display all the ideas for this combination of philosophers
3 ideas
13543 | A relation is not reflexive, just because it is transitive and symmetrical [Bostock] |
Full Idea: It is easy to fall into the error of supposing that a relation which is both transitive and symmetrical must also be reflexive. | |
From: David Bostock (Intermediate Logic [1997], 4.7) | |
A reaction: Compare Idea 14430! Transivity will take you there, and symmetricality will get you back, but that doesn't entitle you to take the shortcut? |
13802 | Relations can be one-many (at most one on the left) or many-one (at most one on the right) [Bostock] |
Full Idea: A relation is 'one-many' if for anything on the right there is at most one on the left (∀xyz(Rxz∧Ryz→x=y), and is 'many-one' if for anything on the left there is at most one on the right (∀xyz(Rzx∧Rzy→x=y). | |
From: David Bostock (Intermediate Logic [1997], 8.1) |
17619 | We renounce all abstract entities [Goodman/Quine] |
Full Idea: We do not believe in abstract entities..... We renounce them altogether. | |
From: Goodman,N/Quine,W (Steps Towards a Constructive Nominalism [1947], p.105), quoted by Penelope Maddy - Defending the Axioms | |
A reaction: Goodman always kept the faith here, but Quine decided to embrace sets, as a minimal commitment to abstracta needed for mathematics, which was needed for science. My sympathies are with Goodman. This is the modern form of 'nominalism'. |