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All the ideas for 'fragments/reports', 'Philosophical Logic' and 'fragments/reports'

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66 ideas

1. Philosophy / A. Wisdom / 2. Wise People
Men who love wisdom must be inquirers into very many things indeed [Heraclitus]
     Full Idea: Men who love wisdom must be inquirers into very many things indeed.
     From: Heraclitus (fragments/reports [c.500 BCE], B035), quoted by Clement - Miscellanies 5.140.5
     A reaction: …which invites the question 'Is there anything that a wisdom-seeker should NOT be interested in?'
1. Philosophy / D. Nature of Philosophy / 2. Invocation to Philosophy
Everyone has the potential for self-knowledge and sound thinking [Heraclitus]
     Full Idea: Everyone has the potential for self-knowledge and sound thinking.
     From: Heraclitus (fragments/reports [c.500 BCE], B116), quoted by John Stobaeus - Anthology 3.05.06
     A reaction: This is true. When people are labelled as incapable of philosophy (e.g. by Plato), it is just that they are slow developers.
1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
Reason is eternal, but men are foolish [Heraclitus]
     Full Idea: Although reason exists forever, men are foolish.
     From: Heraclitus (fragments/reports [c.500 BCE]), quoted by Aristotle - The Art of Rhetoric 1407b
     A reaction: The despair of all philosophers (e.g. Plato) who think reason is the easiest thing in the world, and stares everyone in the face, and yet people seem to spurn this supreme gift from the gods. They needed the optimism of the career teacher.
2. Reason / A. Nature of Reason / 2. Logos
Logos is common to all, but most people live as if they have a private understanding [Heraclitus]
     Full Idea: Although the universal law (logos) is common to all, the majority live as if they had understanding peculiar to themselves.
     From: Heraclitus (fragments/reports [c.500 BCE], B002), quoted by Sextus Empiricus - Against the Professors (six books) 7.133.4-
     A reaction: Heraclitus mentions 'logos' in just three fragments - this one, and Idea 15660 and Idea 424.
2. Reason / B. Laws of Thought / 5. Opposites
A thing can have opposing tensions but be in harmony, like a lyre [Heraclitus]
     Full Idea: They do not understand how that which differs with itself is in agreement: harmony consists of opposing tensions, like that of the bow and the lyre.
     From: Heraclitus (fragments/reports [c.500 BCE], B051), quoted by Hippolytus - Refutation of All Heresies 9.9.2
     A reaction: Like squabbling couples who resent outside intervention. The remark suggests the virtues of 'dialectic', and may get to the heart of what philosophy is.
Beautiful harmony comes from things that are in opposition to one another [Heraclitus]
     Full Idea: That which is in opposition is in concert, and from things that differ comes the beautiful harmony.
     From: Heraclitus (fragments/reports [c.500 BCE], B008), quoted by Aristotle - Nicomachean Ethics 1155b04
4. Formal Logic / D. Modal Logic ML / 6. Temporal Logic
With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess]
     Full Idea: Fand P as 'will' and 'was', G as 'always going to be', H as 'always has been', all tenses reduce to 14 cases: the past series, each implying the next, FH,H,PH,HP,P,GP, and the future series PG,G,FG,GF,F,HF, plus GH=HG implying all, FP=PF which all imply.
     From: John P. Burgess (Philosophical Logic [2009], 2.8)
     A reaction: I have tried to translate the fourteen into English, but am not quite confident enough to publish them here. I leave it as an exercise for the reader.
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
The temporal Barcan formulas fix what exists, which seems absurd [Burgess]
     Full Idea: In temporal logic, if the converse Barcan formula holds then nothing goes out of existence, and the direct Barcan formula holds if nothing ever comes into existence. These results highlight the intuitive absurdity of the Barcan formulas.
     From: John P. Burgess (Philosophical Logic [2009], 2.9)
     A reaction: This is my reaction to the modal cases as well - the absurdity of thinking that no actually nonexistent thing might possibly have existed, or that the actual existents might not have existed. Williamson seems to be the biggest friend of the formulas.
