Combining Texts

All the ideas for 'works', 'Letters to Russell' and 'De Cive'

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5 ideas

6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
I wish to go straight from cardinals to reals (as ratios), leaving out the rationals [Frege]
     Full Idea: You need a double transition, from cardinal numbes (Anzahlen) to the rational numbers, and from the latter to the real numbers generally. I wish to go straight from the cardinal numbers to the real numbers as ratios of quantities.
     From: Gottlob Frege (Letters to Russell [1902], 1903.05.21), quoted by Michael Dummett - Frege philosophy of mathematics 21 'Frege's'
     A reaction: Note that Frege's real numbers are not quantities, but ratios of quantities. In this way the same real number can refer to lengths, masses, intensities etc.
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
The loss of my Rule V seems to make foundations for arithmetic impossible [Frege]
     Full Idea: With the loss of my Rule V, not only the foundations of arithmetic, but also the sole possible foundations of arithmetic, seem to vanish.
     From: Gottlob Frege (Letters to Russell [1902], 1902.06.22)
     A reaction: Obviously he was stressed, but did he really mean that there could be no foundation for arithmetic, suggesting that the subject might vanish into thin air?
9. Objects / A. Existence of Objects / 2. Abstract Objects / c. Modern abstracta
Logical objects are extensions of concepts, or ranges of values of functions [Frege]
     Full Idea: How are we to conceive of logical objects? My only answer is, we conceive of them as extensions of concepts or, more generally, as ranges of values of functions ...what other way is there?
     From: Gottlob Frege (Letters to Russell [1902], 1902.07.28), quoted by J. Alberto Coffa - The Semantic Tradition from Kant to Carnap 7 epigr
     A reaction: This is the clearest statement I have found of what Frege means by an 'object'. But an extension is a collection of things, so an object is a group treated as a unity, which is generally how we understand a 'set'. Hence Quine's ontology.
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature
The most important aspect of a human being is not reason, but passion [Kierkegaard, by Carlisle]
     Full Idea: Kierkegaard insisted that the most important aspect of a human being is not reason, but passion.
     From: report of Søren Kierkegaard (works [1845]) by Clare Carlisle - Kierkegaard: a guide for the perplexed Intro
     A reaction: Hume comes to mind for a similar view, but in character Hume was far more rational than Kierkegaard.
25. Social Practice / E. Policies / 1. War / c. Combatants
I act justly if I follow my Prince in an apparently unjust war, and refusing to fight would be injustice [Hobbes]
     Full Idea: If I wage war at the commandment of my Prince, conceiving the war to be justly undertaken, I do not therefore do unjustly, but rather if I refuse to do it, arrogating to myself the knowledge of what is just and unjust, which pertains only to my Prince.
     From: Thomas Hobbes (De Cive [1642], 12.II), quoted by Jeff McMahan - Killing in War 2.6
     A reaction: Hobbes early says that Princes make things just by commanding them. This presumably assumes divine authority in the Prince. This is, of course, ancient pernicious nonsense.