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106 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
Wisdom for one instant is as good as wisdom for eternity [Chrysippus]
     Full Idea: If a person has wisdom for one instant, he is no less happy than he who possesses it for eternity.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by Pierre Hadot - Philosophy as a way of life 8
     A reaction: [Hadot quotes Plutarch 'On Common Conceptions' 8,1062a] This makes it sound awfully like some sort of Buddhist 'enlightenment', which strikes like lightning. He does wisdom recognise itself - by a warm glow, or by the cautious thought that got you there?
1. Philosophy / A. Wisdom / 2. Wise People
Wise men should try to participate in politics, since they are a good influence [Chrysippus, by Diog. Laertius]
     Full Idea: The wise man will participate in politics unless something prevents him, for he will restrain vice and promote virtue.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.121
     A reaction: [from lost On Ways of Life Bk 1] We have made modern politics so hostile for its participants, thanks to cruel media pressure, that the best people now run a mile from it. Disastrous.
1. Philosophy / D. Nature of Philosophy / 4. Divisions of Philosophy
Three branches of philosophy: first logic, second ethics, third physics (which ends with theology) [Chrysippus]
     Full Idea: There are three kinds of philosophical theorems, logical, ethical, and physical; of these the logic should be placed first, ethics second, and physics third (and theology is the final topic in physics).
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by Plutarch - 70: Stoic Self-contradictions 1035a
     A reaction: [in his lost 'On Lives' Bk 4] 'Theology is the final topic in physics'! That should create a stir in theology departments. Is this an order of study, or of importance? You come to theology right at the end of your studies.
2. Reason / B. Laws of Thought / 2. Sufficient Reason
Chrysippus said the uncaused is non-existent [Chrysippus, by Plutarch]
     Full Idea: Chrysippus said that the uncaused is altogether non-existent.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Plutarch - 70: Stoic Self-contradictions 1045c
     A reaction: The difficulty is to see what empirical basis there can be for such a claim, or what argument of any kind other than an intuition. Induction is the obvious answer, but Hume teaches us scepticism about any claim that 'there can be no exceptions'.
3. Truth / B. Truthmakers / 10. Making Future Truths
The causes of future true events must exist now, so they will happen because of destiny [Chrysippus, by Cicero]
     Full Idea: True future events cannot be such as do not possess causes on account of which they will happen; therefore that which is true must possess causes: and so, when the [true future events] happen they will have happened as a result of destiny.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by M. Tullius Cicero - On Fate ('De fato') 9.23-8
     A reaction: [exact ref unclear] Presumably the current causes are the truthmakers for the future events, and so the past is the truthmaker of the future, if you are a determinist.
3. Truth / C. Correspondence Truth / 2. Correspondence to Facts
Graspable presentations are criteria of facts, and are molded according to their objects [Chrysippus, by Diog. Laertius]
     Full Idea: Of presentations, some are graspable, some non-graspable. The graspable presentation, which they say is the criterion of facts [pragmata], is that which comes from an existing object and is stamped and molded in accordance wth the existing object itself.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.46
     A reaction: [in lost Physics Bk 2] The big modern anguish over truth-as-correspondence is how you are supposed to verify the 'accordance'. This idea seems to blur the ideas of truth and justification (the 'criterion'), and you can't have both as accordance.
3. Truth / C. Correspondence Truth / 3. Correspondence Truth critique
How could you ever know that the presentation is similar to the object? [Sext.Empiricus on Chrysippus]
     Full Idea: One cannot say that the soul grasps the externally existing objects by means of the states of the senses on the basis of the similarity of these states to the externally existing objects. For on what basis will it know the similarity?
     From: comment on Chrysippus (fragments/reports [c.240 BCE]) by Sextus Empiricus - Outlines of Pyrrhonism 2.74
     A reaction: This exactly the main modern reason for rejecting the correspondence theory of truth. You are welcome to affirm a robust view of truth, but supporting it by claiming a correspondence or resemblance is dubious.
4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Stoic propositional logic is like chemistry - how atoms make molecules, not the innards of atoms [Chrysippus, by Devlin]
     Full Idea: In Stoic logic propositions are treated the way atoms are treated in present-day chemistry, where the focus is on the way atoms fit together to form molecules, rather than on the internal structure of the atoms.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Keith Devlin - Goodbye Descartes Ch.2
     A reaction: A nice analogy to explain the nature of Propositional Logic, which was invented by the Stoics (N.B. after Aristotle had invented predicate logic).
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
Chrysippus has five obvious 'indemonstrables' of reasoning [Chrysippus, by Diog. Laertius]
     Full Idea: Chrysippus has five indemonstrables that do not need demonstration:1) If 1st the 2nd, but 1st, so 2nd; 2) If 1st the 2nd, but not 2nd, so not 1st; 3) Not 1st and 2nd, the 1st, so not 2nd; 4) 1st or 2nd, the 1st, so not 2nd; 5) 1st or 2nd, not 2nd, so 1st.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.80-81
     A reaction: [from his lost text 'Dialectics'; squashed to fit into one quote] 1) is Modus Ponens, 2) is Modus Tollens. 4) and 5) are Disjunctive Syllogisms. 3) seems a bit complex to be an indemonstrable.
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Trying to represent curves, we study arbitrary functions, leading to the ordinals, which produces set theory [Cantor, by Lavine]
     Full Idea: The notion of a function evolved gradually from wanting to see what curves can be represented as trigonometric series. The study of arbitrary functions led Cantor to the ordinal numbers, which led to set theory.
     From: report of George Cantor (works [1880]) by Shaughan Lavine - Understanding the Infinite I
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / c. Basic theorems of ST
Cantor's Theorem: for any set x, its power set P(x) has more members than x [Cantor, by Hart,WD]
     Full Idea: Cantor's Theorem says that for any set x, its power set P(x) has more members than x.
     From: report of George Cantor (works [1880]) by William D. Hart - The Evolution of Logic 1
Cantor proved that all sets have more subsets than they have members [Cantor, by Bostock]
     Full Idea: Cantor's diagonalisation argument generalises to show that any set has more subsets than it has members.
     From: report of George Cantor (works [1880]) by David Bostock - Philosophy of Mathematics 4.5
     A reaction: Thus three members will generate seven subsets. This means that 'there is no end to the series of cardinal numbers' (Bostock p.106).
4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Sets
If a set is 'a many thought of as one', beginners should protest against singleton sets [Cantor, by Lewis]
     Full Idea: Cantor taught that a set is 'a many, which can be thought of as one'. ...After a time the unfortunate beginner student is told that some classes - the singletons - have only a single member. Here is a just cause for student protest, if ever there was one.
