display all the ideas for this combination of texts
3 ideas
| 5395 | Demonstration always relies on the rule that anything implied by a truth is true [Russell] |
| Full Idea: All demonstrations involve the principle that 'anything implied by a true proposition is true', or 'whatever follows from a true proposition is true'. | |
| From: Bertrand Russell (Problems of Philosophy [1912], Ch. 7) | |
| A reaction: This is modus ponens, a broad principle of rationality, rather than of strict logicality, because it covers practical inferences and vague propositions. Presumably truth is a prior concept to implication, and therefore more metaphysically basic. |
| 5386 | Proper names are really descriptions, and can be replaced by a description in a person's mind [Russell] |
| Full Idea: Common words, even proper names, are usually really descriptions; that is, the thought in the mind of a person using a proper name correctly can generally only be expressed explicitly if we replace the proper name by a description. | |
| From: Bertrand Russell (Problems of Philosophy [1912], Ch. 5) | |
| A reaction: This is open to challenge, and the modern idea is that they are more like baptisms, but it all comes down to the debate about internal and external content. Russell would appear to be voicing the internalist theory of names. |
| 5385 | The phrase 'a so-and-so' is an 'ambiguous' description'; 'the so-and-so' (singular) is a 'definite' description [Russell] |
| Full Idea: A phrase of the form 'a so-and-so' I shall call an 'ambiguous' description, and a phrase of the form 'the so-and-so' (in the singular) I shall call a 'definite' description. | |
| From: Bertrand Russell (Problems of Philosophy [1912], Ch. 5) | |
| A reaction: This leaves the problem of those definite descriptions which succeed in referring ('the present Prime Minister'), those which haven't succeeded yet ('the person who will get the most votes'), and those which won't refer ('the present King of France'). |