the rules for variables, ¬, →, ∧, ∨, and ↔ [Lemmon] |
| Full Idea: A 'well-formed formula' of the propositional calculus is a sequence of symbols which follows the rules for variables, ¬, →, ∧, ∨, and ↔. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.1) |
| 9517 | The 'scope' of a connective is the connective, the linked formulae, and the brackets [Lemmon] |
| Full Idea: The 'scope' of a connective in a certain formula is the formulae linked by the connective, together with the connective itself and the (theoretically) encircling brackets | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.1) |
| 9519 | A 'substitution-instance' is a wff formed by consistent replacing variables with wffs [Lemmon] |
| Full Idea: A 'substitution-instance' is a wff which results by replacing one or more variables throughout with the same wffs (the same wff replacing each variable). | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9529 | A wff is 'inconsistent' if all assignments to variables result in the value F [Lemmon] |
| Full Idea: If a well-formed formula of propositional calculus takes the value F for all possible assignments of truth-values to its variables, it is said to be 'inconsistent'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9531 | 'Contrary' propositions are never both true, so that ¬(A∧B) is a tautology [Lemmon] |
| Full Idea: If A and B are expressible in propositional calculus notation, they are 'contrary' if they are never both true, which may be tested by the truth-table for ¬(A∧B), which is a tautology if they are contrary. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9534 | Two propositions are 'equivalent' if they mirror one another's truth-value [Lemmon] |
| Full Idea: Two propositions are 'equivalent' if whenever A is true B is true, and whenever B is true A is true, in which case A↔B is a tautology. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9530 | A wff is 'contingent' if produces at least one T and at least one F [Lemmon] |
| Full Idea: If a well-formed formula of propositional calculus takes at least one T and at least one F for all the assignments of truth-values to its variables, it is said to be 'contingent'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9532 | 'Subcontrary' propositions are never both false, so that A∨B is a tautology [Lemmon] |
| Full Idea: If A and B are expressible in propositional calculus notation, they are 'subcontrary' if they are never both false, which may be tested by the truth-table for A∨B, which is a tautology if they are subcontrary. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9533 | A 'implies' B if B is true whenever A is true (so that A→B is tautologous) [Lemmon] |
| Full Idea: One proposition A 'implies' a proposition B if whenever A is true B is true (but not necessarily conversely), which is only the case if A→B is tautologous. Hence B 'is implied' by A. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9528 | A wff is a 'tautology' if all assignments to variables result in the value T [Lemmon] |
| Full Idea: If a well-formed formula of propositional calculus takes the value T for all possible assignments of truth-values to its variables, it is said to be a 'tautology'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.3) |
| 9518 | A 'theorem' is the conclusion of a provable sequent with zero assumptions [Lemmon] |
| Full Idea: A 'theorem' of logic is the conclusion of a provable sequent in which the number of assumptions is zero. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) | |
| A reaction: This is what Quine and others call a 'logical truth'. |
| 9401 | ∨E: Derive C from A∨B, if C can be derived both from A and from B [Lemmon] |
| Full Idea: Or-Elimination (∨E): Given A∨B, we may derive C if it is proved from A as assumption and from B as assumption. This will also depend on prior assumptions. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9396 | DN: Given A, we may derive ¬¬A [Lemmon] |
| Full Idea: Double Negation (DN): Given A, we may derive ¬¬A as a conclusion, and vice versa. The conclusion depends on the assumptions of the premiss. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9393 | A: we may assume any proposition at any stage [Lemmon] |
| Full Idea: Assumptions (A): any proposition may be introduced at any stage of a proof. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9399 | ∧E: Given A∧B, we may derive either A or B separately [Lemmon] |
| Full Idea: And-Elimination (∧E): Given A∧B, we may derive either A or B separately. The conclusions will depend on the assumptions of the premiss. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9398 | ∧I: Given A and B, we may derive A∧B [Lemmon] |
| Full Idea: And-Introduction (&I): Given A and B, we may derive A∧B as conclusion. This depends on their previous assumptions. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9397 | CP: Given a proof of B from A as assumption, we may derive A→B [Lemmon] |
