display all the ideas for this combination of texts
5 ideas
| 19444 | Each proposition has an antithesis, and truth exists as its refutation [Feuerbach] |
| Full Idea: Every intellectual determination has its antithesis, its contradiction. Truth exists not in unity with, but in refutation of its opposite. | |
| From: Ludwig Feuerbach (Towards a Critique of Hegel's Philosophy [1839], p.72) | |
| A reaction: This appears to be a rejection of the 'synthesis' in Hegel, in favour of what strikes me as a rather more sensible interpretation of the modern dialectic. Being exists in contrast to nothingness, and truth exists in contrast to its negation? |
| 19445 | A dialectician has to be his own opponent [Feuerbach] |
| Full Idea: A thinker is a dialectician only insofar as he is his own opponent. | |
| From: Ludwig Feuerbach (Towards a Critique of Hegel's Philosophy [1839], p.72) | |
| A reaction: Quite an inspirational slogan for beginners in philosophy. How many non-philosophers are willing to be their own opponent. In law courts and the House of Commons we assign the roles to separate persons. Hence rhetoric replaces reason? |
| 8721 | An 'impredicative' definition seems circular, because it uses the term being defined [Friend] |
| Full Idea: An 'impredicative' definition is one that uses the terms being defined in order to give the definition; in some way the definition is then circular. | |
| From: Michèle Friend (Introducing the Philosophy of Mathematics [2007], Glossary) | |
| A reaction: There has been a big controversy in the philosophy of mathematics over these. Shapiro gives the definition of 'village idiot' (which probably mentions 'village') as an example. |
| 8680 | Classical definitions attempt to refer, but intuitionist/constructivist definitions actually create objects [Friend] |
| Full Idea: In classical logic definitions are thought of as revealing our attempts to refer to objects, ...but for intuitionist or constructivist logics, if our definitions do not uniquely characterize an object, we are not entitled to discuss the object. | |
| From: Michèle Friend (Introducing the Philosophy of Mathematics [2007], 2.4) | |
| A reaction: In defining a chess piece we are obviously creating. In defining a 'tree' we are trying to respond to fact, but the borderlines are vague. Philosophical life would be easier if we were allowed a mixture of creation and fact - so let's have that. |
| 3678 | Reductio ad absurdum proves an idea by showing that its denial produces contradiction [Friend] |
| Full Idea: Reductio ad absurdum arguments are ones that start by denying what one wants to prove. We then prove a contradiction from this 'denied' idea and more reasonable ideas in one's theory, showing that we were wrong in denying what we wanted to prove. | |
| From: Michèle Friend (Introducing the Philosophy of Mathematics [2007], 2.3) | |
| A reaction: This is a mathematical definition, which rests on logical contradiction, but in ordinary life (and philosophy) it would be enough to show that denial led to absurdity, rather than actual contradiction. |