     From: report of George Cantor (works [1880]) by David Lewis - Parts of Classes 2.1
     A reaction: There is a parallel question, almost lost in the mists of time, of whether 'one' is a number. 'Zero' is obviously dubious, but if numbers are for counting, that needs units, so the unit is the precondition of counting, not part of it.
4. Formal Logic / F. Set Theory ST / 3. Types of Set / d. Infinite Sets
Cantor showed that supposed contradictions in infinity were just a lack of clarity [Cantor, by Potter]
     Full Idea: Cantor's theories exhibited the contradictions others had claimed to derive from the supposition of infinite sets as confusions resulting from the failure to mark the necessary distinctions with sufficient clarity.
     From: report of George Cantor (works [1880]) by Michael Potter - Set Theory and Its Philosophy Intro 1
The continuum is the powerset of the integers, which moves up a level [Cantor, by Clegg]
     Full Idea: Cantor discovered that the continuum is the powerset of the integers. While adding or multiplying infinities didn't move up a level of complexity, multiplying a number by itself an infinite number of times did.
     From: report of George Cantor (works [1880]) by Brian Clegg - Infinity: Quest to Think the Unthinkable Ch.14
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / d. Axiom of Unions III
The Axiom of Union dates from 1899, and seems fairly obvious [Cantor, by Maddy]
     Full Idea: Cantor first stated the Union Axiom in a letter to Dedekind in 1899. It is nearly too obvious to deserve comment from most commentators. Justifications usually rest on 'limitation of size' or on the 'iterative conception'.
     From: report of George Cantor (works [1880]) by Penelope Maddy - Believing the Axioms I §1.3
     A reaction: Surely someone can think of some way to challenge it! An opportunity to become notorious, and get invited to conferences.
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / b. Combinatorial sets
Cantor's sets were just collections, but Dedekind's were containers [Cantor, by Oliver/Smiley]
     Full Idea: Cantor's definition of a set was a collection of its members into a whole, but within a few years Dedekind had the idea of a set as a container, enclosing its members like a sack.
     From: report of George Cantor (works [1880]) by Oliver,A/Smiley,T - What are Sets and What are they For? Intro
     A reaction: As the article goes on to show, these two view don't seem significantly different until you start to ask about the status of the null set and of singletons. I intuitively vote for Dedekind. Set theory is the study of brackets.
5. Theory of Logic / B. Logical Consequence / 5. Modus Ponens
Modus ponens is one of five inference rules identified by the Stoics [Chrysippus, by Devlin]
     Full Idea: Modus ponens is just one of the five different inference rules identified by the Stoics.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Keith Devlin - Goodbye Descartes Ch.2
     A reaction: Modus ponens strikes me as being more like a definition of implication than a 'rule'. Implication is what gets you from one truth to another. All the implications of a truth must also be true.
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
Every proposition is either true or false [Chrysippus, by Cicero]
     Full Idea: We hold fast to the position, defended by Chrysippus, that every proposition is either true or false.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by M. Tullius Cicero - On Fate ('De fato') 38
     A reaction: I am intrigued to know exactly how you defend this claim. It may depend what you mean by a proposition. A badly expressed proposition may have indeterminate truth, quite apart from the vague, the undecidable etc.
5. Theory of Logic / K. Features of Logics / 8. Enumerability
There are infinite sets that are not enumerable [Cantor, by Smith,P]
     Full Idea: Cantor's Theorem (1874) says there are infinite sets that are not enumerable. This is proved by his 1891 'diagonal argument'.
     From: report of George Cantor (works [1880]) by Peter Smith - Intro to Gödel's Theorems 2.3
     A reaction: [Smith summarises the diagonal argument]
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / b. Cantor's paradox
Cantor's Paradox: the power set of the universe must be bigger than the universe, yet a subset of it [Cantor, by Hart,WD]
     Full Idea: The problem of Cantor's Paradox is that the power set of the universe has to be both bigger than the universe (by Cantor's theorem) and not bigger (since it is a subset of the universe).
     From: report of George Cantor (works [1880]) by William D. Hart - The Evolution of Logic 3
     A reaction: Russell eliminates the 'universe' in his theory of types. I don't see why you can't just say that the members of the set are hypothetical rather than real, and that hypothetically the universe might contain more things than it does.
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / e. Mirimanoff's paradox
The powerset of all the cardinal numbers is required to be greater than itself [Cantor, by Friend]
     Full Idea: Cantor's Paradox says that the powerset of a set has a cardinal number strictly greater than the original set, but that means that the powerset of the set of all the cardinal numbers is greater than itself.
     From: report of George Cantor (works [1880]) by Michèle Friend - Introducing the Philosophy of Mathematics
     A reaction: Friend cites this with the Burali-Forti paradox and the Russell paradox as the best examples of the problems of set theory in the early twentieth century. Did this mean that sets misdescribe reality, or that we had constructed them wrongly?
6. Mathematics / A. Nature of Mathematics / 1. Mathematics
Cantor named the third realm between the finite and the Absolute the 'transfinite' [Cantor, by Lavine]
     Full Idea: Cantor believed he had discovered that between the finite and the 'Absolute', which is 'incomprehensible to the human understanding', there is a third category, which he called 'the transfinite'.
     From: report of George Cantor (works [1880]) by Shaughan Lavine - Understanding the Infinite III.4
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
Cantor proved the points on a plane are in one-to-one correspondence to the points on a line [Cantor, by Lavine]
     Full Idea: In 1878 Cantor published the unexpected result that one can put the points on a plane, or indeed any n-dimensional space, into one-to-one correspondence with the points on a line.
     From: report of George Cantor (works [1880]) by Shaughan Lavine - Understanding the Infinite III.1
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
Cantor took the ordinal numbers to be primary [Cantor, by Tait]
     Full Idea: Cantor took the ordinal numbers to be primary: in his generalization of the cardinals and ordinals into the transfinite, it is the ordinals that he calls 'numbers'.
     From: report of George Cantor (works [1880]) by William W. Tait - Frege versus Cantor and Dedekind VI
     A reaction: [Tait says Dedekind also favours the ordinals] It is unclear how the matter might be settled. Humans cannot give the cardinality of large groups without counting up through the ordinals. A cardinal gets its meaning from its place in the ordinals?
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / d. Natural numbers
Cantor presented the totality of natural numbers as finite, not infinite [Cantor, by Mayberry]
     Full Idea: Cantor taught us to regard the totality of natural numbers, which was formerly thought to be infinite, as really finite after all.
     From: report of George Cantor (works [1880]) by John Mayberry - What Required for Foundation for Maths? p.414-2
     A reaction: I presume this is because they are (by definition) countable.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Cantor introduced the distinction between cardinals and ordinals [Cantor, by Tait]
     Full Idea: Cantor introduced the distinction between cardinal and ordinal numbers.