| Full Idea: Conditional Proof (CP): Given a proof of B from A as assumption, we may derive A→B as conclusion, on the remaining assumptions (if any). | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9394 | MPP: Given A and A→B, we may derive B [Lemmon] |
| Full Idea: Modus Ponendo Ponens (MPP): Given A and A→B, we may derive B as a conclusion. B will rest on any assumptions that have been made. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9402 | RAA: If assuming A will prove B∧¬B, then derive ¬A [Lemmon] |
| Full Idea: Reduction ad Absurdum (RAA): Given a proof of B∧¬B from A as assumption, we may derive ¬A as conclusion, depending on the remaining assumptions (if any). | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9395 | MTT: Given ¬B and A→B, we derive ¬A [Lemmon] |
| Full Idea: Modus Tollendo Tollens (MTT): Given ¬B and A→B, we derive ¬A as a conclusion. ¬A depends on any assumptions that have been made | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9400 | ∨I: Given either A or B separately, we may derive A∨B [Lemmon] |
| Full Idea: Or-Introduction (∨I): Given either A or B separately, we may derive A∨B as conclusion. This depends on the assumption of the premisses. | |
| From: E.J. Lemmon (Beginning Logic [1965], 1.5) |
| 9521 | 'Modus tollendo ponens' (MTP) says ¬P, P ∨ Q |- Q [Lemmon] |
| Full Idea: 'Modus tollendo ponens' (MTP) says that if a disjunction holds and also the negation of one of its disjuncts, then the other disjunct holds. Thus ¬P, P ∨ Q |- Q may be introduced as a theorem. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) | |
| A reaction: Unlike Modus Ponens and Modus Tollens, this is a derived rule. |
| 9522 | 'Modus ponendo tollens' (MPT) says P, ¬(P ∧ Q) |- ¬Q [Lemmon] |
| Full Idea: 'Modus ponendo tollens' (MPT) says that if the negation of a conjunction holds and also one of its conjuncts, then the negation of the other conjunct holds. Thus P, ¬(P ∧ Q) |- ¬Q may be introduced as a theorem. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) | |
| A reaction: Unlike Modus Ponens and Modus Tollens, this is a derived rule. |
| 9525 | We can change conditionals into negated conjunctions with P→Q -||- ¬(P ∧ ¬Q) [Lemmon] |
| Full Idea: The proof that P→Q -||- ¬(P ∧ ¬Q) is useful for enabling us to change conditionals into negated conjunctions | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9524 | We can change conditionals into disjunctions with P→Q -||- ¬P ∨ Q [Lemmon] |
| Full Idea: The proof that P→Q -||- ¬P ∨ Q is useful for enabling us to change conditionals into disjunctions. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9523 | De Morgan's Laws make negated conjunctions/disjunctions into non-negated disjunctions/conjunctions [Lemmon] |
| Full Idea: The forms of De Morgan's Laws [P∨Q -||- ¬(¬P ∧ ¬Q); ¬(P∨Q) -||- ¬P ∧ ¬Q; ¬(P∧Q) -||- ¬P ∨ ¬Q); P∧Q -||- ¬(¬P∨¬Q)] transform negated conjunctions and disjunctions into non-negated disjunctions and conjunctions respectively. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9527 | The Distributive Laws can rearrange a pair of conjunctions or disjunctions [Lemmon] |
| Full Idea: The Distributive Laws say that P ∧ (Q∨R) -||- (P∧Q) ∨ (P∧R), and that P ∨ (Q∨R) -||- (P∨Q) ∧ (P∨R) | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9526 | We can change conjunctions into negated conditionals with P→Q -||- ¬(P → ¬Q) [Lemmon] |
| Full Idea: The proof that P∧Q -||- ¬(P → ¬Q) is useful for enabling us to change conjunctions into negated conditionals. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) |
| 9537 | Truth-tables are good for showing invalidity [Lemmon] |
| Full Idea: The truth-table approach enables us to show the invalidity of argument-patterns, as well as their validity. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.4) |
| 9538 | A truth-table test is entirely mechanical, but this won't work for more complex logic [Lemmon] |
| Full Idea: A truth-table test is entirely mechanical, ..and in propositional logic we can even generate proofs mechanically for tautological sequences, ..but this mechanical approach breaks down with predicate calculus, and proof-discovery is an imaginative process. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.5) |
| 9536 | If any of the nine rules of propositional logic are applied to tautologies, the result is a tautology [Lemmon] |
| Full Idea: If any application of the nine derivation rules of propositional logic is made on tautologous sequents, we have demonstrated that the result is always a tautologous sequent. Thus the system is consistent. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.4) | |
| A reaction: The term 'sound' tends to be used now, rather than 'consistent'. See Lemmon for the proofs of each of the nine rules. |
| 9539 | Propositional logic is complete, since all of its tautologous sequents are derivable [Lemmon] |
