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All the ideas for 'Thinking About Mathematics', 'Human Flourishing, Ethics and Liberty' and 'The Theodicy'

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33 ideas

2. Reason / A. Nature of Reason / 3. Pure Reason
Reasonings have a natural ordering in God's understanding, but only a temporal order in ours [Leibniz]
     Full Idea: All reasonings are eminent in God, and they preserve an order among themselves in his understanding as well as in ours; but for him this is just an order and a priority of nature, whereas for us there is a priority of time.
     From: Gottfried Leibniz (The Theodicy [1710], p.192), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.III
     A reaction: This view is found in Frege, and seems to be the hallmark of rationalist philosophy. There is an apriori assumption that reality has a rational order, so that pure reason is a tool for grasping it. Lewis's 'mosaic' of experiences has no order.
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Intuitionists deny excluded middle, because it is committed to transcendent truth or objects [Shapiro]
     Full Idea: Intuitionists in mathematics deny excluded middle, because it is symptomatic of faith in the transcendent existence of mathematical objects and/or the truth of mathematical statements.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 1.2)
     A reaction: There are other problems with excluded middle, such as vagueness, but on the whole I, as a card-carrying 'realist', am committed to the law of excluded middle.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
The number 3 is presumably identical as a natural, an integer, a rational, a real, and complex [Shapiro]
     Full Idea: It is surely wise to identify the positions in the natural numbers structure with their counterparts in the integer, rational, real and complex number structures.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.2)
     A reaction: The point is that this might be denied, since 3, 3/1, 3.00.., and -3*i^2 are all arrived at by different methods of construction. Natural 3 has a predecessor, but real 3 doesn't. I agree, intuitively, with Shapiro. Russell (1919) disagreed.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / h. Reals from Cauchy
Cauchy gave a formal definition of a converging sequence. [Shapiro]
     Full Idea: A sequence a1,a2,... of rational numbers is 'Cauchy' if for each rational number ε>0 there is a natural number N such that for all natural numbers m, n, if m>N and n>N then -ε < am - an < ε.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 7.2 n4)
     A reaction: The sequence is 'Cauchy' if N exists.
6. Mathematics / B. Foundations for Mathematics / 1. Foundations for Mathematics
Categories are the best foundation for mathematics [Shapiro]
     Full Idea: There is a dedicated contingent who hold that the category of 'categories' is the proper foundation for mathematics.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.3 n7)
     A reaction: He cites Lawvere (1966) and McLarty (1993), the latter presenting the view as a form of structuralism. I would say that the concept of a category will need further explication, and probably reduce to either sets or relations or properties.
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / f. Zermelo numbers
Two definitions of 3 in terms of sets disagree over whether 1 is a member of 3 [Shapiro]
     Full Idea: Zermelo said that for each number n, its successor is the singleton of n, so 3 is {{{null}}}, and 1 is not a member of 3. Von Neumann said each number n is the set of numbers less than n, so 3 is {null,{null},{null,{null}}}, and 1 is a member of 3.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.2)
     A reaction: See Idea 645 - Zermelo could save Plato from the criticisms of Aristotle! These two accounts are cited by opponents of the set-theoretical account of numbers, because it seems impossible to arbitrate between them.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Numbers do not exist independently; the essence of a number is its relations to other numbers [Shapiro]
     Full Idea: The structuralist vigorously rejects any sort of ontological independence among the natural numbers; the essence of a natural number is its relations to other natural numbers.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.1)
     A reaction: This seems to place the emphasis on ordinals (what order?) rather than on cardinality (how many?). I am strongly inclined to think that this is the correct view, though you can't really have relations if there is nothing to relate.
A 'system' is related objects; a 'pattern' or 'structure' abstracts the pure relations from them [Shapiro]
     Full Idea: A 'system' is a collection of objects with certain relations among them; a 'pattern' or 'structure' is the abstract form of a system, highlighting the interrelationships and ignoring any features they do not affect how they relate to other objects.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 10.1)
     A reaction: Note that 'ignoring' features is a psychological account of abstraction, which (thanks to Frege and Geach) is supposed to be taboo - but which I suspect is actually indispensable in any proper account of thought and concepts.
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Logicism seems to be a non-starter if (as is widely held) logic has no ontology of its own [Shapiro]
     Full Idea: The thesis that principles of arithmetic are derivable from the laws of logic runs against a now common view that logic itself has no ontology. There are no particular logical objects. From this perspective logicism is a non-starter.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 5.1)
     A reaction: This criticism strikes me as utterly devastating. There are two routes to go: prove that logic does have an ontology of objects (what would they be?), or - better - deny that arithmetic contains any 'objects'. Or give up logicism.