     From: report of George Cantor (works [1880]) by William W. Tait - Frege versus Cantor and Dedekind Intro
     A reaction: This seems remarkably late for what looks like a very significant clarification. The two concepts coincide in finite cases, but come apart in infinite cases (Tait p.58).
Cantor showed that ordinals are more basic than cardinals [Cantor, by Dummett]
     Full Idea: Cantor's work revealed that the notion of an ordinal number is more fundamental than that of a cardinal number.
     From: report of George Cantor (works [1880]) by Michael Dummett - Frege philosophy of mathematics Ch.23
     A reaction: Dummett makes it sound like a proof, which I find hard to believe. Is the notion that I have 'more' sheep than you logically prior to how many sheep we have? If I have one more, that implies the next number, whatever that number may be. Hm.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / f. Cardinal numbers
A cardinal is an abstraction, from the nature of a set's elements, and from their order [Cantor]
     Full Idea: The cardinal number of M is the general idea which, by means of our active faculty of thought, is deduced from the collection M, by abstracting from the nature of its diverse elements and from the order in which they are given.
     From: George Cantor (works [1880]), quoted by Bertrand Russell - The Principles of Mathematics §284
     A reaction: [Russell cites 'Math. Annalen, XLVI, §1'] See Fine 1998 on this.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
Cantor tried to prove points on a line matched naturals or reals - but nothing in between [Cantor, by Lavine]
     Full Idea: Cantor said he could show that every infinite set of points on the line could be placed into one-to-one correspondence with either the natural numbers or the real numbers - with no intermediate possibilies (the Continuum hypothesis). His proof failed.
     From: report of George Cantor (works [1880]) by Shaughan Lavine - Understanding the Infinite III.1
Cantor's diagonal argument proved you can't list all decimal numbers between 0 and 1 [Cantor, by Read]
     Full Idea: Cantor's diagonal argument showed that all the infinite decimals between 0 and 1 cannot be written down even in a single never-ending list.
     From: report of George Cantor (works [1880]) by Stephen Read - Thinking About Logic Ch.6
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / h. Reals from Cauchy
A real is associated with an infinite set of infinite Cauchy sequences of rationals [Cantor, by Lavine]
     Full Idea: Cantor's theory of Cauchy sequences defines a real number to be associated with an infinite set of infinite sequences of rational numbers.
     From: report of George Cantor (works [1880]) by Shaughan Lavine - Understanding the Infinite II.6
     A reaction: This sounds remarkably like the endless decimals we use when we try to write down an actual real number.
Irrational numbers are the limits of Cauchy sequences of rational numbers [Cantor, by Lavine]
     Full Idea: Cantor introduced irrationals to play the role of limits of Cauchy sequences of rational numbers.
     From: report of George Cantor (works [1880]) by Shaughan Lavine - Understanding the Infinite 4.2
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Irrationals and the Dedekind Cut implied infinite classes, but they seemed to have logical difficulties [Cantor, by Lavine]
     Full Idea: From the very nature of an irrational number, it seems necessary to understand the mathematical infinite thoroughly before an adequate theory of irrationals is possible. Infinite classes are obvious in the Dedekind Cut, but have logical difficulties
     From: report of George Cantor (works [1880]) by Shaughan Lavine - Understanding the Infinite II Intro
     A reaction: Almost the whole theory of analysis (calculus) rested on the irrationals, so a theory of the infinite was suddenly (in the 1870s) vital for mathematics. Cantor wasn't just being eccentric or mystical.
It was Cantor's diagonal argument which revealed infinities greater than that of the real numbers [Cantor, by Lavine]
     Full Idea: Cantor's 1891 diagonal argument revealed there are infinitely many infinite powers. Indeed, it showed more: it shows that given any set there is another of greater power. Hence there is an infinite power strictly greater than that of the set of the reals.
     From: report of George Cantor (works [1880]) by Shaughan Lavine - Understanding the Infinite III.2
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / d. Actual infinite
Cantor proposes that there won't be a potential infinity if there is no actual infinity [Cantor, by Hart,WD]
     Full Idea: What we might call 'Cantor's Thesis' is that there won't be a potential infinity of any sort unless there is an actual infinity of some sort.
     From: report of George Cantor (works [1880]) by William D. Hart - The Evolution of Logic 1
     A reaction: This idea is nicely calculated to stop Aristotle in his tracks.
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / f. Uncountable infinities
The naturals won't map onto the reals, so there are different sizes of infinity [Cantor, by George/Velleman]
     Full Idea: Cantor showed that the complete totality of natural numbers cannot be mapped 1-1 onto the complete totality of the real numbers - so there are different sizes of infinity.
     From: report of George Cantor (works [1880]) by A.George / D.J.Velleman - Philosophies of Mathematics Ch.4
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / g. Continuum Hypothesis
The Continuum Hypothesis says there are no sets between the natural numbers and reals [Cantor, by Shapiro]
     Full Idea: Cantor's 'continuum hypothesis' is the assertion that there are no infinite cardinalities strictly between the size of the natural numbers and the size of the real numbers.
     From: report of George Cantor (works [1880]) by Stewart Shapiro - Thinking About Mathematics 2.4
     A reaction: The tricky question is whether this hypothesis can be proved.
CH: An infinite set of reals corresponds 1-1 either to the naturals or to the reals [Cantor, by Koellner]
     Full Idea: Cantor's Continuum Hypothesis (CH) says that for every infinite set X of reals there is either a one-to-one correspondence between X and the natural numbers, or between X and the real numbers.
     From: report of George Cantor (works [1880]) by Peter Koellner - On the Question of Absolute Undecidability 1.2
     A reaction: Every single writer I read defines this differently, which drives me crazy, but is also helpfully illuminating. There is a moral there somewhere.
Cantor: there is no size between naturals and reals, or between a set and its power set [Cantor, by Hart,WD]
     Full Idea: Cantor conjectured that there is no size between those of the naturals and the reals - called the 'continuum hypothesis'. The generalized version says that for no infinite set A is there a set larger than A but smaller than P(A).
     From: report of George Cantor (works [1880]) by William D. Hart - The Evolution of Logic 1
     A reaction: Thus there are gaps between infinite numbers, and the power set is the next size up from any infinity. Much discussion as ensued about whether these two can be proved.
Cantor's Continuum Hypothesis says there is a gap between the natural and the real numbers [Cantor, by Horsten]
     Full Idea: Cantor's Continuum Hypothesis states that there are no sets which are too large for there to be a one-to-one correspondence between the set and the natural numbers, but too small for there to exist a one-to-one correspondence with the real numbers.
     From: report of George Cantor (works [1880]) by Leon Horsten - Philosophy of Mathematics §5.1
Continuum Hypothesis: there are no sets between N and P(N) [Cantor, by Wolf,RS]
     Full Idea: Cantor's conjecture (the Continuum Hypothesis) is that there are no sets between N and P(N). The 'generalized' version replaces N with an arbitrary infinite set.
