27 ideas
| 19115 | You can 'rebut' an argument's conclusion, or 'undercut' its premises [Antonelli] |
| Full Idea: A 'rebut' of an argument establishes that its conclusion is not the case. An 'undercut' of the argument shows that the premises do not support that conclusion. | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 3.2) |
| 19119 | We infer that other objects are like some exceptional object, if they share some of its properties [Antonelli] |
| Full Idea: The exceptional status of an object with respect to some default is more likely to spread to other objects if they share properties with that object that may play a role in explaining the exceptional status. | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 4) | |
| A reaction: This is an example of the sort of rational behaviour we exhibit, and which a 'real life' logic would somehow need to capture. I would suggest the essentialist logic designed by Kit Fine as a first port of call. |
| 19111 | Reasoning may be defeated by new premises, or by finding out more about the given ones [Antonelli] |
| Full Idea: Most defeasible reasoning is externally dynamic, affected by the addition of further premises. But there is also an internal (or 'diachronic') dynamic, when further analysis reveals more about the given premises. | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 1) |
| 19114 | Should we accept Floating Conclusions, derived from two arguments in conflict? [Antonelli] |
| Full Idea: There is much discussion of whether Floating Conclusions should be derived, given that they were derived from two arguments which conflict with one another. | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 2.3) |
| 19113 | Weakest Link Principle: prefer the argument whose weakest link is the stronger [Antonelli] |
| Full Idea: In the Weakest Link Principle, an argument is preferred to another conflicting argument if its weakest defeasible link is stronger than the weakest defeasible link in the conflicting argument. | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 2.1) | |
| A reaction: [He cites John Pollock 1991] This sounds like the elementary principle applied when choosing a rope by which to hang a large weight above your head. It gets non-monotonic logic off the ground - if you know how to evaluate 'weakest'. |
| 19116 | Non-monotonic core: Reflexivity, Cut, Cautious Monotonicity, Left Logical Equivalence, Right Weakening [Antonelli] |
| Full Idea: Conservative core of non-monotonic logic:Reflexivity (p proves p), Cut (if p proves q, it proves their joint implications), Cautious Monotonicity, Left Logical Equivalence (equivalences have same consequences), Right Weakening (non-m preserves classical). | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 3.5.1) | |
| A reaction: [Highly compressed, and without symbols] |
| 19117 | We can rank a formula by the level of surprise if it were to hold [Antonelli] |
| Full Idea: We can think of an 'ordinal ranking function' κ([φ)] as the level of surprise we would face were φ to hold, up to maximal surprise. | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 3.5.2) | |
| A reaction: This suggests that Bayes's Theorem might be relevant to non-monotonic logic. This suggests that registering surprise would need to be an important feature of robot behaviour. |
| 19118 | People don't actually use classical logic, but may actually use non-monotonic logic [Antonelli] |
| Full Idea: Test subjects seem to perform very poorly in various reasoning tests (Wason Selection, Suppression Task), suggesting logic has a subordinate role, but this may be using classical logic, where non-monotonic logics would be more appropriate. | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 4) | |
| A reaction: Fred Sommers presents his Term Logic (based on Aristotle) as closer to how people actually reason. It is certainly crazy to infer that most people's everyday reasoning is irrational. Induction is highly rational; it's just not deductive. |
| 19110 | In classical logic the relation |= has Monotony built into its definition [Antonelli] |
| Full Idea: In classical logic, Monotony follows immediately from the nature of the relation |=, for Γ |= φ holds precisely when φ is true on every interpretation on which all sentences in Γ are true. | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 1) | |
| A reaction: That is, semantic consequence (|=) is defined in terms of a sentence (φ) always being true if some other bunch of sentences (Γ) are true. Hence the addition of further sentences to Γ will make no difference - which is Monotony. |
| 19112 | Cautious Monotony ignores proved additions; Rational Monotony fails if the addition's negation is proved [Antonelli] |
| Full Idea: Basic Monotony: something stays proved if further premises are added. Cautious Monotony: the addition of something which has been proved makes no difference. Rational Monotony: it stays proved as long as the addition's negation hasn't been proved. | |
| From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 1) | |
| A reaction: [A compressed and non-symbolic summary] |
| 3847 | Man is nothing else but the sum of his actions [Sartre] |
| Full Idea: Man is nothing else but the sum of his actions. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.41) | |
| A reaction: This might be plausible if unperformed actions are included. For some people, their whole life story consists of what they failed to do. |
| 3846 | Man IS freedom [Sartre] |
| Full Idea: There is no determinism - man is free, man IS freedom. …Man is condemned to be free. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.34) |
| 3843 | There is no human nature [Sartre] |
| Full Idea: There is no human nature. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.28) | |
| A reaction: Everything which can be individuated has a nature, say I, wearing my Aristotelian lapel badge. Does he think the same of cats? Does he think the mind is a blank page? |
| 6017 | Nomos is king [Pindar] |
| Full Idea: Nomos is king. | |
| From: Pindar (poems [c.478 BCE], S 169), quoted by Thomas Nagel - The Philosophical Culture | |
