3 ideas
| 7803 | Modal logic began with translation difficulties for 'If...then' [Lewis,CI, by Girle] |
| Full Idea: C.I.Lewis began his groundbreaking work in modal logic because he was concerned about the unreliability of the material conditional as a translation of 'If ... then' conditionals. | |
| From: report of C.I. Lewis (Symbolic Logic (with Langford) [1932]) by Rod Girle - Modal Logics and Philosophy 12.3 | |
| A reaction: Compare 'if this is square then it has four corners' with 'if it rains then our afternoon is ruined'. Different modalities seem to be involved. We even find that 'a square has four corners' will be materially implied if it rains! |
| 3284 | There is no one theory of how to act (or what to believe) [Nagel] |
| Full Idea: To look for a single general theory of how to decide the right thing to do is like looking for a single theory of how to decide what to believe. | |
| From: Thomas Nagel (The Fragmentation of Value [1977], p.135) | |
| A reaction: Depends on your level of generality. Values and virtues are general guides which should be brought to every action, with 'higher' values guiding choice of what is relevant. |
| 19399 | Prime matter is nothing when it is at rest [Leibniz] |
| Full Idea: Primary matter is nothing if considered at rest. | |
| From: Gottfried Leibniz (Aristotle and Descartes on Matter [1671], p.90) | |
| A reaction: This goes with Leibniz's Idea 13393, that activity is the hallmark of existence. No one seems to have been able to make good sense of prime matter, and it plays little role in Aristotle's writings. |