| Full Idea: A logical system is complete is all expressions of a specified kind are derivable in it. If we specify tautologous sequent-expressions, then propositional logic is complete, because we can show that all tautologous sequents are derivable. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.5) | |
| A reaction: [See Lemmon 2.5 for details of the proofs] |
| 13909 | Write '(∀x)(...)' to mean 'take any x: then...', and '(∃x)(...)' to mean 'there is an x such that....' [Lemmon] |
| Full Idea: Just as '(∀x)(...)' is to mean 'take any x: then....', so we write '(∃x)(...)' to mean 'there is an x such that....' | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.1) | |
| A reaction: [Actually Lemmon gives the universal quantifier symbol as '(x)', but the inverted A ('∀') seems to have replaced it these days] |
| 13902 | 'Gm' says m has property G, and 'Pmn' says m has relation P to n [Lemmon] |
| Full Idea: A predicate letter followed by one name expresses a property ('Gm'), and a predicate-letter followed by two names expresses a relation ('Pmn'). We could write 'Pmno' for a complex relation like betweenness. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.1) |
| 13911 | The 'symbols' are bracket, connective, term, variable, predicate letter, reverse-E [Lemmon] |
| Full Idea: I define a 'symbol' (of the predicate calculus) as either a bracket or a logical connective or a term or an individual variable or a predicate-letter or reverse-E (∃). | |
| From: E.J. Lemmon (Beginning Logic [1965], 4.1) |
| 13910 | Our notation uses 'predicate-letters' (for 'properties'), 'variables', 'proper names', 'connectives' and 'quantifiers' [Lemmon] |
| Full Idea: Quantifier-notation might be thus: first, render into sentences about 'properties', and use 'predicate-letters' for them; second, introduce 'variables'; third, introduce propositional logic 'connectives' and 'quantifiers'. Plus letters for 'proper names'. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.1) |
| 13904 | Universal Elimination (UE) lets us infer that an object has F, from all things having F [Lemmon] |
| Full Idea: Our rule of universal quantifier elimination (UE) lets us infer that any particular object has F from the premiss that all things have F. It is a natural extension of &E (and-elimination), as universal propositions generally affirm a complex conjunction. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.2) |
| 13906 | With finite named objects, we can generalise with &-Intro, but otherwise we need ∀-Intro [Lemmon] |
| Full Idea: If there are just three objects and each has F, then by an extension of &I we are sure everything has F. This is of no avail, however, if our universe is infinitely large or if not all objects have names. We need a new device, Universal Introduction, UI. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.2) |
| 13908 | UE all-to-one; UI one-to-all; EI arbitrary-to-one; EE proof-to-one [Lemmon] |
| Full Idea: Univ Elim UE - if everything is F, then something is F; Univ Intro UI - if an arbitrary thing is F, everything is F; Exist Intro EI - if an arbitrary thing is F, something is F; Exist Elim EE - if a proof needed an object, there is one. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.3) | |
| A reaction: [My summary of Lemmon's four main rules for predicate calculus] This is the natural deduction approach, of trying to present the logic entirely in terms of introduction and elimination rules. See Bostock on that. |
| 13901 | Predicate logic uses propositional connectives and variables, plus new introduction and elimination rules [Lemmon] |
| Full Idea: In predicate calculus we take over the propositional connectives and propositional variables - but we need additional rules for handling quantifiers: four rules, an introduction and elimination rule for the universal and existential quantifiers. | |
| From: E.J. Lemmon (Beginning Logic [1965]) | |
| A reaction: This is Lemmon's natural deduction approach (invented by Gentzen), which is largely built on introduction and elimination rules. |
| 13903 | Universal elimination if you start with the universal, introduction if you want to end with it [Lemmon] |
| Full Idea: The elimination rule for the universal quantifier concerns the use of a universal proposition as a premiss to establish some conclusion, whilst the introduction rule concerns what is required by way of a premiss for a universal proposition as conclusion. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.2) | |
| A reaction: So if you start with the universal, you need to eliminate it, and if you start without it you need to introduce it. |
| 13905 | If there is a finite domain and all objects have names, complex conjunctions can replace universal quantifiers [Lemmon] |
| Full Idea: If all objects in a given universe had names which we knew and there were only finitely many of them, then we could always replace a universal proposition about that universe by a complex conjunction. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.2) |
