4 ideas
| 17743 | De Morgan introduced a 'universe of discourse', to replace Boole's universe of 'all things' [De Morgan, by Walicki] |
| Full Idea: In 1846 De Morgan introduced the enormously influential notion of a possibly arbitrary and stipulated 'universe of discourse'. It replaced Boole's original - and metaphysically a bit suspect - universe of 'all things'. | |
| From: report of Augustus De Morgan (works [1846]) by Michal Walicki - Introduction to Mathematical Logic History D.1.1 | |
| A reaction: This not only brings formal logic under control, but also reflects normal talk, because there is always an explicit or implicit domain of discourse when we talk. Of virtually any conversation, you can say what it is 'about'. |
| 4038 | Properties are sets of their possible instances (which separates 'renate' from 'cordate') [Lewis, by Mellor/Oliver] |
| Full Idea: Lewis agrees that properties cannot be sets of their actual instances, but claims they can be sets of their possible instances. This would distinguish coextensive properties like being cordate and renate, since they might be separated. | |
| From: report of David Lewis (Modal Realism at Work: Properties [1986]) by DH Mellor / A Oliver - Introduction to 'Properties' §10 | |
| A reaction: Sounds wrong. Two properties could be obviously different even if they could never be separated. In this world a creature might briefly survive without kidneys. |
| 19696 | There are reasons 'for which' a belief is held, reasons 'why' it is believed, and reasons 'to' believe it [Neta] |
| Full Idea: We must distinguish between something's being a 'reason for which' a creature believes something, and its being a 'reason why' a creature believes something. ...We must also distinguish a 'reason for which' from a 'reason to' believe something. | |
| From: Ram Neta (The Basing Relation [2011], Intro) | |
| A reaction: He doesn't spell the distinctions out clearly. I take it that 'for which' is my personal justification, 'why' is the dodgy prejudices that cause my belief. and 'to' is some actual good reasons, of which I may be unaware. |
| 19697 | The basing relation of a reason to a belief should both support and explain the belief [Neta] |
| Full Idea: A reason has a 'basing relation' with a belief if it (i) rationally supports holding the belief, and (ii) explains why the belief is held. | |
| From: Ram Neta (The Basing Relation [2011], Intro) | |
| A reaction: Presumably a false reason would fit this account. Why not talk of 'grounding', or is that word now reserved for metaphysics? If I hypnotise you into a belief, would my hypnotic power be the basing reason? Fits (ii), but not (i). |