     From: report of George Cantor (works [1880]) by Robert S. Wolf - A Tour through Mathematical Logic 2.2
     A reaction: The initial impression is that there is a single gap in the numbers, like a hole in ozone layer, but the generalised version implies an infinity of gaps. How can there be gaps in the numbers? Weird.
Continuum Hypothesis: no cardinal greater than aleph-null but less than cardinality of the continuum [Cantor, by Chihara]
     Full Idea: Cantor's Continuum Hypothesis was that there is no cardinal number greater than aleph-null but less than the cardinality of the continuum.
     From: report of George Cantor (works [1880]) by Charles Chihara - A Structural Account of Mathematics 05.1
     A reaction: I have no view on this (have you?), but the proposal that there are gaps in the number sequences has to excite all philosophers.
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / h. Ordinal infinity
Cantor extended ordinals into the transfinite, and they can thus measure infinite cardinalities [Cantor, by Maddy]
     Full Idea: Cantor's second innovation was to extend the sequence of ordinal numbers into the transfinite, forming a handy scale for measuring infinite cardinalities.
     From: report of George Cantor (works [1880]) by Penelope Maddy - Naturalism in Mathematics I.1
     A reaction: Struggling with this. The ordinals seem to locate the cardinals, but in what sense do they 'measure' them?
Cantor's theory concerns collections which can be counted, using the ordinals [Cantor, by Lavine]
     Full Idea: Cantor's set theory was not of collections in some familiar sense, but of collections that can be counted using the indexes - the finite and transfinite ordinal numbers. ..He treated infinite collections as if they were finite.
     From: report of George Cantor (works [1880]) by Shaughan Lavine - Understanding the Infinite I
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
Cardinality strictly concerns one-one correspondence, to test infinite sameness of size [Cantor, by Maddy]
     Full Idea: Cantor's first innovation was to treat cardinality as strictly a matter of one-to-one correspondence, so that the question of whether two infinite sets are or aren't of the same size suddenly makes sense.
     From: report of George Cantor (works [1880]) by Penelope Maddy - Naturalism in Mathematics I.1
     A reaction: It makes sense, except that all sets which are infinite but countable can be put into one-to-one correspondence with one another. What's that all about, then?
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / e. Caesar problem
Property extensions outstrip objects, so shortage of objects caused the Caesar problem [Cantor, by Shapiro]
     Full Idea: Cantor's theorem entails that there are more property extensions than objects. So there are not enough objects in any domain to serve as extensions for that domain. So Frege's view that numbers are objects led to the Caesar problem.
     From: report of George Cantor (works [1880]) by Stewart Shapiro - Philosophy of Mathematics 4.6
     A reaction: So the possibility that Caesar might have to be a number arises because otherwise we are threatening to run out of numbers? Is that really the problem?
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Pure mathematics is pure set theory [Cantor]
     Full Idea: Pure mathematics ...according to my conception is nothing other than pure set theory.
     From: George Cantor (works [1880], I.1), quoted by Penelope Maddy - Naturalism in Mathematics I.1
     A reaction: [an unpublished paper of 1884] So right at the beginning of set theory this claim was being made, before it was axiomatised, and so on. Zermelo endorsed the view, and it flourished unchallenged until Benacerraf (1965).
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
Cantor says that maths originates only by abstraction from objects [Cantor, by Frege]
     Full Idea: Cantor calls mathematics an empirical science in so far as it begins with consideration of things in the external world; on his view, number originates only by abstraction from objects.
     From: report of George Cantor (works [1880]) by Gottlob Frege - Grundlagen der Arithmetik (Foundations) §21
     A reaction: Frege utterly opposed this view, and he seems to have won the day, but I am rather thrilled to find the great Cantor endorsing my own intuitions on the subject. The difficulty is to explain 'abstraction'.
7. Existence / A. Nature of Existence / 6. Criterion for Existence
Chrysippus says action is the criterion for existence, which must be physical [Chrysippus, by Tieleman]
     Full Idea: Chrysippus regarded power to act and be acted upon as the criterion for existence or being - a test satisfied by bodies alone.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Teun L. Tieleman - Chrysippus
     A reaction: This defines existence in terms of causation. Is he ruling out a priori a particle (say) which exists, but never interacts with anything? If so, he is inclining towards anti-realism.
7. Existence / D. Theories of Reality / 8. Facts / b. Types of fact
There are simple and complex facts; the latter depend on further facts [Chrysippus, by Cicero]
     Full Idea: Chrysippus says there are two classes of facts, simple and complex. An instance of a simple fact is 'Socrates will die at a given date', ...but 'Milo will wrestle at Olympia' is a complex statement, because there can be no wrestling without an opponent.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by M. Tullius Cicero - On Fate ('De fato') 13.30
     A reaction: We might say that there are atomic and complex facts, but our atomic facts tend to be much simpler, usually just saying some object has some property.
7. Existence / E. Categories / 3. Proposed Categories
Stoics categories are Substrate, Quality, Disposition, and Relation [Chrysippus, by Pasnau]
     Full Idea: The Stoics proposed a rather modest categorisation of Substrate, Quality, Disposition, and Relation.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Robert Pasnau - Metaphysical Themes 1274-1671 12.1
8. Modes of Existence / B. Properties / 8. Properties as Modes
If matter is entirely atoms, anything else we notice in it can only be modes [Gassendi]
     Full Idea: Since these atoms are the whole of the corporeal matter or substance that exists in bodies, if we conceive or notice anything else to exist in these bodies, that is not a substance but only some kind of mode of the substance.
     From: Pierre Gassendi (Syntagma [1658], II.1.6.1), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 22.4
     A reaction: If the atoms have a few qualities of their own, are they just modes? If they are genuine powers, then there can be emergent powers, which are rather more than mere 'modes'.
9. Objects / B. Unity of Objects / 3. Unity Problems / b. Cat and its tail
Dion and Theon coexist, but Theon lacks a foot. If Dion loses a foot, he ousts Theon? [Chrysippus, by Philo of Alexandria]
     Full Idea: If two individuals occupied one substance …let one individual (Dion) be thought of as whole-limbed, the other (Theon) as minus one foot. Then let one of Dion's feet be amputated. Theon is the stronger candidate to have perished.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Philo (Alex) - On the Eternity of the World 48
     A reaction: [SVF 2.397 - from Chrysippus's lost 'On the Growing Argument'] This is the original of Tibbles the Cat. Dion must persist to change, and then ousts Theon (it seems). Philo protests at Theon ceasing to exist when nothing has happened to him.
