4 ideas
| 13007 | Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz] |
| Full Idea: Archimedes gave a sort of definition of 'straight line' when he said it is the shortest line between two points. | |
| From: report of Archimedes (fragments/reports [c.240 BCE]) by Gottfried Leibniz - New Essays on Human Understanding 4.13 | |
| A reaction: Commentators observe that this reduces the purity of the original Euclidean axioms, because it involves distance and measurement, which are absent from the purest geometry. |
| 6901 | Understanding is needed for imagination, just as much as the other way around [Betteridge] |
| Full Idea: Although it might be right to say that imagination is required in order to make reasoning and understanding possible, this also works the other way, as imagination cannot occur without some prior understanding. | |
| From: Alex Betteridge (talk [2005]), quoted by PG - Db (ideas) | |
| A reaction: This strikes me as a very illuminating remark, particularly for anyone who aspires to draw a simplified flowdiagram of the mind showing logical priority between its various parts. In fact, the parts are interdependent. Maybe imagination is understanding. |
| 7441 | Experiences are defined by their causal role, and causal roles belong to physical states [Lewis] |
| Full Idea: The definitive characteristic of any experience is its causal role, its most typical causes and effects; but we materialists believe that these causal roles which belong by analytic necessity to experiences belong in fact to certain physical states. | |
| From: David Lewis (An Argument for the Identity Theory [1966], §I) | |
| A reaction: This is the Causal version of functionalism, which Armstrong also developed. The word 'typical' leads later to a teleological element in the theory (e.g. in Lycan). There are other things to say about mental states than just their causal role. |
| 7442 | 'Pain' contingently names the state that occupies the causal role of pain [Lewis] |
| Full Idea: On my theory, 'pain' is a contingent name - that is, a name with different denotations in different possible worlds - since in any world, 'pain' names whatever state happens in that world to occupy the causal role definitive of pain. | |
| From: David Lewis (An Argument for the Identity Theory [1966], §II n6) | |
| A reaction: Better to say that 'pain' (like 'sound') is ambiguous. It is indiscriminately used by English-speakers to mean [1] the raw quale that we experience when damaged, and [2] whatever it is that leads to pain behaviour. Maybe frogs have 2 but not 1. |