6. Mathematics / C. Sources of Mathematics / 7. Formalism
Term Formalism says mathematics is just about symbols - but real numbers have no names [Shapiro]
     Full Idea: Term Formalism is the view that mathematics is just about characters or symbols - the systems of numerals and other linguistic forms. ...This will cover integers and rational numbers, but what are real numbers supposed to be, if they lack names?
     From: Stewart Shapiro (Thinking About Mathematics [2000], 6.1.1)
     A reaction: Real numbers (such as pi and root-2) have infinite decimal expansions, so we can start naming those. We could also start giving names like 'Harry' to other reals, though it might take a while. OK, I give up.
Game Formalism is just a matter of rules, like chess - but then why is it useful in science? [Shapiro]
     Full Idea: Game Formalism likens mathematics to chess, where the 'content' of mathematics is exhausted by the rules of operating with its language. ...This, however, leaves the problem of why the mathematical games are so useful to the sciences.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 6.1.2)
     A reaction: This thought pushes us towards structuralism. It could still be a game, but one we learned from observing nature, which plays its own games. Chess is, after all, modelled on warfare.
Deductivism says mathematics is logical consequences of uninterpreted axioms [Shapiro]
     Full Idea: The Deductivist version of formalism (sometimes called 'if-thenism') says that the practice of mathematics consists of determining logical consequences of otherwise uninterpreted axioms.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 6.2)
     A reaction: [Hilbert is the source] More plausible than Term or Game Formalism (qv). It still leaves the question of why it seems applicable to nature, and why those particular axioms might be chosen. In some sense, though, it is obviously right.
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / b. Intuitionism
Critics resent the way intuitionism cripples mathematics, but it allows new important distinctions [Shapiro]
     Full Idea: Critics commonly complain that the intuitionist restrictions cripple the mathematician. On the other hand, intuitionist mathematics allows for many potentially important distinctions not available in classical mathematics, and is often more subtle.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 7.1)
     A reaction: The main way in which it cripples is its restriction on talk of infinity ('Cantor's heaven'), which was resented by Hilbert. Since high-level infinities are interesting, it would be odd if we were not allowed to discuss them.
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / c. Conceptualism
Conceptualist are just realists or idealist or nominalists, depending on their view of concepts [Shapiro]
     Full Idea: I classify conceptualists according to what they say about properties or concepts. If someone classified properties as existing independent of language I would classify her as a realist in ontology of mathematics. Or they may be idealists or nominalists.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 2.2.1)
     A reaction: In other words, Shapiro wants to eliminate 'conceptualist' as a useful label in philosophy of mathematics. He's probably right. All thought involves concepts, but that doesn't produce a conceptualist theory of, say, football.
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
'Impredicative' definitions refer to the thing being described [Shapiro]
     Full Idea: A definition of a mathematical entity is 'impredicative' if it refers to a collection that contains the defined entity. The definition of 'least upper bound' is impredicative as it refers to upper bounds and characterizes a member of this set.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 1.2)
     A reaction: The big question is whether mathematics can live with impredicative definitions, or whether they threaten to be viciously circular, and undermine the whole enterprise.
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Rationalism tries to apply mathematical methodology to all of knowledge [Shapiro]
     Full Idea: Rationalism is a long-standing school that can be characterized as an attempt to extend the perceived methodology of mathematics to all of knowledge.
     From: Stewart Shapiro (Thinking About Mathematics [2000], 1.1)
     A reaction: Sometimes called 'Descartes's Dream', or the 'Enlightenment Project', the dream of proving everything. Within maths, Hilbert's Programme aimed for the same certainty. Idea 22 is the motto for the opposition to this approach.
16. Persons / F. Free Will / 5. Against Free Will
Saying we must will whatever we decide to will leads to an infinite regress [Leibniz]
     Full Idea: As for volition itself, to say that it is the object of free will is incorrect. We will to act, strictly speaking, and we do not will to will, else we should still say we will to have the will to will, and that would go on to infinity.
     From: Gottfried Leibniz (The Theodicy [1710], p.151), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 4.IV
     A reaction: This strikes me as an elementary difficulty which most fans of free will appear to evade. Thoughts just arise in us, and some of them are volitions. We can say there is then a 'gap' (Searle) where we choose, but what happens in the gap?
17. Mind and Body / A. Mind-Body Dualism / 5. Parallelism
Perfections of soul subordinate the body, but imperfections of soul submit to the body [Leibniz]
     Full Idea: Insofar as the soul has perfection ...God has accommodated the body to the soul, and has arranged beforehand that the body is impelled to execute its orders. Insofar as it is imperfect and confused, God accommodates soul to body, swayed by passions.
