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All the ideas for 'Thinking About Mathematics', 'fragments/reports' and 'After Finitude'

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41 ideas

1. Philosophy / B. History of Ideas / 5. Later European Thought
Since Kant we think we can only access 'correlations' between thinking and being [Meillassoux]
     Full Idea: The central notion of philosophy since Kant is 'correlation' - that we only ever have access to the correlation between thinking and being, and never to either term considered apart from the other.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 1)
     A reaction: Meillassoux's charge is that philosophy has thereby completely failed to grasp the scientific revolution, which has used mathematics to make objectivity possible. Quine and Putnam would be good examples of what he has in mind.
The Copernican Revolution decentres the Earth, but also decentres thinking from reality [Meillassoux]
     Full Idea: The Copernican Revolution is not so much the decentring of observers in the solar system, but (by the mathematizing of nature) the decentring of thought relative to the world within the process of knowledge.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 5)
     A reaction: In other words, I take it, the Copernican Revolution was the discovery of objectivity. That is a very nice addition to my History of Ideas collection.
1. Philosophy / B. History of Ideas / 6. Twentieth Century Thought
In Kant the thing-in-itself is unknowable, but for us it has become unthinkable [Meillassoux]
     Full Idea: The major shift that has occurred in the conception of thought from Kant's time to ours is from the unknowability of the thing-in-itself to its unthinkability.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 2)
     A reaction: Meillassoux is making the case that philosophy is alienating us more and more from the triumphant realism of the scientific revolution. He says thinking has split from being. He's right. Modern American pragmatists are the worst (not Peirce!).
1. Philosophy / G. Scientific Philosophy / 3. Scientism
Since Kant, philosophers have claimed to understand science better than scientists do [Meillassoux]
     Full Idea: Ever since Kant, to think science as a philosopher has been to claim that science harbours a meaning other than the one delivered by science itself.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 5)
     A reaction: The point is that science discovered objectivity (via the mathematising of nature), and Kant utterly rejected objectivity, by enmeshing the human mind in every possible scientific claim. This makes Meillassoux and I very cross.
2. Reason / A. Nature of Reason / 5. Objectivity
Since Kant, objectivity is defined not by the object, but by the statement's potential universality [Meillassoux]
     Full Idea: Since Kant, objectivity is no longer defined with reference to the object in itself, but rather with reference to the possible universality of an objective statement.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 1)
     A reaction: Meillassoux disapproves of this, as a betrayal by philosophers of the scientific revolution, which gave us true objectivity (e.g. about how the world was before humanity).
2. Reason / B. Laws of Thought / 2. Sufficient Reason
If we insist on Sufficient Reason the world will always be a mystery to us [Meillassoux]
     Full Idea: So long as we continue to believe that there is a reason why things are the way they are rather than some other way, we will construe this world is a mystery, since no such reason will every be vouchsafed to us.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 4)
     A reaction: Giving up sufficient reason sounds like a rather drastic response to this. Put it like this: Will we ever be able to explain absolutely everything? No. So will the world always be a little mysterious to us? Yes, obviously. Is that a problem? No!
2. Reason / B. Laws of Thought / 3. Non-Contradiction
Non-contradiction is unjustified, so it only reveals a fact about thinking, not about reality? [Meillassoux]
     Full Idea: The principle of non-contradiction itself is without reason, and consequently it can only be the norm for what is thinkable by us, rather than for what is possible in the absolute sense.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 2)
     A reaction: This is not Meillassoux's view, but describes the modern heresy of 'correlationism', which ties all assessments of how reality is to our capacity to think about it. Personally I take logical non-contradiction to derive from non-contradiction in nature.
4. Formal Logic / E. Nonclassical Logics / 7. Paraconsistency
We can allow contradictions in thought, but not inconsistency [Meillassoux]
     Full Idea: For contemporary logicians, it is not non-contradiction that provides the criterion for what is thinkable, but rather inconsistency.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 3)
     A reaction: The point is that para-consistent logic might permit isolated contradictions (as true) within a system, but it is only contradiction across the system (inconsistencies) which make the system untenable.