9. Objects / E. Objects over Time / 2. Objects that Change
Change of matter doesn't destroy identity - in Dion and Theon change is a condition of identity [Chrysippus, by Long/Sedley]
     Full Idea: The Growing Argument said any change of matter is a change of identity. Chrysippus presents it with a case (Dion and Theon) where material diminution is the necessary condition of enduring identity, since the diminished footless Dion survives.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by AA Long / DN Sedley - Hellenic Philosophers commentary 28:175
     A reaction: [The example, in Idea 16058, is the original of Tibbles the Cat] This is a lovely bold idea which I haven't met in the modern discussions - that identity actually requires change. The concept of identity is meaningless without change?
14. Science / D. Explanation / 2. Types of Explanation / j. Explanations by reduction
We observe qualities, and use 'induction' to refer to the substances lying under them [Gassendi]
     Full Idea: Nothing beyond qualities is perceived by the senses. …When we refer to the substance in which the qualities inhere, we do this through induction, by which we reason that some subject lies under the quality.
     From: Pierre Gassendi (Syntagma [1658], II.1.6.1), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 07.1
     A reaction: He talks of 'induction' (in an older usage), but he seems to mean abduction, since he never makes any observations of the substances being proposed.
15. Nature of Minds / A. Nature of Mind / 7. Animal Minds
Dogs show reason in decisions made by elimination [Chrysippus, by Sext.Empiricus]
     Full Idea: A dog makes use of the fifth complex indemonstrable syllogism when, arriving at a spot where three ways meet, after smelling at two roads by which the quarry did not pass, he rushes off at once by the third without pausing to smell.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Sextus Empiricus - Outlines of Pyrrhonism I.69
     A reaction: As we might say: either A or B or C; not A; not B; therefore C. I wouldn't want to trust this observation without a lot of analysis of slow-motion photography of dogs as crossroads. Even so, it is a nice challenge to Descartes' view of animals.
16. Persons / F. Free Will / 4. For Free Will
Chrysippus allows evil to say it is fated, or even that it is rational and natural [Plutarch on Chrysippus]
     Full Idea: Chrysippus gives vice blatant freedom to say not only that it is necessary and according to fate, but even that it occurs according to god's reason and the best nature.
     From: comment on Chrysippus (fragments/reports [c.240 BCE]) by Plutarch - 70: Stoic Self-contradictions 1050c
     A reaction: This is Plutarch's criticism of stoic determinism or fatalism. Zeno replied that the punishment for vice may also be fated. It seems that Chysippus did believe that punishments were too harsh, given that vices are fated [p.109].
16. Persons / F. Free Will / 5. Against Free Will
A swerve in the atoms would be unnatural, like scales settling differently for no reason [Chrysippus, by Plutarch]
     Full Idea: Chrysippus argues against the 'swerve' of the Epicureans, on the grounds that they are doing violence to nature by positing something which is uncaused, and cites dice or scales, which can't settle differently without some cause or difference.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Plutarch - 70: Stoic Self-contradictions 1045c
     A reaction: That is, the principle of sufficient reason (or of everything having a cause) is derived from observation, not a priori understanding. Pace Leibniz. As in modern discussion, free will or the swerve only occur in our minds, and not elsewhere.
16. Persons / F. Free Will / 6. Determinism / a. Determinism
Chrysippus is wrong to believe in non-occurring future possibilities if he is a fatalist [Plutarch on Chrysippus]
     Full Idea: Chrysippus's accounts of possibility and fate are in conflict. If he is right that 'everything that permits of occurring even if it is not going to occur is possible', then many things are possible which are not according to fate.
     From: comment on Chrysippus (fragments/reports [c.240 BCE]) by Plutarch - 70: Stoic Self-contradictions 1055e
     A reaction: A palpable hit, I think. Plutarch refers to Chrysippus's rejection of Diodorus Cronus's Master Argument. Fatalism seems to entail that the only future possibilities are the ones that actually occur.
Everything is fated, either by continuous causes or by a supreme rational principle [Chrysippus, by Diog. Laertius]
     Full Idea: Chrysippus says (in his 'On Fate') that everything happens by fate. Fate is a continuous string of causes of things which exist or a rational principle according to which the cosmos is managed.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.148
16. Persons / F. Free Will / 6. Determinism / b. Fate
Fate is an eternal and fixed chain of causal events [Chrysippus]
     Full Idea: Fate is a sempiternal and unchangeable series and chain of things, rolling and unravelling itself through eternal sequences of cause and effect, of which it is composed and compounded.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by Aulus Gellius - Noctes Atticae 7.2.01
     A reaction: It seems that Chrysippus (called by Aulus Gellius 'the chief Stoic philosopher') had a rather grandly rhetorical prose style.
The Lazy Argument responds to fate with 'why bother?', but the bothering is also fated [Chrysippus, by Cicero]
     Full Idea: Chrysippus responded to the Lazy Argument (that the outcome of an illness is fated, so there is no point in calling the doctor) by saying 'calling the doctor is fated just as much as recovering', which he calls 'co-fated'.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by M. Tullius Cicero - On Fate ('De fato') 28-30
     A reaction: From a pragmatic point of view, this idea also nullifies fatalism, since you can plausibly fight against your fate to your last breath. No evidence could ever be offered in support of fatalism, not even the most unlikely events.
When we say events are fated by antecedent causes, do we mean principal or auxiliary causes? [Chrysippus]
     Full Idea: Some causes are perfect and principal, others auxiliary and proximate. Hence when we say that everything takes place by fate owing to antecedent causes, what we wish to be understood is not perfect and principal causes but auxiliary and proximate causes.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by M. Tullius Cicero - On Fate ('De fato') 18.41
     A reaction: This move is described by Cicero as enabling Chrysippus to 'escape necessity and to retain fate'.
16. Persons / F. Free Will / 7. Compatibilism
Destiny is only a predisposing cause, not a sufficient cause [Chrysippus, by Plutarch]
     Full Idea: Chrysippus considered destiny to be not a cause sufficient of itself but only a predisposing cause.
     From: report of Chrysippus (fragments/reports [c.240 BCE], fr 997) by Plutarch - 70: Stoic Self-contradictions 1056b
     A reaction: This appears to be a rejection of determinism, and is the equivalent of Epicurus' introduction of the 'swerve' in atoms. They had suddenly become bothered about the free will problem in about 305 BCE. There must be other non-destiny causes?
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
Infinities expand the bounds of the conceivable; we explore concepts to explore conceivability [Cantor, by Friend]
     Full Idea: Cantor (in his exploration of infinities) pushed the bounds of conceivability further than anyone before him. To discover what is conceivable, we have to enquire into the concept.
     From: report of George Cantor (works [1880]) by Michèle Friend - Introducing the Philosophy of Mathematics 6.5
     A reaction: This remark comes during a discussion of Husserl's phenomenology. Intuitionists challenge Cantor's claim, and restrict what is conceivable to what is provable. Does possibility depend on conceivability?
