8 ideas
| 17699 | Variables are auxiliary notions, and not part of the 'eternal' essence of logic [Schönfinkel] |
| Full Idea: A variable in a proposition of logic ....has the status of a mere auxiliary notion that is really inappropriate to the constant, 'eternal' essence of the propositions of logic. | |
| From: Moses Schönfinkel (Building Blocks of Mathematical Logic [1924], §1) | |
| A reaction: He presumably thinks that what the variables stand for (and he mentions 'argument places' and 'operators') will be included in the essence. My attention was caught by the thought that he takes logic to have an essence. |
| 13795 | Properties only have identity in the context of their contraries [Elder] |
| Full Idea: The very being, the identity, of any property consists at least in part in its contrasting as it does with its own proper contraries. | |
| From: Crawford L. Elder (Real Natures and Familiar Objects [2004], 2.4) | |
| A reaction: See Elder for the details of this, but the idea that properties can only be individuated contextually sounds promising. |
| 13798 | Maybe we should give up the statue [Elder] |
| Full Idea: Some contemporary metaphysicians infer that one of the objects must go, namely, the statue. | |
| From: Crawford L. Elder (Real Natures and Familiar Objects [2004], 7.2) | |
| A reaction: [He cites Zimmerman 1995] This looks like a recipe for creating a vast gulf between philosophers and the rest of the population. If it is right, it makes the true ontology completely useless in understanding our daily lives. |
| 13797 | The loss of an essential property means the end of an existence [Elder] |
| Full Idea: The loss of any essential property must amount to the end of an existence. | |
| From: Crawford L. Elder (Real Natures and Familiar Objects [2004], 3) | |
| A reaction: This is orthodoxy for essentialists, and I presume that Aristotle would agree, but I have a problem with the essence of a great athlete, who then grows old. Must we say that they lose their identity-as-an-athlete? |
| 13794 | Essential properties by nature occur in clusters or packages [Elder] |
| Full Idea: Essential properties by nature occur in clusters or packages. | |
| From: Crawford L. Elder (Real Natures and Familiar Objects [2004], 2.2) | |
| A reaction: Elder proposes this as his test for the essentialness of a property - his Test of Flanking Uniformities. A nice idea. |
| 13796 | Essential properties are bound together, and would be lost together [Elder] |
| Full Idea: The properties of any essential nature are bound together....[122] so any case in which one of our envisioned familiar objects loses one of its essential properties will be a case in which it loses several. | |
| From: Crawford L. Elder (Real Natures and Familiar Objects [2004], 3) | |
| A reaction: This sounds like a fairly good generalisation rather than a necessary truth. Is there a natural selection for properties, so that only the properties which are able to bind to others to form teams are able to survive and flourish? |
| 13165 | Geometrical proofs do not show causes, as when we prove a triangle contains two right angles [Proclus] |
| Full Idea: Geometry does not ask 'why?' ..When from the exterior angle equalling two opposite interior angles it is shown that the interior angles make two right angles, this is not a causal demonstration. With no exterior angle they still equal two right angles. | |
| From: Proclus (Commentary on Euclid's 'Elements' [c.452], p.161-2), quoted by Paolo Mancosu - Explanation in Mathematics §5 | |
| A reaction: A very nice example. It is hard to imagine how one might demonstrate the cause of the angles making two right angles. If you walk, turn left x°, then turn left y°, then turn left z°, and x+y+z=180°, you end up going in the original direction. |
| 9569 | The origin of geometry started in sensation, then moved to calculation, and then to reason [Proclus] |
| Full Idea: It is unsurprising that geometry was discovered in the necessity of Nile land measurement, since everything in the world of generation goes from imperfection to perfection. They would naturally pass from sense-perception to calculation, and so to reason. | |
| From: Proclus (Commentary on Euclid's 'Elements' [c.452]), quoted by Charles Chihara - A Structural Account of Mathematics 9.12 n55 | |
| A reaction: The last sentence is the core of my view on abstraction, that it proceeds by moving through levels of abstraction, approaching more and more general truths. |