18 ideas
| 23881 | All thought about values is philosophical, and thought about anything else is not philosophy [Weil] |
| Full Idea: All reflections bearing on the notion of value and on the hierarchy of values is philosophical; all efforts of thought bearing on anything other than value are, if one examines them closely, foreign to philosophy. | |
| From: Simone Weil (Reflections on Value [1941], p.30) | |
| A reaction: If nothing else proves that Weil is a platonist, this does. She, of course, has a transcendent and religious view of values, whereas I just see them as concepts which embody what is important. That said, I'm not far off agreeing with this. |
| 23885 | Philosophy aims to change the soul, not to accumulate knowledge [Weil] |
| Full Idea: Philosophy does not consist in accumulating knowledge, as science does, but in changing the whole soul. | |
| From: Simone Weil (Reflections on Value [1941], p.33) | |
| A reaction: I agree, roughly. In the sense that philosophy is a much more personal matter than any pure pursuit of knowledge, such as geology. Though a life in geology could change your soul. Not just any old change, of course…. |
| 23886 | Systems are not unique to each philosopher. The platonist tradition is old and continuous [Weil] |
| Full Idea: People believe that every philosopher has a system that contradicts all the others! But there is a tradition, genuinely philosophical, that is as old as humanity itself. …Plato is the most perfect representative of this tradition. | |
| From: Simone Weil (Reflections on Value [1941], p.33) | |
| A reaction: I see roughly two traditions. If you believe in transcendence you follow Plato, like Simone. If you are a naturalist (like me) you follow Aristotle. A third tradition might be much more sceptical. |
| 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) |
| 23884 | Truth is a value of thought [Weil] |
| Full Idea: Truth is a value of thought. The word 'truth' cannot have any other meaning. | |
| From: Simone Weil (Reflections on Value [1941], p.32) | |
| A reaction: This makes a nice change from truth being a mere predicate. I would call truth the criterion of success in thought, and that counts as a value, so she is right. |
| 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) |
| 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'. |
| 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) |
| 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. |
| 9390 | Logic guides thinking, but it isn't a substitute for it [Rumfitt] |
| Full Idea: Logic is part of a normative theory of thinking, not a substitute for thinking. | |
| From: Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.13) | |
| A reaction: There is some sort of logicians' dream, going back to Leibniz, of a reasoning engine, which accepts propositions and outputs inferences. I agree with this idea. People who excel at logic are often, it seems to me, modest at philosophy. |
| 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] |
| 9389 | Vague membership of sets is possible if the set is defined by its concept, not its members [Rumfitt] |
| Full Idea: Vagueness in respect of membership is consistency with determinacy of the set's identity, so long as a set's identity is taken to consist, not in its having such-and-such members, but in its being the extension of a concept. | |
| From: Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.5) | |
| A reaction: I find this view of sets much more appealing than the one that identifies a set with its members. The empty set is less of a problem, as well as non-existents. Logicians prefer the extensional view because it is tidy. |
| 23882 | Ends, unlike means, cannot be defined, which is why people tend to pursue means [Weil] |
| Full Idea: Everything that can be taken as an end cannot be defined. Means, such as power and money, are easily defined, and that is why people orient themselves exclusively towards the acquisition of means. | |
| From: Simone Weil (Reflections on Value [1941], p.31) | |
| A reaction: Nice, but too neat, because so many activities can be treated either as means or as ends, and often as both. It makes sense that people pursue what is clear to them. |
| 23883 | Minds essentially and always strive towards value [Weil] |
| Full Idea: For the mind essentially and always, in whatever manner it is disposed, strives towards value. | |
| From: Simone Weil (Reflections on Value [1941], p.31) | |
| A reaction: A typically platonist thought. If you accept my view that values identify what is important, the thought is plausible. We might distinguish between what the mind pointlessly entertains, and what it 'strives' for. |