18. Thought / E. Abstraction / 2. Abstracta by Selection
Cantor says (vaguely) that we abstract numbers from equal sized sets [Hart,WD on Cantor]
     Full Idea: Cantor thought that we abstract a number as something common to all and only those sets any one of which has as many members as any other. ...However one wants to see the logic of the inference. The irony is that set theory lays out this logic.
     From: comment on George Cantor (works [1880]) by William D. Hart - The Evolution of Logic 1
     A reaction: The logic Hart has in mind is the notion of an equivalence relation between sets. This idea sums up the older and more modern concepts of abstraction, the first as psychological, the second as logical (or trying very hard to be!). Cf Idea 9145.
19. Language / D. Propositions / 1. Propositions
A proposition is what can be asserted or denied on its own [Chrysippus]
     Full Idea: A proposition is what can be asserted or denied on its own, for example, 'It is day' or 'Dion is walking'.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by Diogenes Laertius - Lives of Eminent Philosophers 07.65
     A reaction: Note the phrase 'on its own'. If you say 'it is day and Dion is walking', that can't be denied on its own, because first the two halves must each be evaluated, so presumably that doesn't count as a stoic proposition.
20. Action / B. Preliminaries of Action / 2. Willed Action / d. Weakness of will
Passions are judgements; greed thinks money is honorable, and likewise drinking and lust [Chrysippus, by Diog. Laertius]
     Full Idea: Chrysippus says (in his On Passions) that the passions are judgements; for greed is a supposition that money is honorable, and similarly for drunkennes and wantonness and others.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.111
     A reaction: This is an endorsement of Socrates's intellectualist reading of weakness of will, as against Aristotle's assigning it to overpowering passions.
20. Action / C. Motives for Action / 5. Action Dilemmas / c. Omissions
The highest degree of morality performs all that is appropriate, omitting nothing [Chrysippus]
     Full Idea: He who makes moral progress to the highest degree performs all the appropriate actions in all circumstances, and omits none.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by Sophocles - Sophocles' Electra 4.39.22
     A reaction: Hence concerns about omission as well as commission in the practice of ethics can be seen in the light of character and virtue. The world is fully of nice people who act well, but don't do so well on omissions. Car drivers, for example.
21. Aesthetics / C. Artistic Issues / 7. Art and Morality
Stoics say that beauty and goodness are equivalent and linked [Chrysippus, by Diog. Laertius]
     Full Idea: Stoics say the beautiful is the only good. Good is an equivalent term to the beautiful; since a thing is good, it is beautiful; and it is beautiful, therefore it is good.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.1.59
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / g. Moral responsibility
Fate initiates general causes, but individual wills and characters dictate what we do [Chrysippus]
     Full Idea: The order and reason of fate set in motion the general types and starting points of the causes, but each person's own will [or decisions] and the character of his mind govern the impulses of our thoughts and minds and our very actions.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by Aulus Gellius - Noctes Atticae 7.2.11
     A reaction: So if you try and fail it was fate, but if you try and succeed it was you?
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature
Human purpose is to contemplate and imitate the cosmos [Chrysippus]
     Full Idea: The human being was born for the sake of contemplating and imitating the cosmos.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by M. Tullius Cicero - On the Nature of the Gods ('De natura deorum') 2.37
     A reaction: [This seems to be an idea of Chrysippus] Remind me how to imitate the cosmos. Presumably this is living according to nature, but that becomes more obscure when express like this.
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / j. Ethics by convention
Stoics say justice is a part of nature, not just an invented principle [Chrysippus, by Diog. Laertius]
     Full Idea: Stoics say that justice exists by nature, and not because of any definition or principle.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.1.66
     A reaction: cf Idea 3024. Stoics thought that nature is intrinsically rational, and therein lies its justice. 'King Lear' enacts this drama about whether nature is just.
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / k. Ethics from nature
Only nature is available to guide action and virtue [Chrysippus]
     Full Idea: What am I to take as the principle of appropriate action and raw material for virtue if I give up nature and what is according to nature?
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by Plutarch - On Common Conceptions 1069e
     A reaction: 'Nature' is awfully vague as a guideline, even when we are told nature is rational. I can only make sense of it as 'human nature', which is more Aristotelian than stoic. 'Go with the flow' and 'lay the cards you are dealt' might capture it.
22. Metaethics / B. Value / 1. Nature of Value / f. Ultimate value
Live in agreement, according to experience of natural events [Chrysippus]
     Full Idea: The goal of life is to live in agreement, which is according to experience of the things which happen by nature.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by John Stobaeus - Anthology 2.06a
     A reaction: Cleanthes added 'with nature' to Zeno's slogan, and Chyrisppus added this variation. At least it gives you some idea of what the consistent rational principle should be. You still have to assess which aspects of nature should influence us.
22. Metaethics / C. The Good / 1. Goodness / d. Good as virtue
Living happily is nothing but living virtuously [Chrysippus, by Plutarch]
     Full Idea: According to Chrysippus, living happily consists solely in living virtuously.
     From: report of Chrysippus (fragments/reports [c.240 BCE], fr139) by Plutarch - 72: Against Stoics on common Conceptions 1060d
     A reaction: This, along with 'live according to nature', is the essential doctrine of stoicism. This is 'eudaimonia', not the modern idea of feeling nice. Is it possible to admire another person for anything other than virtue? (Yes! Looks, brains, strength, wealth).
22. Metaethics / C. The Good / 1. Goodness / f. Good as pleasure
Pleasure is not the good, because there are disgraceful pleasures [Chrysippus, by Diog. Laertius]
     Full Idea: Pleasure is not the good, because there are disgraceful pleasures, and nothing disgraceful is good.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.Ze.60
     A reaction: I certainly approve of the idea that not all pleasure is intrinsically good. Indeed, I think good has probably got nothing to do with pleasure. 'Disgraceful' is hardly objective though.
Justice can be preserved if pleasure is a good, but not if it is the goal [Chrysippus, by Plutarch]
     Full Idea: Chrysippus thinks that, while justice could not be preserved if one should set up pleasure as the goal, it could be if one should take pleasure to be not a goal but simply a good.
     From: report of Chrysippus (fragments/reports [c.240 BCE], fr 23) by Plutarch - 72: Against Stoics on common Conceptions 1070d
     A reaction: This is an interesting and original contribution to the ancient debate about pleasure. It shows Aristotle's moderate criticism of pleasure (e.g. Idea 84), but attempts to pinpoint where the danger is. Aristotle says it thwarts achievement of the mean.