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Is classical logic a part of intuitionist logic, or vice versa? [Burgess]
     Full Idea: From one point of view intuitionistic logic is a part of classical logic, missing one axiom, from another classical logic is a part of intuitionistic logic, missing two connectives, intuitionistic v and →
     From: John P. Burgess (Philosophical Logic [2009], 6.4)
It is still unsettled whether standard intuitionist logic is complete [Burgess]
     Full Idea: The question of the completeness of the full intuitionistic logic for its intended interpretation is not yet fully resolved.
     From: John P. Burgess (Philosophical Logic [2009], 6.9)
4. Formal Logic / E. Nonclassical Logics / 5. Relevant Logic
Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess]
     Full Idea: The relevantist logician's → is perhaps expressible by 'if A, then B, for that reason'.
     From: John P. Burgess (Philosophical Logic [2009], 5.8)
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess]
     Full Idea: Among the more technically oriented a 'logic' no longer means a theory about which forms of argument are valid, but rather means any formalism, regardless of its applications, that resembles original logic enough to be studied by similar methods.
     From: John P. Burgess (Philosophical Logic [2009], Pref)
     A reaction: There doesn't seem to be any great intellectual obligation to be 'technical'. As far as pure logic is concerned, I am very drawn to the computer approach, since I take that to be the original dream of Aristotle and Leibniz - impersonal precision.
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
Classical logic neglects the non-mathematical, such as temporality or modality [Burgess]
     Full Idea: There are topics of great philosophical interest that classical logic neglects because they are not important to mathematics. …These include distinctions of past, present and future, or of necessary, actual and possible.
     From: John P. Burgess (Philosophical Logic [2009], 1.1)
Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess]
     Full Idea: Classical logic neglects counterfactual conditionals for the same reason it neglects temporal and modal distinctions, namely, that they play no serious role in mathematics.
     From: John P. Burgess (Philosophical Logic [2009], 4.1)
     A reaction: Science obviously needs counterfactuals, and metaphysics needs modality. Maybe so-called 'classical' logic will be renamed 'basic mathematical logic'. Philosophy will become a lot clearer when that happens.
The Cut Rule expresses the classical idea that entailment is transitive [Burgess]
     Full Idea: The Cut rule (from A|-B and B|-C, infer A|-C) directly expresses the classical doctrine that entailment is transitive.
     From: John P. Burgess (Philosophical Logic [2009], 5.3)
5. Theory of Logic / A. Overview of Logic / 9. Philosophical Logic
Philosophical logic is a branch of logic, and is now centred in computer science [Burgess]
     Full Idea: Philosophical logic is a branch of logic, a technical subject. …Its centre of gravity today lies in theoretical computer science.
     From: John P. Burgess (Philosophical Logic [2009], Pref)
     A reaction: He firmly distinguishes it from 'philosophy of logic', but doesn't spell it out. I take it that philosophical logic concerns metaprinciples which compare logical systems, and suggest new lines of research. Philosophy of logic seems more like metaphysics.
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
If everything is and isn't then everything is true, and a midway between true and false makes everything false [Aristotle on Heraclitus]
     Full Idea: The remark of Heraclitus that all things are and are not effectively renders all assertions true, and that of Anaxagoras that there is an intermediary between assertion and negation makes all assertions false.
     From: comment on Heraclitus (fragments/reports [c.500 BCE]) by Aristotle - Metaphysics 1012a
     A reaction: Compare Idea 416. Heraclitus is discussing truth-value 'gluts', as in paraconsistent logic, and Anaxagoras is discussing truth-value 'gaps', as in three-valued Kleene logic.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
Formalising arguments favours lots of connectives; proving things favours having very few [Burgess]
     Full Idea: When formalising arguments it is convenient to have as many connectives as possible available.; but when proving results about formulas it is convenient to have as few as possible.
     From: John P. Burgess (Philosophical Logic [2009], 1.4)
     A reaction: Illuminating. The fact that you can whittle classical logic down to two (or even fewer!) connectives warms the heart of technicians, but makes connection to real life much more difficult. Hence a bunch of extras get added.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / e. or
Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess]
     Full Idea: Gricean implicature theory might suggest that a disjunction is never assertable when a disjunct is (though actually the disjunction might be 'pertinent') - but the procedure is indispensable in mathematical practice.