| 13900 | 'Some Frenchmen are generous' is rendered by (∃x)(Fx→Gx), and not with the conditional → [Lemmon] |
| Full Idea: It is a common mistake to render 'some Frenchmen are generous' by (∃x)(Fx→Gx) rather than the correct (∃x)(Fx&Gx). 'All Frenchmen are generous' is properly rendered by a conditional, and true if there are no Frenchmen. | |
| From: E.J. Lemmon (Beginning Logic [1965], 3.1) | |
| A reaction: The existential quantifier implies the existence of an x, but the universal quantifier does not. |
| 9520 | The paradoxes of material implication are P |- Q → P, and ¬P |- P → Q [Lemmon] |
| Full Idea: The paradoxes of material implication are P |- Q → P, and ¬P |- P → Q. That is, since Napoleon was French, then if the moon is blue then Napoleon was French; and since Napoleon was not Chinese, then if Napoleon was Chinese, the moon is blue. | |
| From: E.J. Lemmon (Beginning Logic [1965], 2.2) | |
| A reaction: This is why the symbol → does not really mean the 'if...then' of ordinary English. Russell named it 'material implication' to show that it was a distinctively logical operator. |
| 15571 | The idea of an atemporal realm of validity is as implausible as medieval theology [Heidegger] |
| Full Idea: The whole idea of an atemporal realm of validity is an invention that is no less doubtful than medieval speculation about angels. | |
| From: Martin Heidegger (Basic Problems of Phenomenology [1927], p.215), quoted by Richard Polt - Heidegger: an introduction 2 'Theory' | |
| A reaction: This seems to be flatly opposed to the view of Frege, and shows why continental philosophy has largely eschewed a study of logic. It is hard for a philosopher to pursue logic extensively without commitment to the Fregean Third Realm. |
| 21897 | Reducing being to the study of beings too readily accepts the modern scientific view [Heidegger, by May] |
| Full Idea: Continental philosophers, following Heidegger, see in the attempt to reduce the question of being to that of beings a symptom of an age that is too ready to accept the terms in which science conceives the world. | |
| From: report of Martin Heidegger (Being and Time [1927]) by Todd May - Gilles Deleuze 1.04 | |
| A reaction: Interesting. I take the idea that this is a failing of the modern age to be ridiculous, since I take it to be the key metaphysical move made by Aristotle. Neverthless, Aristotle is closely in tune with modern science. For 'beings', read 'objects'. |
| 15573 | For us, Being is constituted by awareness of other sorts of Being [Heidegger] |
| Full Idea: We are Dasein - the entity who possesses - as constitutive for its understanding of existence - an understanding of the Being of all entities of a character other than its own. | |
| From: Martin Heidegger (Being and Time [1927], 34/13), quoted by Richard Polt - Heidegger: an introduction 3.§4 | |
| A reaction: This seems to connect to the emerging 'externalist' view of mind that comes with the external view of content coming from Purnam's Twin Earth idea. |
| 9273 | Heidegger turns to 'Being' to affirm the uniqueness of humans in the world [Heidegger, by Gray] |
| Full Idea: Heidegger turns to 'Being' for the same reason that Christians turn to God - to affirm the unique place of humans in the world. | |
| From: report of Martin Heidegger (Being and Time [1927]) by John Gray - Straw Dogs 2.4 | |
| A reaction: This is the first remark I have encountered that makes sense of Heidegger's Being to me! It places Heidegger as a modernist philosopher, trying to grapple with the decline of religion. I'll stick with Bertrand Russell on that. |
| 22157 | Dasein is a mode of Being distinguished by concern for its own Being [Heidegger] |
| Full Idea: Dasein is an entity which does not just occur among other entities. Rather it is ontically distinguished by the fact that, in its very Being, that Being is an issue for it. | |
| From: Martin Heidegger (Being and Time [1927], Intro I.04) | |
| A reaction: How do you distinguish the Being of normal humans from the Being of someone in a deep coma, who has no existential issues? Has that Dasein ceased to be? Why does angst create a new mode of Being, but flying doesn't? |
| 8137 | Dasein is ahead of itself in the world, and alongside encountered entities [Heidegger] |
| Full Idea: The formal existential totality of Dasein's ontological structural whole is: the Being of Dasein means ahead-of-itself-Being-already-in-(the-world) as Being-alongside (entities encountered within-the-world). | |
| From: Martin Heidegger (Being and Time [1927], I.6 41) | |
| A reaction: If you find that thought really illuminating, you are probably on the wrong website. However, the thought that we exist 'ahead of ourselves' might be a fruitful line for existentialists to explore. |
| 21951 | In company with others one's Dasein dissolves, and even the others themselves dissolve [Heidegger] |
