6 ideas
| 17743 | De Morgan introduced a 'universe of discourse', to replace Boole's universe of 'all things' [De Morgan, by Walicki] |
| Full Idea: In 1846 De Morgan introduced the enormously influential notion of a possibly arbitrary and stipulated 'universe of discourse'. It replaced Boole's original - and metaphysically a bit suspect - universe of 'all things'. | |
| From: report of Augustus De Morgan (works [1846]) by Michal Walicki - Introduction to Mathematical Logic History D.1.1 | |
| A reaction: This not only brings formal logic under control, but also reflects normal talk, because there is always an explicit or implicit domain of discourse when we talk. Of virtually any conversation, you can say what it is 'about'. |
| 3644 | Two things being joined together doesn't prove they are the same [Descartes] |
| Full Idea: The fact that we often see two things joined together does not license the inference that they are one and the same. | |
| From: René Descartes (Reply to Sixth Objections [1641], 444) | |
| A reaction: Correct. The problem comes when they are never ever apart, and you begin to suspect that they are conjoined in all possible worlds. Why might this be so? It can only be identity or a causal link. |
| 10414 | Abstract objects are constituted by encoded collections of properties [Zalta, by Swoyer] |
| Full Idea: In Zalta's view abstract objects are correlated with collections of properties. ..They encode, as well as exemplify, properties; indeed, an abstract object (such as a Euclidean triangle) is constituted by the properties it encodes. | |
| From: report of Edward N. Zalta (Abstract Objects:intro to Axiomatic Metaphysics [1983]) by Chris Swoyer - Properties 6.3 | |
| A reaction: If we are going to explain abstract objects with properties, then properties had better not be abstract objects. Zalta has a promising idea if we start from a nominalist and naturalistic view of properties (built from physical powers). 'Encode'? |
| 10415 | Properties make round squares and round triangles distinct, unlike exemplification [Zalta, by Swoyer] |
| Full Idea: On Zalta's view, properties with the same encoding extensions are identical, but may be distinct with the same exemplification extension. So the properties of being a round square and a round triangle are distinct, but with the same exemplification. | |
| From: report of Edward N. Zalta (Abstract Objects:intro to Axiomatic Metaphysics [1983]) by Chris Swoyer - Properties | |
| A reaction: (For Zalta's view, see Idea 10414) I'm not sure about 'encoding' (cf. Hodes's use of the word), but the idea that an abstract object is just a bunch of possible properties (assuming properties have prior availability) seems promising. |
| 3621 | Only judgement decides which of our senses are reliable [Descartes] |
| Full Idea: Sense alone does not suffice to correct visual error: we also need a degree of reason to tell us that we should believe the judgement based on touch rather than vision. Since we don't have this power in infancy, it must be attributed to the intellect. | |
| From: René Descartes (Reply to Sixth Objections [1641], 439) |
| 3637 | Ideas in God's mind only have value if he makes it so [Descartes] |
| Full Idea: It is impossible to imagine that anything is thought of in the divine intellect as good or true, or worthy of belief or action or omission, prior to the decision of the divine will to make it so. | |
| From: René Descartes (Reply to Sixth Objections [1641], 432) |