     From: John P. Burgess (Philosophical Logic [2009], 5.2)
     A reaction: He gives an example of a proof in maths which needs it, and an unusual conversational occasion where it makes sense.
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
All occurrences of variables in atomic formulas are free [Burgess]
     Full Idea: All occurrences of variables in atomic formulas are free.
     From: John P. Burgess (Philosophical Logic [2009], 1.7)
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / b. Definite descriptions
The denotation of a definite description is flexible, rather than rigid [Burgess]
     Full Idea: By contrast to rigidly designating proper names, …the denotation of definite descriptions is (in general) not rigid but flexible.
     From: John P. Burgess (Philosophical Logic [2009], 2.9)
     A reaction: This modern way of putting it greatly clarifies why Russell was interested in the type of reference involved in definite descriptions. Obviously some descriptions (such as 'the only person who could ever have…') might be rigid.
5. Theory of Logic / H. Proof Systems / 1. Proof Systems
'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess]
     Full Idea: There are atomic formulas, and formulas built from the connectives, and that is all. We show that all formulas have some property, first for the atomics, then the others. This proof is 'induction on complexity'; we also use 'recursion on complexity'.
     From: John P. Burgess (Philosophical Logic [2009], 1.4)
     A reaction: That is: 'induction on complexity' builds a proof from atomics, via connectives; 'recursion on complexity' breaks down to the atomics, also via the connectives. You prove something by showing it is rooted in simple truths.
5. Theory of Logic / H. Proof Systems / 6. Sequent Calculi
The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess]
     Full Idea: It might be wondered how one could have any kind of proof procedure at all if transitivity of entailment is disallowed, but the sequent calculus can get around the difficulty.
     From: John P. Burgess (Philosophical Logic [2009], 5.3)
     A reaction: He gives examples where transitivity of entailment (so that you can build endless chains of deductions) might fail. This is the point of the 'cut free' version of sequent calculus, since the cut rule allows transitivity.
We can build one expanding sequence, instead of a chain of deductions [Burgess]
     Full Idea: Instead of demonstrations which are either axioms, or follow from axioms by rules, we can have one ever-growing sequence of formulas of the form 'Axioms |- ______', where the blank is filled by Axioms, then Lemmas, then Theorems, then Corollaries.
     From: John P. Burgess (Philosophical Logic [2009], 5.3)
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess]
     Full Idea: The valid formulas of classical sentential logic are called 'tautologically valid', or simply 'tautologies'; with other logics 'tautologies' are formulas that are substitution instances of valid formulas of classical sentential logic.
     From: John P. Burgess (Philosophical Logic [2009], 1.5)
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess]
     Full Idea: Validity (truth by virtue of logical form alone) and demonstrability (provability by virtue of logical form alone) have correlative notions of logical possibility, 'satisfiability' and 'consistency', which come apart in some logics.
     From: John P. Burgess (Philosophical Logic [2009], 3.3)
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
We only need to study mathematical models, since all other models are isomorphic to these [Burgess]
     Full Idea: In practice there is no need to consider any but mathematical models, models whose universes consist of mathematical objects, since every model is isomorphic to one of these.
     From: John P. Burgess (Philosophical Logic [2009], 1.8)
     A reaction: The crucial link is the technique of Gödel Numbering, which can translate any verbal formula into numerical form. He adds that, because of the Löwenheim-Skolem theorem only subsets of the natural numbers need be considered.
Models leave out meaning, and just focus on truth values [Burgess]
     Full Idea: Models generally deliberately leave out meaning, retaining only what is important for the determination of truth values.
     From: John P. Burgess (Philosophical Logic [2009], 2.2)
     A reaction: This is the key point to hang on to, if you are to avoid confusing mathematical models with models of things in the real world.
We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess]
     Full Idea: The aim in setting up a model theory is that the technical notion of truth in all models should agree with the intuitive notion of truth in all instances. A model is supposed to represent everything about an instance that matters for its truth.