| Full Idea: This being-with-one-another dissolves one's own Dasein completely into the kind of being of 'the others', in such a way, indeed, that the others, as distinguishable and explicit, vanish more and more. | |
| From: Martin Heidegger (Being and Time [1927], p.164), quoted by Mark Wrathall - Heidegger: how to read 5 | |
| A reaction: He seems to be describing the psychology of someone who joins a small crowd which gradually increases in size. I take this relation to others to be the basic existential dilemma, of retaining individual authenticity within a community. |
| 20745 | 'Dasein' expresses not 'what' the entity is, but its being [Heidegger] |
| Full Idea: When we designate this entity with the term 'Dasein' we are expressing not its 'what' (as if it were a table, house, or tree) but its being. | |
| From: Martin Heidegger (Being and Time [1927], p.297), quoted by Kevin Aho - Existentialism: an introduction 2 'Phenomenology' | |
| A reaction: Presumably analytic discussions of persons try to be too objective. Heidegger is trying to capture the thought at the heart of Kierkegaard's existentialism. Objectivity and subjectivity are never in conflict. Is there really a different mode of existence? |
| 8134 | The word 'dasein' is used to mean 'the manner of Being which man possesses', and also the human creature [Heidegger, by Cooper,DE] |
| Full Idea: Heidegger borrows a common German word 'dasein', meaning 'being' or 'existence', to refer both to 'the manner of Being which... man... possesses', and to the creature which possesses it. | |
| From: report of Martin Heidegger (Being and Time [1927], p.32) by David E. Cooper - Heidegger Ch.3 | |
| A reaction: This just strikes me as an elementary ontological mistake. Because something has startling properties it doesn't follow that we have a different type of Being. Magnets don't have a different type of being from ordinary iron. |
| 8135 | 'Dasein' is Being which is laid claim to, and which matters to its owner [Heidegger, by Cooper,DE] |
| Full Idea: We each of us not only have Dasein (our kind of Being), but we can lay claim to it. Also the Dasein of a thing 'is an issue for it' - we care about the kinds of creatures we can make ourselves into. | |
| From: report of Martin Heidegger (Being and Time [1927], p.67) by David E. Cooper - Heidegger Ch.3 | |
| A reaction: Heidegger says other more puzzling things about Dasein. The second half of the idea is what makes Heidegger an existentialist, and an inspiration for Sartre. |
| 21948 | Dasein is being which can understand itself, and possess itself in a way allowing authenticity [Heidegger] |
| Full Idea: Dasein is an entity which, in its very being, comports itself understandingly towards that being. ...Mineness belongs to an existent Dasein, and belongs to it as the condition which makes authenticity and inauthenticity possible. | |
| From: Martin Heidegger (Being and Time [1927], p.78), quoted by Mark Wrathall - Heidegger: how to read 1 | |
| A reaction: He might eventually persuade me that Dasein is so different from mere material being that it deserves a category of its own. But a reductive account of mind is also a reductive account of being. |
| 15584 | I say the manifestation of Being needs humans, and humans only exist as reflected in Being [Heidegger] |
| Full Idea: The fundamental thought of my thinking is precisely that Being, or the manifestation of Being, needs human beings and that, vice versa, human beings are only human beings if they are standing in the manifestation of Being. | |
| From: Martin Heidegger (Martin Heidegger in conversation [1969], p.82), quoted by Richard Polt - Heidegger: an introduction 5 'Signs' | |
| A reaction: I don't think I understand the second half of this, but I sense some sort of intuition that the consciousness of humans 'enlarges' Being, or bestows an identity on it, or some such thing. |
| 7680 | Ontology is possible only as phenomenology [Heidegger] |
| Full Idea: Ontology is possible only as phenomenology. | |
| From: Martin Heidegger (Being and Time [1927], p.31), quoted by Dale Jacquette - Ontology Ch.1 | |
| A reaction: Jacquette argues against this claim. The idea seems to be the ultimate extension of Kant, and it is not a big move to say that the only real phenomenology we can discuss is our semantics. Wrong, wrong, wrong. |
| 22161 | Readiness-to-hand defines things in themselves ontologically [Heidegger] |
| Full Idea: Readiness-to-hand is the way in which entities as they are 'in themselves' are defined ontologico-categorially. | |
| From: Martin Heidegger (Being and Time [1927], I.3.15) | |
| A reaction: I assume this is a direct reference to the problem idealists had with the thing-in-itself. It seems that the reality of a thing consists of the strengthened relationship it has with Dasein, which sounds fairly idealist to me. |
| 15576 | Heidegger seeks a non-traditional concept of essence as 'essential unfolding' [Heidegger, by Polt] |
| Full Idea: Heidegger tries to develop a non-traditional concept of essence as 'essential unfolding' ('wesen' as a verb). | |
