Combining Texts

All the ideas for 'works', 'The Search After Truth' and 'On the Concept of Number'

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4 ideas

5. Theory of Logic / G. Quantification / 2. Domain of Quantification
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'.
6. Mathematics / C. Sources of Mathematics / 7. Formalism
22293 Hilbert said (to block paradoxes) that mathematical existence is entailed by consistency [Hilbert, by Potter]
     Full Idea: Hilbert proposed to circuvent the paradoxes by means of the doctrine (already proposed by Poincaré) that in mathematics consistency entails existence.
     From: report of David Hilbert (On the Concept of Number [1900], p.183) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 19 'Exist'
     A reaction: Interesting. Hilbert's idea has struck me as weird, but it makes sense if its main motive is to block the paradoxes. Roughly, the idea is 'it exists if it isn't paradoxical'. A low bar for existence (but then it is only in mathematics!).
8. Modes of Existence / B. Properties / 8. Properties as Modes
16669 Everything that exists is either a being, or some mode of a being [Malebranche]
     Full Idea: It is absolutely necessary that everything in the world be either a being or a mode [manière] of a being.
     From: Nicolas Malebranche (The Search After Truth [1675], III.2.8.ii), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 13.4
26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity
12726 In a true cause we see a necessary connection [Malebranche]
     Full Idea: A true cause is one in which the mind perceives a necessary connection between the cause and its effect.
     From: Nicolas Malebranche (The Search After Truth [1675], 1.649 (450)), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 5
     A reaction: Presumably Hume was ignorant of 'true' causes, since he says he never saw this connection. But then is the perception done by the mind, or by the senses?