     From: Gottfried Leibniz (The Theodicy [1710], p.159), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 3.IV
     A reaction: Perkins says this is the nearest Leibniz gets to the idea of interaction between body and soul. Perfection and confusion are on a continuum for Leibniz. With such speculations I always wonder how these things can be known. How perfect is my mind?
20. Action / B. Preliminaries of Action / 2. Willed Action / a. Will to Act
Will is an inclination to pursue something good [Leibniz]
     Full Idea: One may say that 'will' consists in the inclination to do something in proportion to the good it contains.
     From: Gottfried Leibniz (The Theodicy [1710], p.136), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.III
     A reaction: This emphasises that the will is faced with options, rather than generating the options. The context is a discussion of the nature of God's will. I think 'will' is a really useful concept, and dislike the Hobbesian rejection of will.
22. Metaethics / B. Value / 2. Values / e. Death
Most people facing death would happily re-live a similar life, with just a bit of variety [Leibniz]
     Full Idea: I believe there would be few persons who, being at the point of death, were not content to take up life again, on condition of passing through the same amount of good and evil, provided that it were not the same kind.
     From: Gottfried Leibniz (The Theodicy [1710], p.130), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.IV
     A reaction: Nice challenge. People who refuse the offer are not necessarily suicidal. He's probably right, but Leibniz doesn't recognise the factor of boredom. Look up the suicide note of the actor George Sanders! One life may be enough.
22. Metaethics / B. Value / 2. Values / j. Evil
Metaphysical evil is imperfection; physical evil is suffering; moral evil is sin [Leibniz]
     Full Idea: Evil may be taken metaphysically, physically, and morally. Metaphysical evil consists in mere imperfection, physical evil is suffering, and moral evil is sin.
     From: Gottfried Leibniz (The Theodicy [1710], p.136), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.IV
     A reaction: There seem to be plenty of imperfections in the world which don't look like evil. Or do you only declare it to be an imperfection because it seems to be evil (by some other standard)? Human evil comes from ignorance, so metaphysical explains moral.
22. Metaethics / C. The Good / 1. Goodness / d. Good as virtue
Basing ethics on flourishing makes it consequentialist, as actions are judged by contributing to it [Harman]
     Full Idea: Basing ethics on human flourishing tends towards utilitarianism or consequentialism; actions, character traits, laws, and so on are to be assessed with reference to their contributions to human flourishing.
     From: Gilbert Harman (Human Flourishing, Ethics and Liberty [1983], 9.2.2)
     A reaction: This raises the question of whether only virtue can contribute to flourishing, or whether a bit of vice might be helpful. This problem presumably pushed the Stoics to say that virtue itself is the good, rather than the resulting flourishing.
22. Metaethics / C. The Good / 1. Goodness / g. Consequentialism
You can't assess moral actions without referring to the qualities of character that produce them [Leibniz]
     Full Idea: One is more worthy of praise when one owes the action to one's good qualities, and more culpable in proportion as one has been impelled by one's evil qualities; assessing actions without weighing the qualities whence they spring is to talk at random.
     From: Gottfried Leibniz (The Theodicy [1710], p.426), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 4.IV
     A reaction: Mill tries to separate judgement of the agent from judgement of the consequences of the action, but I think Leibniz has spotted that just judging outcomes ceases to be a 'moral' judgement.
22. Metaethics / C. The Good / 2. Happiness / b. Eudaimonia
What counts as 'flourishing' must be relative to various sets of values [Harman]
     Full Idea: If we base our ethics on human flourishing, one implication would seem to be moral relativism, since what counts as 'flourishing' seems inevitably relative to one or other set of values.
     From: Gilbert Harman (Human Flourishing, Ethics and Liberty [1983], 9.2.1)
     A reaction: This remark seems to make the relativist assumption that all value systems are equal. For Aristotle, flourishing is no more relative than health is. No one can assert that illness has an intrinsically high value in human life.
28. God / A. Divine Nature / 2. Divine Nature
God must be intelligible, to select the actual world from the possibilities [Leibniz]
     Full Idea: The cause of the world must be intelligent: for this existing world being contingent and an infinity of worlds being equally possible, with equal claim to existence, the cause of the world must have regarded all of these worlds to fix on one of them.
     From: Gottfried Leibniz (The Theodicy [1710], p.127), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.II
     A reaction: A wonderfully Leibnizian way of putting what looks like the design argument.