| From: report of Martin Heidegger (Being and Time [1927], I.4.27) by Richard Polt - Heidegger: an introduction 3.§25-7 |
| 15578 | Propositions don't provide understanding, because the understanding must come first [Heidegger, by Polt] |
| Full Idea: Propositions are not a good clue to the essence of understanding, because we must already understand things before we formulate propositions about them. | |
| From: report of Martin Heidegger (Being and Time [1927], I.5.31) by Richard Polt - Heidegger: an introduction 3.§31-3 | |
| A reaction: I like this, because I think the most important aspects of our thought and understanding are entirely non-verbal - even in cases where they seem to be highly specific and verbal. We don't understand ourselves at all! |
| 22159 | If we posit 'I' as the starting point, we miss the mind's phenomenal content [Heidegger] |
| Full Idea: One of our first tasks will be to prove that if we posit an 'I' or subject as that which is proximally given, we shall completely miss the phenomenal content of Dasein. | |
| From: Martin Heidegger (Being and Time [1927], I.1.10) | |
| A reaction: Descartes had thrown doubt on the informativeness of the phenomena, so presumably your phenomenologist is not interested in whether they reveal any truth. So why are unreliable phenomena of any interest? |
| 22160 | Our relationship to a hammer strengthens when we use [Heidegger] |
| Full Idea: The less we stare at the hammer-Thing, and the more we seize hold of it and use it, the more primordial does our relationship to it become. ...The kind of Being which equipment possesses... we call 'readiness-to-hand' [Zuhandenheit]. | |
| From: Martin Heidegger (Being and Time [1927], I.3.15) | |
| A reaction: This example would be well at home in the writings of the pragmatists. It is also an important example for existentialists. In analytic philosophy we might say the experience combines perception with direct exerience of causation. |
| 15580 | There are no raw sense-data - our experiences are of the sound or colour of something [Heidegger] |
| Full Idea: We always take a noise as the sound of something; we always take a hue as the color of something. We simply do not experience raw, uninterpreted sense-data - these are the inventions of philosophers. | |
| From: Martin Heidegger (Being and Time [1927], 207/163-4), quoted by Richard Polt - Heidegger: an introduction 3.§31-3 | |
| A reaction: This is something like the modern view of sense-data as promoted by John McDowell, rather than the experiential atoms of Russell and Moore. Experience is holistic, but that doesn't mean we can't analyse it into components. |
| 20749 | Perceived objects always appear in a context [Heidegger] |
| Full Idea: The perceptual 'something' is always in the middle of something else, it always forms part of a 'field'. | |
| From: Martin Heidegger (Being and Time [1927], p.4), quoted by Kevin Aho - Existentialism: an introduction 3 'Perceptual' | |
| A reaction: Sounds like our knowledge of electrons. Nice point. Standard analytic discussions of perceiving a glass always treat it in isolation, when it is on an expensive table near a brandy bottle. Or near a hammer. |
| 22163 | The scandal of philosophy is expecting to prove reality when the prover's Being is vague [Heidegger] |
| Full Idea: The 'scandal of philosophy' is not that this proof [of external things] has yet to be given, but that such proofs are expected and attempted again and again. ...The kind of Being of the entity which does the proving has not been made definite enough. | |
| From: Martin Heidegger (Being and Time [1927], I.6.43a) | |
| A reaction: The 'scandal' was a remark of Kant's. Presumably Heidegger's exploration of Dasein aims to establish the Being of the prover sufficiently to solve this problem (via phenomenology). |
| 21949 | Having thoughts and feelings need engagement in the world [Heidegger, by Wrathall] |
| Full Idea: Heidegger argues that having thoughts and feelings is only possible for entity that is actually engaged in the world. | |
| From: report of Martin Heidegger (Being and Time [1927]) by Mark Wrathall - Heidegger: how to read 1 | |
| A reaction: This seems to be an a priori exclusion of the possibility of a brain in a vat. I guess the ancestor of this idea is Schopenhauer. |
| 22222 | Dasein finds itself already amongst others [Heidegger, by Caputo] |
| Full Idea: The world is a world shared with others, so that far from being a solipsistic ego ...Dasein finds itself already amongst others. | |
| From: report of Martin Heidegger (Being and Time [1927]) by John D. Caputo - Heidegger p.226 | |
| A reaction: Phenomenologists don't seem bothered about the problem of knowing other minds. If you take something for granted, it ceases to be a problem to be solved! |
| 8136 | If we work and play with other people, they are bound to be 'Dasein', intelligent agents [Heidegger, by Cooper,DE] |