Paraconsistent logics are to prevent computers crashing when data conflicts [Meillassoux]
     Full Idea: Paraconsistent logics were only developed in order to prevent computers, such as expert medical systems, from deducing anything whatsoever from contradictory data, because of the principle of 'ex falso quodlibet'.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 3)
Paraconsistent logic is about statements, not about contradictions in reality [Meillassoux]
     Full Idea: Paraconsistent logics are only ever dealing with contradictions inherent in statements about the world, never with the real contradictions in the world.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 3)
     A reaction: Thank goodness for that! I can accept that someone in a doorway is both in the room and not in the room, but not that they are existing in a real state of contradiction. I fear that a few daft people embrace the logic as confirming contradictory reality.
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 / A. Nature of Mathematics / 4. Using Numbers / g. Applying mathematics
What is mathematically conceivable is absolutely possible [Meillassoux]
     Full Idea: We must establish the thesis that what is mathematically conceivable is absolutely possible.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 5)
     A reaction: The truth of this thesis would permanently establish mathematics as the only possible language of science. Personally I have no idea how you could prove or assess such a thesis. It is a lovely speculation, though. 'The structure of the possible' (p,127)
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.
7. Existence / A. Nature of Existence / 1. Nature of Existence
The absolute is the impossibility of there being a necessary existent [Meillassoux]
     Full Idea: We maintain that it is absolutely necessary that every entity might not exist. ...The absolute is the absolute impossibility of a necessary being.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 3)
     A reaction: This is the main thesis of his book. The usual candidates for necessary existence are God, and mathematical objects. I am inclined to agree with Meillassoux.
7. Existence / A. Nature of Existence / 5. Reason for Existence
It is necessarily contingent that there is one thing rather than another - so something must exist [Meillassoux]
     Full Idea: It is necessary that there be something rather than nothing because it is necessarily contingent that there is something rather than something else.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 3)
     A reaction: The great charm of metaphysics is the array of serious answers to the question of why there is something rather than nothing. You'll need to read Meillassoux's book to understand this one.
7. Existence / A. Nature of Existence / 6. Criterion for Existence
We must give up the modern criterion of existence, which is a correlation between thought and being [Meillassoux]
     Full Idea: It is incumbent upon us to break with the ontological requisite of the moderns, according to which 'to be is to be a correlate'.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 2)
     A reaction: He blames Kant for this pernicious idea, which has driven philosophy away from realist science, when it should be supporting and joining it. As a realist I agree, and find Meillassoux very illuminating on the subject.
10. Modality / B. Possibility / 5. Contingency
Possible non-being which must be realised is 'precariousness'; absolute contingency might never not-be [Meillassoux]
     Full Idea: My term 'precariousness' designates a possibility of not-being which must eventually be realised. By contrast, absolute contingency designates a pure possibility; one which may never be realised.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 3)
     A reaction: I thoroughly approve of this distinction, because I have often enountered the assumption that all contingency is precariousness, and I have never seen why that should be so. In Aquinas's Third Way, for example. The 6 on a die may never come up.
10. Modality / B. Possibility / 7. Chance
The idea of chance relies on unalterable physical laws [Meillassoux]
     Full Idea: The very notion of chance is only conceivable on condition that there are unalterable physical laws.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 4)
     A reaction: Laws might be contingent, even though they never alter. Chance in horse racing relies on the stability of whole institution of horse racing.
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / b. Transcendental idealism
Unlike speculative idealism, transcendental idealism assumes the mind is embodied [Meillassoux]
     Full Idea: What distinguishes transcendental idealism from speculative idealism is the fact that the former does not posit the existence of the transcendental subject apart from its bodily individuation.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 1)
     A reaction: These modern French philosophers explain things so much more clearly than the English! The 'speculative' version is seen in Berkeley. On p.17 he says transcendental idealism is 'civilised', and speculative idealism is 'uncouth'.
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / c. Primary qualities
The aspects of objects that can be mathematical allow it to have objective properties [Meillassoux]
     Full Idea: All aspects of the object that can give rise to a mathematical thought rather than to a perception or a sensation can be meaningfully turned into the properties of the thing not only as it is with me, but also as it is without me.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 1)
     A reaction: This is Meillassoux's spin on the primary/secondary distinction, which he places at the heart of the scientific revolution. Cartesian dualism offers a separate space for the secondary qualities. He is appalled when philosophers reject the distinction.
