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All the ideas for 'Defending the Axioms', 'On Multiplying Entities' and 'Reflections on Value'

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17 ideas

1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
All thought about values is philosophical, and thought about anything else is not philosophy [Weil]
     Full Idea: All reflections bearing on the notion of value and on the hierarchy of values is philosophical; all efforts of thought bearing on anything other than value are, if one examines them closely, foreign to philosophy.
     From: Simone Weil (Reflections on Value [1941], p.30)
     A reaction: If nothing else proves that Weil is a platonist, this does. She, of course, has a transcendent and religious view of values, whereas I just see them as concepts which embody what is important. That said, I'm not far off agreeing with this.
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / b. Philosophy as transcendent
Philosophy aims to change the soul, not to accumulate knowledge [Weil]
     Full Idea: Philosophy does not consist in accumulating knowledge, as science does, but in changing the whole soul.
     From: Simone Weil (Reflections on Value [1941], p.33)
     A reaction: I agree, roughly. In the sense that philosophy is a much more personal matter than any pure pursuit of knowledge, such as geology. Though a life in geology could change your soul. Not just any old change, of course….
1. Philosophy / E. Nature of Metaphysics / 3. Metaphysical Systems
Systems are not unique to each philosopher. The platonist tradition is old and continuous [Weil]
     Full Idea: People believe that every philosopher has a system that contradicts all the others! But there is a tradition, genuinely philosophical, that is as old as humanity itself. …Plato is the most perfect representative of this tradition.
     From: Simone Weil (Reflections on Value [1941], p.33)
     A reaction: I see roughly two traditions. If you believe in transcendence you follow Plato, like Simone. If you are a naturalist (like me) you follow Aristotle. A third tradition might be much more sceptical.
2. Reason / B. Laws of Thought / 6. Ockham's Razor
The quest for simplicity drove scientists to posit new entities, such as molecules in gases [Quine]
     Full Idea: It is the quest for system and simplicity that has kept driving the scientist to posit further entities as values of his variables. By positing molecules, Boyles' law of gases could be assimilated into a general theory of bodies in motion.
     From: Willard Quine (On Multiplying Entities [1974], p.262)
     A reaction: Interesting that a desire for simplicity might lead to multiplications of entities. In fact, I presume molecules had been proposed elsewhere in science, and were adopted in gas-theory because they were thought to exist, not because simplicity is nice.
In arithmetic, ratios, negatives, irrationals and imaginaries were created in order to generalise [Quine]
     Full Idea: In classical arithmetic, ratios were posited to make division generally applicable, negative numbers to make subtraction generally applicable, and irrationals and finally imaginaries to make exponentiation generally applicable.
     From: Willard Quine (On Multiplying Entities [1974], p.263)
     A reaction: This is part of Quine's proposal (c.f. Idea 8207) that entities have to be multiplied in order to produce simplicity. He is speculating. Maybe they are proposed because they are just obvious, and the generality is a nice side-effect.
3. Truth / A. Truth Problems / 1. Truth
Truth is a value of thought [Weil]
     Full Idea: Truth is a value of thought. The word 'truth' cannot have any other meaning.
     From: Simone Weil (Reflections on Value [1941], p.32)
     A reaction: This makes a nice change from truth being a mere predicate. I would call truth the criterion of success in thought, and that counts as a value, so she is right.
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The Axiom of Choice paradoxically allows decomposing a sphere into two identical spheres [Maddy]
     Full Idea: One feature of the Axiom of Choice that troubled many mathematicians was the so-called Banach-Tarski paradox: using the Axiom, a sphere can be decomposed into finitely many parts and those parts reassembled into two spheres the same size as the original.
     From: Penelope Maddy (Defending the Axioms [2011], 1.3)
     A reaction: (The key is that the parts are non-measurable). To an outsider it is puzzling that the Axiom has been universally accepted, even though it produces such a result. Someone can explain that, I'm sure.
5. Theory of Logic / C. Ontology of Logic / 3. If-Thenism
Critics of if-thenism say that not all starting points, even consistent ones, are worth studying [Maddy]
     Full Idea: If-thenism denies that mathematics is in the business of discovering truths about abstracta. ...[their opponents] obviously don't regard any starting point, even a consistent one, as equally worthy of investigation.
     From: Penelope Maddy (Defending the Axioms [2011], 3.3)
     A reaction: I have some sympathy with if-thenism, in that you can obviously study the implications of any 'if' you like, but deep down I agree with the critics.