| A reaction: This seems to be the earliest recorded shot in the nomos-physis wars (the debate among sophists about moral relativism). It sounds as if it carries the full relativist burden - that all that matters is what has been locally decreed. |
| 20762 | There are no values to justify us, and no excuses [Sartre] |
| Full Idea: There are no values or commands to turn to which legitimize our conduct. …We are alone with no excuses. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.296), quoted by Kevin Aho - Existentialism: an introduction 6 'Bad' | |
| A reaction: If there are no values or duties, why might you ever need excuses? |
| 3852 | If values depend on us, freedom is the foundation of all values [Sartre] |
| Full Idea: Once a man has seen that values depend upon himself, he can only will one thing, and that is freedom as the foundation of all values. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.51) | |
| A reaction: I don't think so. Is freedom the foundation of all arithmetic, because I am untrammelled when doing addition? Values are ridiculous if they don't reflect facts. |
| 20764 | In becoming what we want to be we create what we think man ought to be [Sartre] |
| Full Idea: In creating the man that we want to be, there is not a single one of our acts which does not at the same time create an image of man as we think he ought to be. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.293), quoted by Kevin Aho - Existentialism: an introduction 7 'Anything' | |
| A reaction: I recall this being one of my earliest thoughts about morality - that in everything we do we are all role models for the people around us. For me, that leads to virtue theory. |
| 3848 | Cowards are responsible for their cowardice [Sartre] |
| Full Idea: The existentialist, when he portrays a coward, shows him as responsible for his cowardice. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.42) |
| 20763 | When my personal freedom becomes involved, I must want freedom for everyone else [Sartre] |
| Full Idea: Freedom as the definition of man does not depend on others, but as soon as there is involvement, I am obliged to want others to have freedom at the same time that I want my own freedom. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.306), quoted by Kevin Aho - Existentialism: an introduction 7 'Anything' | |
| A reaction: Appears to be a highly Kantian sense of rational duty, and a rather odd constraint on someone whose only value is freedom. Sartre is aware that he needs an existential politics, but he's not there yet. 'Involvement' is an interesting addition to Kant. |
| 22229 | Existentialists says that cowards and heroes make themselves [Sartre] |
| Full Idea: What the existentialist says is that the coward makes himself cowardly, that the hero makes himself heroic. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.35), quoted by Christine Daigle - Jean-Paul Sartre 2.3 | |
| A reaction: A nice statement of the existential plasticity of the self, in opposition to the much stronger concept of human nature in Aristotle (who nevertheless believes you can acquire virtues and vices). |
| 3842 | Existence before essence (or begin with the subjective) [Sartre] |
| Full Idea: Existentialism says that existence comes before essence - or, if you will, that we must begin from the subjective. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.26) |
| 6868 | 'Existence precedes essence' means we have no pre-existing self, but create it through existence [Sartre, by Le Poidevin] |
| Full Idea: I take 'existence precedes essence' to mean that we do not have a pre-existing self, which organises our behaviour, but rather that we create our self as we go along, through our existence and activities. | |
| From: report of Jean-Paul Sartre (Existentialism and Humanism [1945]) by Robin Le Poidevin - Interview with Baggini and Stangroom p.222 | |
| A reaction: The direct opponent of this is Aristotle, who builds his ethics on a fairly fixed human nature, but even he agrees that we mould our moral characters through our activities, in a circular way. There are not, though, infinite possibilities in mankind. |
| 3844 | Existentialism says man is whatever he makes of himself [Sartre] |
| Full Idea: Man is nothing else but that which he makes of himself. This is the first principle of existentialism. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.28) |
| 20754 | It is dishonest to offer passions as an excuse [Sartre] |
| Full Idea: Every man who takes refuge behind the excuse of his passions is a dishonest man. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.305), quoted by Kevin Aho - Existentialism: an introduction 5 'Core' | |
| A reaction: To say 'my passion was so strong that I was too weak to resist it' doesn't sound prima facie dishonest. Sartre's idea is more of an exhortation than a fact, and sounds rather old fashioned and puritan. Do my reasons constitutes excuses? |
| 6571 | When a man must choose between his mother and the Resistance, no theory can help [Sartre, by Fogelin] |
| Full Idea: When a young man must choose between his bereft mother and the French Resistance, Sartre says no moral theory is capable of resolving the dilemma; the man must act on his own, and in the process define his moral character. | |
| From: report of Jean-Paul Sartre (Existentialism and Humanism [1945], p.35-9) by Robert Fogelin - Walking the Tightrope of Reason Ch.2 | |
| A reaction: Fogelin agrees, but rejects Sartre's claim that all morality is like this. I agree with Fogelin. However, what I like is the idea of 'defining one's moral character' by choices, but that is because it endorses the views of Aristotle (e.g. Idea 4394). |
| 3851 | If I do not choose, that is still a choice [Sartre] |
| Full Idea: If I do not choose, that is still a choice. | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.48) |
| 3845 | Without God there is no intelligibility or value [Sartre] |
| Full Idea: For the atheist existentialist there disappears with God all possibility of finding values in an intelligible heaven. (Dostoevsky wrote "If God did not exist, everything would be permitted"). | |
| From: Jean-Paul Sartre (Existentialism and Humanism [1945], p.33) |