| Full Idea: How do I know that other people have minds? The question is a bad one. Precisely because I encounter them at work, play and the like, it is guaranteed that they, too, are Dasein, intelligent agents. | |
| From: report of Martin Heidegger (Being and Time [1927], p.153-) by David E. Cooper - Heidegger Ch.3 | |
| A reaction: I've seen film of someone playing peek-a-boo with a bonobo ape, so presumably they have Dasein. It might be easier for the AI community to aim at building a robot with Dasein, than one which was simply conscious. |
| 22164 | When Dasein grasps something it exists externally alongside the thing [Heidegger] |
| Full Idea: When Dasein directs itself towards something and grasps it, it does not somehow first get out of an inner sphere in which it has been proximally encapsulated, but its primary kind of Being is such that it is always 'outside' alongside entities. | |
| From: Martin Heidegger (Being and Time [1927], I.2.13) | |
| A reaction: This is the first plausible fruit of phenomenology I have been able to discover. Analysing the passive mind is not very promising, but seeing what happens when we become more proactive is revealing. |
| 15579 | My active existence is defined by being able to say 'I can' [Heidegger] |
| Full Idea: The Dasein which I myself am in each instance is defined in its Being by my being able to say of it, 'I am, that is, I can'. | |
| From: Martin Heidegger (History of the Concept of Time [1925], p.298), quoted by Richard Polt - Heidegger: an introduction 3.§31-3 | |
| A reaction: I like this emphasis on the more active aspect of the Cogito idea. The whole Enlightenment account of things has them as inert, and falling under laws and theories. The Aristotelian account makes potentiality central. |
| 15583 | Certainty that I will die is more basic to my existence than the Cogito [Heidegger] |
| Full Idea: The certainty that 'I myself am in that I will die' is the basic certainty of Dasein itself. It is a genuine statement of Dasein, while 'cogito sum' is only a semblance of such a statement. | |
| From: Martin Heidegger (History of the Concept of Time [1925], p.316-7), quoted by Richard Polt - Heidegger: an introduction 4.§46-53 | |
| A reaction: This just seems to be false. Children face their existence in thought long before they face their mortality. Absorption in activity can marginalise death, but not marginalise thought. |
| 22162 | There is an everyday self, and an authentic self, when it is grasped in its own way [Heidegger] |
| Full Idea: The self of everyday Dasein is the they-self [das Man-selbst], which we distinguish from the authentic self - that is, from the Self which has been taken hold of in its own way. | |
| From: Martin Heidegger (Being and Time [1927], I.4.27) | |
| A reaction: To a novice this sounds like a requirement for increased self-consciousness during daily activity. 'Be a good animal, true to your animal self' said one of Lawrence's characters. |
| 20114 | Everyone is other, and no one is himself [Heidegger] |
| Full Idea: Everyone is other, and no one is himself. | |
| From: Martin Heidegger (Being and Time [1927], p.165), quoted by Rüdiger Safranski - Nietzsche: a philosophical biography 09 | |
| A reaction: Safranski describes this as the idea of 'structural self-evasion'. He detects the same idea in Nietzsche's 'Daybreak'. |
| 15577 | Moods are more fundamentally revealing than theories - as when fear reveals a threat [Heidegger, by Polt] |
| Full Idea: For Heidegger moods are disclosive; they show us things in a more fundamental way than theoretical propositions ever can. For example, fear reveals something as a threat. | |
| From: report of Martin Heidegger (Being and Time [1927], I.5.30) by Richard Polt - Heidegger: an introduction 3.§30 | |
| A reaction: Most modern students of emotion seem to agree. Even though they may not have specific content, it is always possible to consider the underlying cause of the mood. |
| 20748 | We do not add value to naked things; its involvement is disclosed in understanding it [Heidegger] |
| Full Idea: We do not throw a 'signification' over some naked thing which is present-at-hand, we do not stick a value on it; but when something is encountered as such, the thing in question has an involvement which is disclosed in our understanding of the world. | |
| From: Martin Heidegger (Being and Time [1927], p.190-1), quoted by George Dickie - The Myth of the Aesthetic Attitude 3 'Undoing' | |
| A reaction: Analytic philosophy and science have tried to dismantle experience, and Heidegger wants to put it back together. I would say there is a big difference between encountering a thing (which is a bit facty), and understanding it (which is more valuey). |
| 22166 | Dasein has the potential to be itself, but must be shown this in the midst of ordinariness [Heidegger] |
