11 ideas
10245 | One geometry cannot be more true than another [Poincaré] |
Full Idea: One geometry cannot be more true than another; it can only be more convenient. | |
From: Henri Poincaré (Science and Method [1908], p.65), quoted by Stewart Shapiro - Philosophy of Mathematics | |
A reaction: This is the culminating view after new geometries were developed by tinkering with Euclid's parallels postulate. |
11184 | Aristotelian essentialism is about shared properties, individuating essentialism about distinctive properties [Marcus (Barcan)] |
Full Idea: An object must have some of its natural properties in this world. Some of those it has in common with objects of some proximate kind (Aristotelian essentialism), and others individuate it from objects of the same kind (individuating essentialism). | |
From: Ruth Barcan Marcus (Essential Attribution [1971], p.193) |
11181 | Aristotelian essentialism involves a 'natural' or 'causal' interpretation of modal operators [Marcus (Barcan)] |
Full Idea: Aristotelian essentialism may best be understood on a 'natural' or 'causal' interpretation of the modal operators. | |
From: Ruth Barcan Marcus (Essential Attribution [1971], p.189) | |
A reaction: I record this because I very much like the sound of it, though I have yet to fully understand it. |
11180 | Essentialist sentences are not theorems of modal logic, and can even be false [Marcus (Barcan)] |
Full Idea: In the range of modal systems for which Saul Kripke has provided a semantics, no essentialist sentence is a theorem. Furthermore, there are models for which such sentences are demonstrably false. | |
From: Ruth Barcan Marcus (Essential Attribution [1971], p.188) |
11186 | 'Essentially' won't replace 'necessarily' for vacuous properties like snub-nosed or self-identical [Marcus (Barcan)] |
Full Idea: We would never use 'is essentially' for 'is necessarily' where vacuous properties are concerned, as in 'Socrates is essentially snub-nosed' or 'Socrates is essentially Socrates'. | |
From: Ruth Barcan Marcus (Essential Attribution [1971], p.193) | |
A reaction: This simple point does us a huge service in rescuing the word 'essential' from several hundred years of misguided philosophy. |
11185 | 'Is essentially' has a different meaning from 'is necessarily', as they often cannot be substituted [Marcus (Barcan)] |
Full Idea: There seems to be surface synonymy between 'is essentially' and de re occurrences of 'is necessarily', but intersubstitution often fails to preserve sense (as in 'Winston is essentially a cyclist' and 'Winston is necessarily a cyclist'). | |
From: Ruth Barcan Marcus (Essential Attribution [1971], p.193) | |
A reaction: Clearly the two sentences have different meanings, with 'essentially' being a comment about the nature of Winston, and 'necessarily' probably being a comment about the circumstances in which he finds himself. Very nice. See also Idea 11186. |
11182 | If essences are objects with only essential properties, they are elusive in possible worlds [Marcus (Barcan)] |
Full Idea: Some philosophers make a metaphysical shift, by inventing objects (individual concepts, forms, substances) called 'essences', which have only essential properties, and then worry when they can't locate them by rummaging around in possible worlds. | |
From: Ruth Barcan Marcus (Essential Attribution [1971], p.192) |
11183 | The use of possible worlds is to sort properties (not to individuate objects) [Marcus (Barcan)] |
Full Idea: The usefulness of talk about possible worlds is not for purposes of individuating the object - that can be done in this world; such talk is a way of sorting its properties. | |
From: Ruth Barcan Marcus (Essential Attribution [1971], p.192) | |
A reaction: 'Possible worlds are a device for sorting properties' sounds to me like a promising slogan. Ruth Marcus originated rigid designation, before Kripke came up with the label. |
11187 | In possible worlds, names are just neutral unvarying pegs for truths and predicates [Marcus (Barcan)] |
Full Idea: The strategem of talk about possible worlds is that truth assignments of sentences and extensions of predicates may vary, but individual names don't alter their reference (unless they don't refer). They are a neutral peg for descriptions. | |
From: Ruth Barcan Marcus (Essential Attribution [1971], p.194) |
3102 | Why don't we experience or remember going to sleep at night? [Magee] |
Full Idea: As a child it was incomprehensible to me that I did not experience going to sleep, and never remembered it. When my sister said 'Nobody remembers that', I just thought 'How does she know?' | |
From: Bryan Magee (Confessions of a Philosopher [1997], Ch.I) | |
A reaction: This is actually evidence for something - that we do not have some sort of personal identity which is separate from consciousness, so that "I am conscious" would literally mean that an item has a property, which it can lose. |
11189 | Dispositional essences are special, as if an object loses them they cease to exist [Marcus (Barcan)] |
Full Idea: Being gold or being a man is not accidental. ..Such essences are dispositional properties of a very special kind: if an object had such a property and ceased to have it, it would have ceased to exist or have changed (as if gold is transmuted to lead). | |
From: Ruth Barcan Marcus (Essential Attribution [1971], p.202) | |
A reaction: Ruth Marcus is an important founder of modern scientific essentialism, by not only proposing the notion we call rigid designation, but by explicitly defending the essential identities that seem to emerge from modal logic. |