28. God / A. Divine Nature / 3. Divine Perfections
The intelligent cause must be unique and all-perfect, to handle all the interconnected possibilities [Leibniz]
     Full Idea: The intelligent cause ought to be infinite in all ways, and absolutely perfect in power, in wisdom, and in goodness, since it relates to all that which is possible. Also, since all is connected together, there is no ground for admitting more than one.
     From: Gottfried Leibniz (The Theodicy [1710], p.128), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.II
     A reaction: Notice that Leibniz's possible worlds seem to be all connected together, unlike David Lewis's worlds, which are discrete. Personally I suspect that all perfections will lead to contradiction, though Leibniz strongly argues against it.
28. God / A. Divine Nature / 6. Divine Morality / a. Divine morality
God prefers men to lions, but might not exterminate lions to save one man [Leibniz]
     Full Idea: It is certain that God sets greater store by a man than a lion; nevertheless it can hardly be said with certainty that God prefers a single man in all respects to the whole of lion-kind.
     From: Gottfried Leibniz (The Theodicy [1710], p.189), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.IV
     A reaction: Lovely problems arise when you guess at God's values! We have the same problem. Would you kill a poacher who was wiping out the last remaining lions? How many lions would you kill to save a human?
28. God / A. Divine Nature / 6. Divine Morality / b. Euthyphro question
If justice is arbitrary, or fixed but not observed, or not human justice, this undermines God [Leibniz]
     Full Idea: The three dogmas (1) that the nature of justice is arbitrary, (2) it is fixed, but not certain God will observe it, or (3) the justice we know is not that which God observes, destroy our confidence in the love of God.
     From: Gottfried Leibniz (The Theodicy [1710], p.237), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.III
     A reaction: Leibniz proceeds to carefully refute these three responses to the dilemma about how justice relates to God.
28. God / B. Proving God / 2. Proofs of Reason / a. Ontological Proof
God is the first reason of things; our experiences are contingent, and contain no necessity [Leibniz]
     Full Idea: God is the first reason of things: all that we see and experience is contingent and nothing in them renders their existence necessary.
     From: Gottfried Leibniz (The Theodicy [1710], p.127), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.II
     A reaction: Perkins presents this as the first step in one of Leibniz's arguments for God. They all seem to be variants of the ontological argument. [His 'Theodicy' is the Huggard translation, 1985] This resembles Aquinas's Third Way.
28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
The laws of physics are wonderful evidence of an intelligent and free being [Leibniz]
     Full Idea: These admirable laws [of physics] are wonderful evidence of an intelligent and free being, as opposed to the system of absolute and brute necessity, advocated by Strato and Spinoza.
     From: Gottfried Leibniz (The Theodicy [1710], p.332), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.II
     A reaction: Note the swipe at Spinoza. Leibniz defends the absolute necessities residing in God, but is too polite to call those 'brute', though personally I can't see the difference. But he says the laws arise from 'perfection and order', not from God's necessity.
29. Religion / D. Religious Issues / 1. Religious Commitment / a. Religious Belief
Prayers are useful, because God foresaw them in his great plan [Leibniz]
     Full Idea: Not only cares and labours but also prayers are useful; God having had these prayers in view before he regulated things.
     From: Gottfried Leibniz (The Theodicy [1710], Abridge III)
     A reaction: Hm. I'm struggling with this one. So I can't skip prayers today, because God has foreseen them and included them in his great plan? Hard to motivate yourself, like starting a game of chess after you've already been declared the winner.
29. Religion / D. Religious Issues / 3. Problem of Evil / a. Problem of Evil
How can an all-good, wise and powerful being allow evil, sin and apparent injustice? [Leibniz]
     Full Idea: There is this question of natural theology, how a sole Principle, all-good, all-wise and all-powerful, has been able to admit evil, and especially to permit sin, and how it could resolve to make the wicked often happy and the good unhappy?
     From: Gottfried Leibniz (The Theodicy [1710], p.098), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.IV
     A reaction: His answer is, roughly, that there is an unavoidable trade-off, which humans cannot fully understand. Personally I would say that if there is a God, the evidence for his benevolence towards humanity is not encouraging.
Being confident of God's goodness, we disregard the apparent local evils in the visible world [Leibniz]
     Full Idea: Being made confident by demonstrations of the goodness and the justice of God, we disregard the appearances of harshness and justice which we see in this small portion of his Kingdom that is exposed to our gaze.
     From: Gottfried Leibniz (The Theodicy [1710], p.120), quoted by Franklin Perkins - Leibniz: Guide for the Perplexed 2.IV
     A reaction: Hm. If this locality is full of evils, and the rest of it is much better, how come we are stuck in this miserable corner of things? God is obliged to compromise, but did he select us to get the worst of it?