| Full Idea: Because Dasein is lost in the 'they', it must first find itself. It must be 'shown' to itself in its possible authenticity. In terms of its possibility, Dasein is already a potentiality-for-Being-its-self, but it needs to have this potentiality attested. | |
| From: Martin Heidegger (Being and Time [1927], II.2.54) | |
| A reaction: I wish there was some criterion for knowing when you are being yourself and when you are not. |
| 22165 | Anxiety reveals the possibility and individuality of Dasein [Heidegger] |
| Full Idea: Anxiety discloses Dasein as Being-possible, and indeed as the only kind of thing which it can be of its own accord as something individualised in individualisation. | |
| From: Martin Heidegger (Being and Time [1927], I.6.40) | |
| A reaction: Is sounds like insecurity, as a sort of trauma that shocks one into self-realisation. The idea means very little to me personally. |
| 21952 | Anxiety about death frees me to live my own life [Heidegger, by Wrathall] |
| Full Idea: For Heidegger, as a consequence of my anxiety in the face of death, I am set free to live my life as my own rather than doing things merely because others expect me to do them. | |
| From: report of Martin Heidegger (Being and Time [1927]) by Mark Wrathall - Heidegger: how to read 7 | |
| A reaction: Contrary to Epicurus, Heidegger thinks anxiety about death is a good thing. The point is, I suppose, that we all die alone, and people who are very socially contrained need to face up to death in order to grasp their autonomy. |
| 22224 | Anxiety is the uncanniness felt when constantly fleeing from asserting one's own freedom [Heidegger, by Caputo] |
| Full Idea: Anxiety [angst] is the disturbing sense of uncanniness by which Dasein is overtaken (thrownness) when it discovers there is nothing other than its own freedom to sustain its projects (projection), and from which Dasein constantly takes flight (falling). | |
| From: report of Martin Heidegger (Being and Time [1927]) by John D. Caputo - Heidegger p.227 | |
| A reaction: This seems to be Kierkegaard's idea, unamended. In my experience anxiety only comes when I am forced into making decisions by worldly situations. An 'existential crisis' is a sort of blankness appearing where a future life was supposed to be. |
| 20767 | Culture is now dominated by boredom, so universal it is unnoticed [Heidegger, by Aho] |
| Full Idea: Heidegger came to say that the cultural mood had changed from 'anxiety' to 'boredom'. The danger is that our boredom has become so ubiquitous and all-encompassing that it is now hidden. | |
| From: report of Martin Heidegger (Contributions to Philosophy [1938]) by Kevin Aho - Existentialism: an introduction 9 'Conc' | |
| A reaction: I'm not sure what the danger of boredom is if it is 'hidden'. It rather depends what else is hidden with it. |
| 15572 | Being what it is (essentia) must be conceived in terms of Being (existence) [Heidegger] |
| Full Idea: Dasein's Being-what-it-is (essentia) must….be conceived in terms of its Being (existentia). | |
| From: Martin Heidegger (Being and Time [1927], 67/42), quoted by Richard Polt - Heidegger: an introduction 3.§2 | |
| A reaction: This seems to be the origin of Sartre's famous slogan 'existence before essence'. It seems to be a rebellion against Husserl's quest for essences. |
| 20453 | Heidegger says we must either choose an inauthentic hero, or choose yourself as hero [Heidegger, by Critchley] |
| Full Idea: Heidegger says you must choose your hero; either you choose 'das Man', the inauthentic life, or you choose yourself - the point being that you have to choose yourself as your hero in order to be authentic. | |
| From: report of Martin Heidegger (Being and Time [1927]) by Simon Critchley - Impossible Objects: interviews 5 | |
| A reaction: If Nietzsche's 'Ecce Homo' is the model for choosing yourself as hero, I am not too sure about this idea. Needing a hero seems awfully German and romantic. Ein Heldenleben. Be your own anit-hero (like a standup comedian)? |
| 15581 | Dasein is always only that which it has chosen to be [Heidegger] |
| Full Idea: Dasein is always only that which it has chosen to be. | |
| From: Martin Heidegger (Basic Problems of Phenomenology [1927], p.278), quoted by Richard Polt - Heidegger: an introduction 3.§39-42 | |
| A reaction: I take it as significant that this is what it 'has' chosen, and not what it now 'chooses'. I might accept that my mode of existence results from past choices, but certainly not that I can choose it now. Ossified brain. |
| 6005 | Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley] |
| Full Idea: Hermarchus said that animal killing is justified by considerations of human safety and nourishment and by animals' inability to form contractual relations of justice with us. | |
| From: report of Hermarchus (fragments/reports [c.270 BCE]) by David A. Sedley - Hermarchus | |
| A reaction: Could the last argument be used to justify torturing animals? Or could we eat a human who was too brain-damaged to form contracts? |