22. Metaethics / C. The Good / 3. Pleasure / c. Value of pleasure
There are shameful pleasures, and nothing shameful is good, so pleasure is not a good [Chrysippus, by Diog. Laertius]
     Full Idea: Chrysippus (in his On Pleasure) denies even of pleasure that it is a good; for there are also shameful pleasures, and nothing shameful is good.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.103
     A reaction: Socrates seems to have started this line of the thought, to argue that pleasure is not The Good. Stoics are more puritanical. Nothing counts as good if it is capable of being bad. Thus good pleasures are not good, which sounds odd.
23. Ethics / A. Egoism / 2. Hedonism
People need nothing except corn and water [Chrysippus, by Plutarch]
     Full Idea: Chrysippus praises ad nauseam the lines "For what need mortals save two things alone,/ Demeter's grain and draughts of water clear".
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Plutarch - 70: Stoic Self-contradictions 1043e
     A reaction: "Oh, reason not the need!" says King Lear. The remark shows the close affinity of stoicism and cynicism, as the famous story of Diogenes is that he threw away his drinking cup when he realised you could drink with your hands.
23. Ethics / C. Virtue Theory / 1. Virtue Theory / a. Nature of virtue
All virtue is good, but not always praised (as in not lusting after someone ugly) [Chrysippus]
     Full Idea: Although deeds done in accordance with virtue are congenial, not all are cited as examples, such as courageously extending one's finger, or continently abstaining from a half-dead old woman, or not immediately agreeing that three is four.
     From: Chrysippus (fragments/reports [c.240 BCE], fr 211), quoted by Plutarch - 70: Stoic Self-contradictions 1038f
     A reaction: Presumably the point (so elegantly expressed - what a shame we have lost most of Chrysippus) is that virtue comes in degrees, even though its value is an absolute. The same has been said (by Russell and Bonjour) about self-evidence.
23. Ethics / C. Virtue Theory / 1. Virtue Theory / b. Basis of virtue
Chrysippus says virtue can be lost (though Cleanthes says it is too secure for that) [Chrysippus, by Diog. Laertius]
     Full Idea: Chrysippus says that virtue can be lost, owing to drunkenness and excess of black bile, whereas Cleanthes says it cannot, because it consists in secure intellectual grasps, and it is worth choosing for its own sake.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.127
     A reaction: Succumbing to drunkenness looks like evidence that you were not truly virtuous. Mental illness is something else. On the whole I agree the Cleanthes.
Chrysippus says nothing is blameworthy, as everything conforms with the best nature [Chrysippus, by Plutarch]
     Full Idea: Chrysippus has often written on the theme that there is nothing reprehensible or blameworthy in the universe since all things are accomplished in conformity with the best nature.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Plutarch - 70: Stoic Self-contradictions 1051b
     A reaction: This is Leibniz's "best of all possible worlds", but deriving the idea from the rightness of nature rather than the perfection of God. Chrysippus has a more plausible ground than Leibniz, as for him nasty things follow from conscious choice.
24. Political Theory / A. Basis of a State / 1. A People / b. The natural life
Rational animals begin uncorrupted, but externals and companions are bad influences [Chrysippus, by Diog. Laertius]
     Full Idea: The rational animal is corrupted, sometimes because of the persuasiveness of external activities and sometimes because of the influence of companions. For the starting points provided by nature are uncorrupted.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.89
     A reaction: If companions corrupt us, what corrupted the companions? Aren't we all in this together? And where do the 'external activities' originate?
25. Social Practice / D. Justice / 2. The Law / c. Natural law
Justice, the law, and right reason are natural and not conventional [Chrysippus, by Diog. Laertius]
     Full Idea: Chrysippus says (in On the Honourable) that justice is natural and not conventional, as are the law and right reason.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.128
     A reaction: How does he explain variations in the law between different states? Presumably some of them have got it wrong. What is the criterion for deciding which laws are natural?
25. Social Practice / F. Life Issues / 6. Animal Rights
We don't have obligations to animals as they aren't like us [Chrysippus, by Diog. Laertius]
     Full Idea: We have no obligations of justice to other animals, because they are dissimilar to us.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.Ze.66
     A reaction: "Dissimilar" begs questions. Some human beings don't seem much like me. How are we going to treat visiting aliens?
Justice is irrelevant to animals, because they are too unlike us [Chrysippus, by Diog. Laertius]
     Full Idea: There is no justice between us and other animals because of the dissimilarity between us and them.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.129
     A reaction: [from lost On Justice Bk 1] What would he make of modern revelations about bonobos and chimpanzees? If there is great dissimilarity between some peoples, does that invalidate justice between them? He also said animals exist for our use.
26. Natural Theory / A. Speculations on Nature / 2. Natural Purpose / a. Final purpose
Covers are for shields, and sheaths for swords; likewise, all in the cosmos is for some other thing [Chrysippus]
     Full Idea: Just as the cover was made for the sake of the shield, and the sheath for the sword, in the same way everything else except the cosmos was made for the sake of other things.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by M. Tullius Cicero - On the Nature of the Gods ('De natura deorum') 2.37
     A reaction: Chrysippus was wise to stop at the cosmos. Similarly, religious teleology had better not ask about the purpose of God. What does he think pebbles are for? Nature is the source of stoic value, so it needs to be purposeful.
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / f. Ancient elements
The later Stoics identified the logos with an air-fire compound, called 'pneuma' [Chrysippus, by Long]
     Full Idea: From Chrysippus onwards, the Stoics identified the logos throughout each world-cycle not with pure fire, but with a compound of fire and air, 'pneuma'.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by A.A. Long - Hellenistic Philosophy 4.4.2
     A reaction: I suspect this was because breath is so vital to the human body.
Fire is a separate element, not formed with others (as was previously believed) [Chrysippus, by Stobaeus]
     Full Idea: In his theory fire is said independently to be an element, since it is not formed together with another one, whereas according to the earlier theory fire is formed with other elements.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by John Stobaeus - Anthology 1.10.16c
     A reaction: The point is that fire precedes the other elements, and is superior to them.
Stoics say earth, air, fire and water are the primary elements [Chrysippus, by Plutarch]
     Full Idea: The Stoics call the four bodies - earth and water and air and fire - primary elements.
     From: report of Chrysippus (fragments/reports [c.240 BCE], fr 444) by Plutarch - 72: Against Stoics on common Conceptions 1085c
     A reaction: Elsewhere (fr 413) Chrysippus denies that they are all 'primary'. Essentially, though, he seems to be adopting the doctrine of Empedocles and Aristotle, in specific opposition to Epicurus' atomism.
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / g. Atomism
Atoms are not points, but hard indivisible things, which no force in nature can divide [Gassendi]
     Full Idea: The vulgar think atoms lack parts and are free of all magnitude, and hence nothing other than a mathematical point, but it is something solid and hard and compact, as to leave no room for division, separation and cutting. No force in nature can divide it.
