8 ideas
| 8964 | Entities can be multiplied either by excessive categories, or excessive entities within a category [Hoffman/Rosenkrantz] |
| Full Idea: There are two ways that entities can be multiplied unnecessarily: by multiplying the number of explanatory categories, and by multiplying the number of entities within a category. | |
| From: J Hoffman/G Rosenkrantz (Platonistic Theories of Universals [2003], 4) | |
| A reaction: An important distinction. The orthodox view is that it is the excess of categories that is to be avoided (e.g. by nominalists). Possible worlds in metaphysics, and multiple worlds in physics, claim not to violate the first case. |
| 21558 | 'Predicative' norms are those which define a class [Russell] |
| Full Idea: Norms (containing one variable) which do not define classes I propose to call 'non-predicative'; those which do define classes I shall call 'predicative'. | |
| From: Bertrand Russell (Difficulties of Transfinite Numbers and Types [1905], p.141) |
| 21559 | We need rules for deciding which norms are predicative (unless none of them are) [Russell] |
| Full Idea: We need rules for deciding what norms are predicative and what are not, unless we adopt the view (which has much to recommend it) that no norms are predicative. ...[146] A predative propositional function is one which determines a class. | |
| From: Bertrand Russell (Difficulties of Transfinite Numbers and Types [1905], p.141) | |
| A reaction: He is referring to his 'no class' theory, which he favoured at that time. |
| 8962 | 'There are shapes which are never exemplified' is the toughest example for nominalists [Hoffman/Rosenkrantz] |
| Full Idea: The example which presents the most serious challenge to nominalism is 'there are shapes which are never exemplified'. | |
| From: J Hoffman/G Rosenkrantz (Platonistic Theories of Universals [2003], 3) | |
| A reaction: To 'exemplify' a shape must it be a physical object, or a drawing of such an object, or a description? If none of those have ever existed, I'm not sure what 'are' is supposed to mean. They seem to be possibilia (with all the associated problems). |
| 8961 | Nominalists are motivated by Ockham's Razor and a distrust of unobservables [Hoffman/Rosenkrantz] |
| Full Idea: The two main motivations for nominalism are an admirable commitment to Ockham's Razor, and a queasiness about postulating entities that are unobservable or non-empirical, existing in a non-physical realm. | |
| From: J Hoffman/G Rosenkrantz (Platonistic Theories of Universals [2003], 3) | |
| A reaction: It doesn't follow that because the entities are unobservable that they are non-physical. Consider the 'interior' of an electron. Neverless I share a love of Ockham's Razor and a deep caution about unobservables. |
| 8963 | Four theories of possible worlds: conceptualist, combinatorial, abstract, or concrete [Hoffman/Rosenkrantz] |
| Full Idea: There are four models of the ontological status of possible worlds: conceptualist (mental constructions), combinatorial (all combinations of the actual world), abstract worlds (conjunction of propositions), and concrete worlds (collections of concreta). | |
| From: J Hoffman/G Rosenkrantz (Platonistic Theories of Universals [2003], 4) | |
| A reaction: [the proponents cited are, in order, Rescher, Cresswell, Plantinga and Lewis] They dismiss Rescher and Cresswell, both of whom seem to me more plausible than Plantinga or Lewis. 'Possible' can't figure in the definition. Possible to us, or in reality? |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
| From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
| A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
| From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
| A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |