6 ideas
| 10196 | The Axiom of Choice needs a criterion of choice [Black] |
| Full Idea: Some mathematicians seem to think that talk of an Axiom of Choice allows them to choose a single member of a collection when there is no criterion of choice. | |
| From: Max Black (The Identity of Indiscernibles [1952], p.68) |
| 10194 | Two things can only be distinguished by a distinct property or a distinct relation [Black] |
| Full Idea: The only way we can discover that two things exist is by finding out that one has a quality not possessed by the other, or else that one has a relational characteristic that the other hasn't. | |
| From: Max Black (The Identity of Indiscernibles [1952], p.67) | |
| A reaction: At least this doesn't conflate relations with properties. Note that this idea is clearly epistemological, and in no way rules out the separateness of two objects which none of us can ever discern. Maybe the Earth has two Suns, which imperceptibly swap. |
| 12251 | Substantial forms are not understood, and explain nothing [Descartes] |
| Full Idea: Clearly no explanation can be given by these substantial forms for any natural action, since their defenders admit that they are occult and that they do not understand them themselves, ...so they explain nothing. | |
| From: René Descartes (Letters to Regius [1642], 1642.01), quoted by David S. Oderberg - Real Essentialism 267 n5 | |
| A reaction: [Oderberg gives refs for attack by Locke and Hume, p.66] Descartes' target is Aristotle's hylomorphism. The problem seems to be understanding what Aristotle meant, which is much more than mere 'shape'. More like 'controlling principle'. |
| 10193 | The 'property' of self-identity is uselessly tautological [Black] |
| Full Idea: Saying that 'a has the property of being identical with a' is a roundabout way of saying nothing - a useless tautology - and means not more than 'a is a' | |
| From: Max Black (The Identity of Indiscernibles [1952], p.66) | |
| A reaction: This matter resembles the problem of the number zero, and the empty set, which seem to be crucial entities for logicians, but of no interest to a common sense view of the world. So much the worse for logic, I am inclined to say. |
| 10195 | If the universe just held two indiscernibles spheres, that refutes the Identity of Indiscernibles [Black] |
| Full Idea: Isn't it logically possible that the universe should have contained nothing but two exactly similar spheres? ...So two things would have all their properties in common, and this would refute the Principle of the Identity of Indiscernibles. | |
| From: Max Black (The Identity of Indiscernibles [1952], p.67) | |
| A reaction: [Black is the originator of this famous example] It also appears to be naturally possible. An observer at an instant of viewing will discern a relational difference relative to themselves. Most people take Black's objection to be decisive. |
| 16772 | An angelic mind would not experience pain, even when connected to a human body [Descartes, by Pasnau] |
| Full Idea: Descartes points out that an angelic mind, even if causally connected to a human body, would not experience the same sort of bodily sensations; it would, instead, simply observe flesh being torn, like a piece of paper. | |
| From: report of René Descartes (Letters to Regius [1642], III:493) by Robert Pasnau - Metaphysical Themes 1274-1671 25.6 | |
| A reaction: Does that mean that the angel could not have the experience even if it wanted to have it. So they can't pick up a cup either? So they can't make themselves known to us, even if they are desperate to? So the Annunciation never happened? |