Combining Texts

Ideas for 'Parmenides', 'A Problem about Substitutional Quantification?' and 'Philebus'

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3 ideas

6. Mathematics / A. Nature of Mathematics / 2. Geometry
It is absurd to define a circle, but not be able to recognise a real one [Plato]
     Full Idea: It will be ridiculous if our student knows the definition of the circle and of the divine sphere itself, but cannot recognize the human sphere and these our circles, used in housebuilding.
     From: Plato (Philebus [c.353 BCE], 62a)
     A reaction: This is the equivalent of being able to recite numbers, but not to count objects. It also resembles Molyneux's question (to Locke), of whether recognition by one sense entails recognition by others. Nice (and a bit anti-platonist!).
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / f. Arithmetic
Daily arithmetic counts unequal things, but pure arithmetic equalises them [Plato]
     Full Idea: The arithmetic of the many computes sums of unequal units, such as two armies, or two herds, ..but philosopher's arithmetic computes when it is guaranteed that none of those infinitely many units differed in the least from any of the others.
     From: Plato (Philebus [c.353 BCE], 56d)
     A reaction: But of course 'the many' are ironing out the differences too, when they say there are 'three armies'. Shocking snob, Plato. Even philosophers are interested in the difference between three armies and three platoons.
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / a. For mathematical platonism
One is, so numbers exist, so endless numbers exist, and each one must partake of being [Plato]
     Full Idea: If one is, there must also necessarily be number - Necessarily - But if there is number, there would be many, and an unlimited multitude of beings. ..So if all partakes of being, each part of number would also partake of it.
     From: Plato (Parmenides [c.364 BCE], 144a)
     A reaction: This seems to commit to numbers having being, then to too many numbers, and hence to too much being - but without backing down and wondering whether numbers had being after all. Aristotle disagreed.