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Hilbert's geometry and Dedekind's real numbers were role models for axiomatization [Maddy]
     Full Idea: At the end of the nineteenth century there was a renewed emphasis on rigor, the central tool of which was axiomatization, along the lines of Hilbert's axioms for geometry and Dedekind's axioms for real numbers.
     From: Penelope Maddy (Defending the Axioms [2011], 1.3)
If two mathematical themes coincide, that suggest a single deep truth [Maddy]
     Full Idea: The fact that two apparently fruitful mathematical themes turn out to coincide makes it all the more likely that they're tracking a genuine strain of mathematical depth.
     From: Penelope Maddy (Defending the Axioms [2011], 5.3ii)
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / g. Continuum Hypothesis
Every infinite set of reals is either countable or of the same size as the full set of reals [Maddy]
     Full Idea: One form of the Continuum Hypothesis is the claim that every infinite set of reals is either countable or of the same size as the full set of reals.
     From: Penelope Maddy (Defending the Axioms [2011], 2.4 n40)
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Set-theory tracks the contours of mathematical depth and fruitfulness [Maddy]
     Full Idea: Our set-theoretic methods track the underlying contours of mathematical depth. ...What sets are, most fundamentally, is markers for these contours ...they are maximally effective trackers of certain trains of mathematical fruitfulness.
     From: Penelope Maddy (Defending the Axioms [2011], 3.4)
     A reaction: This seems to make it more like a map of mathematics than the actual essence of mathematics.
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / c. Against mathematical empiricism
The connection of arithmetic to perception has been idealised away in modern infinitary mathematics [Maddy]
     Full Idea: Ordinary perceptual cognition is most likely involved in our grasp of elementary arithmetic, but ...this connection to the physical world has long since been idealized away in the infinitary structures of contemporary pure mathematics.
     From: Penelope Maddy (Defending the Axioms [2011], 2.3)
     A reaction: Despite this, Maddy's quest is for a 'naturalistic' account of mathematics. She ends up defending 'objectivity' (and invoking Tyler Burge), rather than even modest realism. You can't 'idealise away' the counting of objects. I blame Cantor.
7. Existence / B. Change in Existence / 4. Events / c. Reduction of events
Explaining events just by bodies can't explain two events identical in space-time [Quine]
     Full Idea: An account of events just in terms of physical bodies does not distinguish between events that happen to take up just the same portion of space-time. A man's whistling and walking would be identified with the same temporal segment of the man.
     From: Willard Quine (On Multiplying Entities [1974], p.260)
     A reaction: We wouldn't want to make his 'walking' and his 'strolling' two events. Whistling and walking are different because different objects are involved (lips and legs). Hence a man is not (ontologically) a single object.
10. Modality / A. Necessity / 11. Denial of Necessity
Necessity could be just generalisation over classes, or (maybe) quantifying over possibilia [Quine]
     Full Idea: The need to add a note of necessity to 'all black crows are black' could be met by a generalisation over classes (what belongs to sets x and y belongs to y), or maybe be quantifying over possible particulars.
     From: Willard Quine (On Multiplying Entities [1974], p.262)
     A reaction: He dislikes the second strategy because 'unactualized particulars are an obscure and troublesome lot'. The second is the strategy of Lewis. I think necessity starts to creep back in as soon as you ask WHY a generalisation holds true.
22. Metaethics / B. Value / 1. Nature of Value / e. Means and ends
Ends, unlike means, cannot be defined, which is why people tend to pursue means [Weil]
     Full Idea: Everything that can be taken as an end cannot be defined. Means, such as power and money, are easily defined, and that is why people orient themselves exclusively towards the acquisition of means.
     From: Simone Weil (Reflections on Value [1941], p.31)
     A reaction: Nice, but too neat, because so many activities can be treated either as means or as ends, and often as both. It makes sense that people pursue what is clear to them.
22. Metaethics / B. Value / 2. Values / a. Normativity
Minds essentially and always strive towards value [Weil]
     Full Idea: For the mind essentially and always, in whatever manner it is disposed, strives towards value.
     From: Simone Weil (Reflections on Value [1941], p.31)
     A reaction: A typically platonist thought. If you accept my view that values identify what is important, the thought is plausible. We might distinguish between what the mind pointlessly entertains, and what it 'strives' for.