     From: Pierre Gassendi (Syntagma [1658], II.1.3.5), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 03.2
     A reaction: If you gloatingly think the atom has now been split, ask whether electrons and quarks now fit his description. Pasnau notes that though atoms are indivisible, they are not incorruptible, and could go out of existence, or be squashed.
How do mere atoms produce qualities like colour, flavour and odour? [Gassendi]
     Full Idea: If the only material principles of things are atoms, having only size, shape, and weight, or motion, then why are so many additional qualities created and existing within the things: color, heat, flavor, odor, and innumerable others?
     From: Pierre Gassendi (Syntagma [1658], II.1.5.7), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 22.4
     A reaction: This is pretty much the 'hard question' about the mind-body relation. Bacon said that heat was just motion of matter. I would say that this problem is gradually being solved in my lifetime.
27. Natural Reality / C. Space / 3. Points in Space
Cantor proved that three dimensions have the same number of points as one dimension [Cantor, by Clegg]
     Full Idea: Cantor proved that one-dimensional space has exactly the same number of points as does two dimensions, or our familiar three-dimensional space.
     From: report of George Cantor (works [1880]) by Brian Clegg - Infinity: Quest to Think the Unthinkable Ch.14
27. Natural Reality / D. Time / 1. Nature of Time / h. Presentism
The past and the future subsist, but only the present exists [Chrysippus, by Plutarch]
     Full Idea: When he wished to be subtle, Chrysippus wrote that the past part of time and the future part do not exist but subsist, and only the present exists.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Plutarch - On Common Conceptions 1081f
     A reaction: [from lost On Void] I think I prefer the ontology of Idea 20818. Idea 20819 does not offer an epistemology. Is the present substantial enough to be known? The word 'subsist' is an ontological evasion (even though Russell briefly relied on it).
27. Natural Reality / D. Time / 3. Parts of Time / e. Present moment
The present does not exist, so our immediate experience is actually part past and part future [Chrysippus, by Plutarch]
     Full Idea: Stoics do not allow a minimal time to exist, and do not want to have a partless 'now'; so what one thinks one has grasped as present is in part future and in part past.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Plutarch - On Common Conceptions 1081c
     A reaction: [from lost On Parts Bk3-5] I agree with the ontology here, but I take our grasp of the present to be very short-term memory of the past. I ignore special relativity. Chrysippus expressed two views about this; in the other one he was a Presentist.
Time is continous and infinitely divisible, so there cannot be a wholly present time [Chrysippus, by Stobaeus]
     Full Idea: Chrysippus says most clearly that no time is wholly present; for since the divisibility of continuous things is infinite, time as a whole is also subject to infinite divisibility by this method of division.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by John Stobaeus - Anthology 1.08.42
     A reaction: But what is his reason for thinking that time is a continuous thing? There is a minimum time in quantum mechanics (the Planck Time), but do these quantum intervals overlap? Compare Idea 20819.
28. God / A. Divine Nature / 2. Divine Nature
Only God is absolutely infinite [Cantor, by Hart,WD]
     Full Idea: Cantor said that only God is absolutely infinite.
     From: report of George Cantor (works [1880]) by William D. Hart - The Evolution of Logic 1
     A reaction: We are used to the austere 'God of the philosophers', but this gives us an even more austere 'God of the mathematicians'.
28. God / A. Divine Nature / 3. Divine Perfections
Stoics say that God the creator is the perfection of all animals [Chrysippus, by Diog. Laertius]
     Full Idea: Stoics say that God is an animal immortal, rational, perfect, and intellectual in his happiness, unsusceptible of any kind of evil, having a foreknowledge of the world; however, he is not the figure of a man, and is the creator of the universe.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.1.72
28. God / A. Divine Nature / 6. Divine Morality / a. Divine morality
The origin of justice can only be in Zeus, and in nature [Chrysippus]
     Full Idea: One can find no other starting point or origin for justice except the one derived from Zeus and that derived from the common nature; for everything like this must have that starting point, if we are going to say anything at all about good and bad things.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by Plutarch - 70: Stoic Self-contradictions 1035c
     A reaction: [in lost 'On Gods' bk 3] This appears to offer two starting points, in the mind of Zeus, and in nature, though since nature is presumed to be rational the two may run together. Is Zeus the embodiment, or the unconscious source, or the maker of decrees?
28. God / A. Divine Nature / 6. Divine Morality / d. God decrees morality
The source of all justice is Zeus and the universal nature [Chrysippus]
     Full Idea: It is not possible to discover any other beginning of justice or any source for it other than that from Zeus and from the universal nature.
     From: Chrysippus (fragments/reports [c.240 BCE], fr 326), quoted by Plutarch - 70: Stoic Self-contradictions 1035c
     A reaction: If the source is 'universal nature', that could agree with Plato, but if the source is Zeus, then stoicism is a religion rather than a philosophy.
Stoics teach that law is identical with right reason, which is the will of Zeus [Chrysippus, by Diog. Laertius]
     Full Idea: Stoics teach that common law is identical with that right reason which pervades everything, being the same with Zeus, who is the regulator and chief manager of all existing things.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.1.53
29. Religion / B. Monotheistic Religion / 1. Monotheistic Religion
Stoics teach that God is a unity, variously known as Mind, or Fate, or Jupiter [Chrysippus, by Diog. Laertius]
     Full Idea: Stoics teach that God is unity, and that he is called Mind, and Fate, and Jupiter, and by many names besides.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.Ze.68
29. Religion / D. Religious Issues / 2. Immortality / b. Soul
Death can't separate soul from body, because incorporeal soul can't unite with body [Chrysippus]
     Full Idea: Death is a separation of soul from body. But nothing incorporeal can be separated from a body. For neither does anything incorporeal touch a body, and the soul touches and is separated from the body. Therefore the soul is not incorporeal.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by Tertullian - The Soul as an 'Astral Body' 5.3
     A reaction: This is the classic interaction difficulty for substance dualist theories of mind.
29. Religion / D. Religious Issues / 3. Problem of Evil / d. Natural Evil
There is a rationale in terrible disasters; they are useful to the whole, and make good possible [Chrysippus]
     Full Idea: The evil which occurs in terrible disasters has a rationale [logos] peculiar to itself: for in a sense it occurs in accordance with universal reason, and is not without usefulness in relation to the whole. For without it there could be no good.
     From: Chrysippus (fragments/reports [c.240 BCE]), quoted by A.A. Long - Hellenistic Philosophy 4.4.5
     A reaction: [a quotation from Chrysippus. Plutarch, Comm Not 1065b] A nice question about any terrible disaster is whether it is in some way 'useful', if we take a broader view of things. Almost everything has a good aspect, from that perspective.