17 ideas
7914 | To try to be wise all on one's own is folly [Rochefoucauld] |
Full Idea: To try to be wise all on one's own is sheer folly. | |
From: La Rochefoucauld (Maxims [1663], 231) | |
A reaction: I agree strongly with this. There are counter-examples, of whom Spinoza may be the greatest, and Nietzsche thought that philosophy was essentially a solitary business, but most of us are not Spinoza or Nietzsche. |
13913 | The four 'perfect syllogisms' are called Barbara, Celarent, Darii and Ferio [Engelbretsen/Sayward] |
Full Idea: There are four 'perfect syllogisms': Barbara (every M is P, every S is M, so every S is P); Celarent (no M is P, every S is M, so no S is P); Darii (every M is P, some S is M, so some S is P); Ferio (no M is P, some S is M, so some S is not P). | |
From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8) | |
A reaction: The four names are mnemonics from medieval universities. |
13914 | Syllogistic logic has one rule: what is affirmed/denied of wholes is affirmed/denied of their parts [Engelbretsen/Sayward] |
Full Idea: It has often been claimed (e.g. by Leibniz) that a single rule governs all syllogistic validity, called 'dictum de omni et null', which says that what is affirmed or denied of any whole is affirmed or denied of any part of that whole. | |
From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8) | |
A reaction: This seems to be the rule which is captured by Venn Diagrams. |
13915 | Syllogistic can't handle sentences with singular terms, or relational terms, or compound sentences [Engelbretsen/Sayward] |
Full Idea: Three common kinds of sentence cannot be put into syllogistic ('categorical') form: ones using singular terms ('Mars is red'), ones using relational terms ('every painter owns some brushes'), and compound sentences. | |
From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8) |
13916 | Term logic uses expression letters and brackets, and '-' for negative terms, and '+' for compound terms [Engelbretsen/Sayward] |
Full Idea: Term logic begins with expressions and two 'term functors'. Any simple letter is a 'term', any term prefixed by a minus ('-') is a 'negative term', and any pair of terms flanking a plus ('+') is a 'compound term'. Parenthese are used for grouping. | |
From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 8) | |
A reaction: [see Engelbretsen and Sayward for the full formal system] |
13850 | In modern logic all formal validity can be characterised syntactically [Engelbretsen/Sayward] |
Full Idea: One of the key ideas of modern formal logic is that all formally valid inferences can be specified in strictly syntactic terms. | |
From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], Ch.2) |
13849 | Classical logic rests on truth and models, where constructivist logic rests on defence and refutation [Engelbretsen/Sayward] |
Full Idea: Classical logic rests on the concepts of truth and falsity (and usually makes use of a semantic theory based on models), whereas constructivist logic accounts for inference in terms of defense and refutation. | |
From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], Intro) | |
A reaction: My instincts go with the classical view, which is that inferences do not depend on the human capacity to defend them, but sit there awaiting revelation. My view isn't platonist, because I take the inferences to be rooted in the physical world. |
13851 | Unlike most other signs, = cannot be eliminated [Engelbretsen/Sayward] |
Full Idea: Unlike ∨, →, ↔, and ∀, the sign = is not eliminable from a logic. | |
From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], Ch.3) |
13852 | Axioms are ω-incomplete if the instances are all derivable, but the universal quantification isn't [Engelbretsen/Sayward] |
Full Idea: A set of axioms is said to be ω-incomplete if, for some universal quantification, each of its instances is derivable from those axioms but the quantification is not thus derivable. | |
From: Engelbretsen,G/Sayward,C (Philosophical Logic: Intro to Advanced Topics [2011], 7) |
7118 | La Rochefoucauld's idea of disguised self-love implies an unconscious mind [Rochefoucauld, by Sartre] |
Full Idea: La Rochefoucauld is one of the first to have made use of the unconscious without naming it: for him, amour-propre conceals itself in the most diverse disguises. | |
From: report of La Rochefoucauld (Maxims [1663]) by Jean-Paul Sartre - Transcendence of the Ego I (C) | |
A reaction: It seems odd that no one before that ever thought that someone might have hidden motives of which even they themselves were unaware. How about Iago, or Macbeth, or Hamlet? It is a profound change in our view of human nature. |
7912 | Judging by effects, love looks more like hatred than friendship [Rochefoucauld] |
Full Idea: If love be judged by its most visible effects it looks more like hatred than friendship. | |
From: La Rochefoucauld (Maxims [1663], 072) | |
A reaction: Presumably he is thinking of pursuit, possession and jealousy. The remark is plausible if you add the word 'sometimes' to it, but as a universal generalisation it is ridiculous, the product of a society where they competed to exceed in cynicism. |
7915 | Supreme cleverness is knowledge of the real value of things [Rochefoucauld] |
Full Idea: Supreme cleverness is knowledge of the real value of things. | |
From: La Rochefoucauld (Maxims [1663], 244) | |
A reaction: Good. Right at the heart of wisdom is some kind of grasp of right values. It is so complex and subtle that it seems like pure intuition, but I am sure that reason is involved. 'Intelligent' people tend to be better at it. Some justifications can be given. |
7917 | Realising our future misery is a kind of happiness [Rochefoucauld] |
Full Idea: To realise how much misery we have to face is in itself a kind of happiness. | |
From: La Rochefoucauld (Maxims [1663], 570) | |
A reaction: Probably true. Knowing that you have got hold of the truth is a sort of happiness in any area, no matter how grim the truth. However, a happy life could easily be poisoned by brooding on the future. Should the happily married brood on future solitude? |
7913 | Virtue doesn't go far without the support of vanity [Rochefoucauld] |
Full Idea: Virtue would not go far without vanity to bear it company. | |
From: La Rochefoucauld (Maxims [1663], 200) | |
A reaction: Rochefoucauld's cynicism gets a bit tedious, but lovers of virtue must face up to this possibility when they consider what motivates them. At the heart of Aristotle there is a missing question, of what is so good about right-functioning and virtue. |
7916 | True friendship is even rarer than true love [Rochefoucauld] |
Full Idea: Rare though true love may be, true friendship is rarer still. | |
From: La Rochefoucauld (Maxims [1663], 473) | |
A reaction: This seems to be true. Our culture doesn't encourage friendship as a high ideal. Are women better at friendship than men? Which culture, past or present, led to the greatest flourishing of friendship? Epicurus's Garden? |
9299 | We are bored by people to whom we ourselves are boring [Rochefoucauld] |
Full Idea: Almost always we are bored by people to whom we ourselves are boring. | |
From: La Rochefoucauld (Maxims [1663], 555) | |
A reaction: An obvious exception would be a celebrity being bored with their fans. Their very excess of interest is precisely what is boring. If two people communicate well, it is unlikely that either of them will ever be bored. |
1513 | The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus] |
Full Idea: The Egyptians were the first to claim that the soul of a human being is immortal, and that each time the body dies the soul enters another creature just as it is being born. | |
From: Herodotus (The Histories [c.435 BCE], 2.123.2) |