100 ideas
| 19608 | Wisdom is just the last gasp of a dying civilization [Cioran] |
| 19631 | The history of ideas (and deeds) occurs in a meaningless environment [Cioran] |
| 19624 | Intelligence only fully flourishes at the end of a historical period [Cioran] |
| 19599 | Ideas are neutral, but people fill them with passion and weakness [Cioran] |
| 19629 | A nation gives expression to its sum of values, and is then exhausted [Cioran] |
| 19645 | Some thinkers would have been just as dynamic, no matter when they had lived [Cioran] |
| 19618 | I abandoned philosophy because it didn't acknowledge melancholy and human weakness [Cioran] |
| 19621 | Originality in philosophy is just the invention of terms [Cioran] |
| 19607 | The mind is superficial, only concerned with the arrangement of events, not their significance [Cioran] |
| 19638 | Metaphysics is a universalisation of physical anguish [Cioran] |
| 19620 | Great systems of philosophy are just brilliant tautologies [Cioran] |
| 19630 | No great idea ever emerged from a dialogue [Cioran] |
| 19636 | Truth is just an error insufficiently experienced [Cioran] |
| 19642 | Eventually every 'truth' is guaranteed by the police [Cioran] |
| 9535 | 'Contradictory' propositions always differ in truth-value [Lemmon] |
| 9509 | That proposition that both P and Q is their 'conjunction', written P∧Q [Lemmon] |
| 9508 | The sign |- may be read as 'therefore' [Lemmon] |
| 9514 | If A and B are 'interderivable' from one another we may write A -||- B [Lemmon] |
| 9511 | We write the conditional 'if P (antecedent) then Q (consequent)' as P→Q [Lemmon] |
| 9512 | We write the 'negation' of P (not-P) as ¬ [Lemmon] |
| 9510 | That proposition that either P or Q is their 'disjunction', written P∨Q [Lemmon] |
| 9513 | We write 'P if and only if Q' as P↔Q; it is also P iff Q, or (P→Q)∧(Q→P) [Lemmon] |
| 9516 | A 'well-formed formula' follows the rules for variables, ¬, →, ∧, ∨, and ↔ [Lemmon] |
| 9532 | 'Subcontrary' propositions are never both false, so that A∨B is a tautology [Lemmon] |
| 9531 | 'Contrary' propositions are never both true, so that ¬(A∧B) is a tautology [Lemmon] |
| 9528 | A wff is a 'tautology' if all assignments to variables result in the value T [Lemmon] |
| 9530 | A wff is 'contingent' if produces at least one T and at least one F [Lemmon] |
| 9519 | A 'substitution-instance' is a wff formed by consistent replacing variables with wffs [Lemmon] |
| 9529 | A wff is 'inconsistent' if all assignments to variables result in the value F [Lemmon] |
| 9534 | Two propositions are 'equivalent' if they mirror one another's truth-value [Lemmon] |
| 9517 | The 'scope' of a connective is the connective, the linked formulae, and the brackets [Lemmon] |
| 9518 | A 'theorem' is the conclusion of a provable sequent with zero assumptions [Lemmon] |
| 9533 | A 'implies' B if B is true whenever A is true (so that A→B is tautologous) [Lemmon] |
| 9393 | A: we may assume any proposition at any stage [Lemmon] |
| 9400 | ∨I: Given either A or B separately, we may derive A∨B [Lemmon] |
| 9396 | DN: Given A, we may derive ¬¬A [Lemmon] |
| 9398 | ∧I: Given A and B, we may derive A∧B [Lemmon] |
| 9394 | MPP: Given A and A→B, we may derive B [Lemmon] |
| 9399 | ∧E: Given A∧B, we may derive either A or B separately [Lemmon] |
| 9401 | ∨E: Derive C from A∨B, if C can be derived both from A and from B [Lemmon] |
| 9395 | MTT: Given ¬B and A→B, we derive ¬A [Lemmon] |
| 9402 | RAA: If assuming A will prove B∧¬B, then derive ¬A [Lemmon] |
| 9397 | CP: Given a proof of B from A as assumption, we may derive A→B [Lemmon] |
| 9522 | 'Modus ponendo tollens' (MPT) says P, ¬(P ∧ Q) |- ¬Q [Lemmon] |
| 9526 | We can change conjunctions into negated conditionals with P→Q -||- ¬(P → ¬Q) [Lemmon] |
| 9527 | The Distributive Laws can rearrange a pair of conjunctions or disjunctions [Lemmon] |
| 9523 | De Morgan's Laws make negated conjunctions/disjunctions into non-negated disjunctions/conjunctions [Lemmon] |
| 9524 | We can change conditionals into disjunctions with P→Q -||- ¬P ∨ Q [Lemmon] |
| 9525 | We can change conditionals into negated conjunctions with P→Q -||- ¬(P ∧ ¬Q) [Lemmon] |
| 9521 | 'Modus tollendo ponens' (MTP) says ¬P, P ∨ Q |- Q [Lemmon] |
| 9537 | Truth-tables are good for showing invalidity [Lemmon] |
| 9538 | A truth-table test is entirely mechanical, but this won't work for more complex logic [Lemmon] |