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.
14. Science / B. Scientific Theories / 1. Scientific Theory
How can we mathematically describe a world that lacks humans? [Meillassoux]
     Full Idea: How is mathematical discourse able to describe a reality where humanity is absent?
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 1)
     A reaction: He is referring to the prehistoric world. He takes this to be a key question about the laws of nature. We extrapolate mathematically from the experienced world, relying on the stability of the laws. Must they be necessary to be stable? No, it seems.
14. Science / C. Induction / 3. Limits of Induction
Hume's question is whether experimental science will still be valid tomorrow [Meillassoux]
     Full Idea: Hume's question can be formulated as follows: can we demonstrate that the experimental science which is possible today will still be possible tomorrow?
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 4)
     A reaction: Could there be deep universal changes going on in nature which science could never, even in principle, detect?
15. Nature of Minds / A. Nature of Mind / 2. Psuche
Xenocrates held that the soul had no form or substance, but was number [Xenocrates, by Cicero]
     Full Idea: Xenocrates denied that the soul had form or any substance, but said that it was number, and the power of number, as had been held by Pythagoras long before, was the highest in nature.
     From: report of Xenocrates (fragments/reports [c.327 BCE]) by M. Tullius Cicero - Tusculan Disputations I.x.20
     A reaction: This shows how strong the Pythagorean influence was in the Academy. This is not totally stupid. Dawkins holds that the essence of DNA is information, which can be expressed mathematically. Xenocrates was a functionalist.
16. Persons / B. Nature of the Self / 4. Presupposition of Self
The transcendental subject is not an entity, but a set of conditions making science possible [Meillassoux]
     Full Idea: The transcendental subject simply cannot be said to exist; which is to say that the subject is not an entity, but rather a set of conditions rendering objective scientific knowledge of entities possible.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 1)
     A reaction: Meillassoux treats this as part of the Kantian Disaster, which made an accurate account of the scientific revolution impossible for philosophers. Kant's ego seems to have primarily an epistemological role.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / b. Scientific necessity
If the laws of nature are contingent, shouldn't we already have noticed it? [Meillassoux]
     Full Idea: The standard objection is that if the laws of nature were actually contingent, we would already have noticed it.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 4)
     A reaction: Meillassoux offers a sustained argument that the laws of nature are necessarily contingent. In Idea 19660 he distinguishes contingencies that must change from those that merely could change.
Why are contingent laws of nature stable? [Meillassoux]
     Full Idea: We must ask how we are to explain the manifest stability of physical laws, given that we take these to be contingent?
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 4)
     A reaction: Meissalloux offers a very deep and subtle answer to this question... It is based on the possibilities of chaos being an uncountable infinity... It is a very nice question, which physicists might be able to answer, without help from philosophy.
28. God / B. Proving God / 2. Proofs of Reason / a. Ontological Proof
The ontological proof of a necessary God ensures a reality external to the mind [Meillassoux]
     Full Idea: Since Descartes conceives of God as existing necessarily, whether I exist to think of him or not, Descartes assures me of a possible access to an absolute reality - a Great Outdoors that is not a correlate of my thought.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 2)
     A reaction: His point is that the ontological argument should be seen as part of the scientific revolution, and not an anomaly within it. Interesting.
28. God / C. Attitudes to God / 5. Atheism
Now that the absolute is unthinkable, even atheism is just another religious belief (though nihilist) [Meillassoux]
     Full Idea: Once the absolute has become unthinkable, even atheism, which also targets God's inexistence in the manner of an absolute, is reduced to a mere belief, and hence to a religion, albeit of the nihilist kind.
     From: Quentin Meillassoux (After Finitude; the necessity of contingency [2006], 2)
     A reaction: An interesting claim. Rather hard to agree or disagree, though the idea that atheism must qualify as a religion seems odd. If it is unqualified it does have the grand quality of a religion, but if it is fallibilist it just seems like an attitude.