| 9536 | If any of the nine rules of propositional logic are applied to tautologies, the result is a tautology [Lemmon] |
| 9539 | Propositional logic is complete, since all of its tautologous sequents are derivable [Lemmon] |
| 13909 | Write '(∀x)(...)' to mean 'take any x: then...', and '(∃x)(...)' to mean 'there is an x such that....' [Lemmon] |
| 13902 | 'Gm' says m has property G, and 'Pmn' says m has relation P to n [Lemmon] |
| 13911 | The 'symbols' are bracket, connective, term, variable, predicate letter, reverse-E [Lemmon] |
| 13910 | Our notation uses 'predicate-letters' (for 'properties'), 'variables', 'proper names', 'connectives' and 'quantifiers' [Lemmon] |
| 13904 | Universal Elimination (UE) lets us infer that an object has F, from all things having F [Lemmon] |
| 13901 | Predicate logic uses propositional connectives and variables, plus new introduction and elimination rules [Lemmon] |
| 13903 | Universal elimination if you start with the universal, introduction if you want to end with it [Lemmon] |
| 13906 | With finite named objects, we can generalise with &-Intro, but otherwise we need ∀-Intro [Lemmon] |
| 13908 | UE all-to-one; UI one-to-all; EI arbitrary-to-one; EE proof-to-one [Lemmon] |
| 13905 | If there is a finite domain and all objects have names, complex conjunctions can replace universal quantifiers [Lemmon] |
| 13900 | 'Some Frenchmen are generous' is rendered by (∃x)(Fx→Gx), and not with the conditional → [Lemmon] |
| 9520 | The paradoxes of material implication are P |- Q → P, and ¬P |- P → Q [Lemmon] |
| 19632 | An axiom has no more authority than a frenzy [Cioran] |
| 19626 | Our instincts had to be blunted and diminished, to make way for consciousness! [Cioran] |
| 19633 | We use concepts to master our fears; saying 'death' releases us from confronting it [Cioran] |
| 19615 | I want to suppress in myself the normal reasons people have for action [Cioran] |
| 19628 | At a civilisation's peak values are all that matters, and people unconsciously live by them [Cioran] |
| 19646 | Values don't accumulate; they are ruthlessly replaced [Cioran] |
| 19614 | Lovers are hateful, apart from their hovering awareness of death [Cioran] |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
| 19619 | To live authentically, we must see that philosophy is totally useless [Cioran] |
| 19634 | Man is never himself; he always aims at less than life, or more than life [Cioran] |
| 19622 | The pointlessness of our motives and irrelevance of our gestures reveals our vacuity [Cioran] |
| 19612 | The universe is dirty and fragile, as if a scandal in nothingness had produced its matter [Cioran] |
| 19617 | Evidence suggests that humans do not have a purpose [Cioran] |
| 19604 | Unlike other creatures, mankind seems lost in nature [Cioran] |
| 19606 | We can only live because our imagination and memory are poor [Cioran] |
| 19601 | Life is now more dreaded than death [Cioran] |
| 19640 | No one is brave enough to say they don't want to do anything; we despise such a view [Cioran] |
| 19602 | You are stuck in the past if you don't know boredom [Cioran] |
| 19641 | If you lack beliefs, boredom is your martyrdom [Cioran] |
| 19644 | History is the bloody rejection of boredom [Cioran] |
| 19613 | It is pointless to refuse or accept the social order; we must endure it like the weather [Cioran] |
| 19627 | Opportunists can save a nation, and heroes can ruin it [Cioran] |
| 19625 | The ideal is to impose a religion by force, and then live in doubt about its beliefs [Cioran] |
| 19605 | Despite endless suggestions, no one has found a goal for history [Cioran] |
| 19637 | History is wonderfully devoid of meaning [Cioran] |
| 19611 | No one has ever found a good argument against suicide [Cioran] |
| 19610 | Religions see suicide as insubordination [Cioran] |
| 19609 | If you have not contemplated suicide, you are a miserable worm [Cioran] |
| 19639 | We all need sexual secrets! [Cioran] |
| 19603 | Why is God so boring, and why does God resemble humanity so little? [Cioran] |
| 19616 | As the perfect wisdom of detachment, philosophy offers no rivals to Taoism [Cioran] |
| 19600 | When man abandons religion, he then follows new fake gods and mythologies [Cioran] |
| 19643 | A religion needs to motivate killings, and cannot tolerate rivals [Cioran] |
| 19623 | Circles of hell are ridiculous; all that matters is to be there [Cioran] |