     From: John P. Burgess (Philosophical Logic [2009], 3.2)
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess]
     Full Idea: It is a common view that the liar sentence ('This very sentence is not true') is an instance of a truth-value gap (neither true nor false), but some dialethists cite it as an example of a truth-value glut (both true and false).
     From: John P. Burgess (Philosophical Logic [2009], 5.7)
     A reaction: The defence of the glut view must be that it is true, then it is false, then it is true... Could it manage both at once?
8. Modes of Existence / C. Powers and Dispositions / 4. Powers as Essence
The hidden harmony is stronger than the visible [Heraclitus]
     Full Idea: The hidden harmony is stronger (or 'better') than the visible.
     From: Heraclitus (fragments/reports [c.500 BCE], B055), quoted by Hippolytus - Refutation of All Heresies 9.9.5
     A reaction: 'An unapparent connection [harmonia] is stronger than an apparent one' is Curd's translation. I'm taking this for essentialism. It is the basic idea of the essentialising child (see Gelman). The hidden explains the apparent.
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
Everything gives way, and nothing stands fast [Heraclitus]
     Full Idea: Everything gives way, and nothing stands fast.
     From: Heraclitus (fragments/reports [c.500 BCE]), quoted by Plato - Cratylus 402a
     A reaction: This is as good a summary of the Heraclitus view of things as any, and Plato appears to present it as a verbatim quotation.
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
A mixed drink separates if it is not stirred [Heraclitus]
     Full Idea: The mixed drink, of wine, cheese and barley, separates if it is not stirred.
     From: Heraclitus (fragments/reports [c.500 BCE], B125)
     A reaction: Wiggins quotes this, because it seems to be Heraclitus struggling to decide what sortal his drink falls under. I take it to be a problem of vagueness, since separation and mixing occur along a continuum, like a sorites.
9. Objects / E. Objects over Time / 8. Continuity of Rivers
It is not possible to step twice into the same river [Heraclitus]
     Full Idea: It is not possible to step twice into the same river.
     From: Heraclitus (fragments/reports [c.500 BCE], B091), quoted by Plutarch - 24: The E at Delphi 392b10-
You can bathe in the same river twice, but not in the same river stage [Quine on Heraclitus]
     Full Idea: You can bathe in the same river twice, but not in the same river stage.
     From: comment on Heraclitus (fragments/reports [c.500 BCE]) by Willard Quine - Identity, Ostension, and Hypostasis 1
     A reaction: This seems to make Quine a 'perdurantist', committed to time-slices of objects, rather than whole objects enduring through change.
9. Objects / E. Objects over Time / 13. No Identity over Time
If flux is continuous, then lack of change can't be a property, so everything changes in every possible way [Plato on Heraclitus]
     Full Idea: According to Heracliteans, since things must be changing, and since lack of change can't be a property of anything, then everything is always undergoing change of every kind.
     From: comment on Heraclitus (fragments/reports [c.500 BCE], B030) by Plato - Theaetetus 182a
10. Modality / A. Necessity / 4. De re / De dicto modality
De re modality seems to apply to objects a concept intended for sentences [Burgess]
     Full Idea: There is a problem over 'de re' modality (as contrasted with 'de dicto'), as in ∃x□x. What is meant by '"it is analytic that Px" is satisfied by a', given that analyticity is a notion that in the first instance applies to complete sentences?
     From: John P. Burgess (Philosophical Logic [2009], 3.9)
     A reaction: This is Burgess's summary of one of Quine's original objections. The issue may be a distinction between whether the sentence is analytic, and what makes it analytic. The necessity of bachelors being unmarried makes that sentence analytic.
10. Modality / A. Necessity / 6. Logical Necessity
General consensus is S5 for logical modality of validity, and S4 for proof [Burgess]
     Full Idea: To the extent that there is any conventional wisdom about the question, it is that S5 is correct for alethic logical modality, and S4 correct for apodictic logical modality.
     From: John P. Burgess (Philosophical Logic [2009], 3.8)
     A reaction: In classical logic these coincide, so presumably one should use the minimum system to do the job, which is S4 (?).
Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess]
     Full Idea: Logical necessity is a genus with two species. For classical logic the truth-related notion of validity and the proof-related notion of demonstrability, coincide - but they are distinct concept. In some logics they come apart, in intension and extension.
     From: John P. Burgess (Philosophical Logic [2009], 3.3)
     A reaction: They coincide in classical logic because it is sound and complete. This strikes me as the correct approach to logical necessity, tying it to the actual nature of logic, rather than some handwavy notion of just 'true in all possible worlds'.
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess]
     Full Idea: Three main theories of the truth of indicative conditionals are Materialism (the conditions are the same as for the material conditional), Idealism (identifying assertability with truth-value), and Nihilism (no truth, just assertability).
     From: John P. Burgess (Philosophical Logic [2009], 4.3)
It is doubtful whether the negation of a conditional has any clear meaning [Burgess]
     Full Idea: It is contentious whether conditionals have negations, and whether 'it is not the case that if A,B' has any clear meaning.
     From: John P. Burgess (Philosophical Logic [2009], 4.9)
     A reaction: This seems to be connected to Lewis's proof that a probability conditional cannot be reduced to a single proposition. If a conditional only applies to A-worlds, it is not surprising that its meaning gets lost when it leaves that world.
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Senses are no use if the soul is corrupt [Heraclitus]
     Full Idea: The eyes and ears are bad witnesses for men if they have barbarian souls.
     From: Heraclitus (fragments/reports [c.500 BCE], B107), quoted by Sextus Empiricus - Against the Mathematicians 7.126
12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism
When we sleep, reason closes down as the senses do [Heraclitus, by Sext.Empiricus]
     Full Idea: Since when we sleep the senses are closed, mind is separated from its surroundings and loses the power of memory. When we wake the mind re-contacts the world, and regains the power of reason.
     From: report of Heraclitus (fragments/reports [c.500 BCE], A16) by Sextus Empiricus - Against the Professors (six books) 7.130
13. Knowledge Criteria / E. Relativism / 1. Relativism
Donkeys prefer chaff to gold [Heraclitus]
     Full Idea: Donkeys prefer chaff to gold.
     From: Heraclitus (fragments/reports [c.500 BCE], B009), quoted by Aristotle - Nicomachean Ethics 1176a07
Sea water is life-giving for fish, but not for people [Heraclitus]
     Full Idea: Sea-water is the purest and the most polluted: for fish it is drinkable and life-giving; for men, not drinkable and destructive.
     From: Heraclitus (fragments/reports [c.500 BCE], B061), quoted by Hippolytus - Refutation of All Heresies 9.10.5
13. Knowledge Criteria / E. Relativism / 3. Subjectivism
Health, feeding and rest are only made good by disease, hunger and weariness [Heraclitus]
     Full Idea: Disease makes health pleasant and good, hunger makes satisfaction good, weariness makes rest good.
     From: Heraclitus (fragments/reports [c.500 BCE], B111), quoted by John Stobaeus - Anthology 3.1.178
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / e. Ethical cognitivism
To God (though not to humans) all things are beautiful and good and just [Heraclitus]
     Full Idea: To God, all things are beautiful, good and just; but men have assumed some things to be unjust, others just.
     From: Heraclitus (fragments/reports [c.500 BCE], B102), quoted by Porphyry - Notes on Homer Il.4.4
     A reaction: The idea that all things are actually 'just' strikes me as nonsense. I also don't think I can get my head round the idea that everything is actually good and beautiful. Must try harder.
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / h. Against ethics
Good and evil are the same thing [Heraclitus, by Aristotle]
     Full Idea: Heraclitus said that good and evil are the same thing.
     From: report of Heraclitus (fragments/reports [c.500 BCE], 58/102) by Aristotle - Topics 159b32
     A reaction: Heaven knows what he meant by this, though it sounds suspiciously like moral nihilism. Maybe Heraclitus was not a very nice man. Or is the thought a more sophisticated one, in line with Nietzsche's remarks about cultural morality?
22. Metaethics / B. Value / 1. Nature of Value / e. Means and ends
If one does not hope, one will not find the unhoped-for, since nothing leads to it [Heraclitus]
     Full Idea: If one does not hope, one will not find the unhoped-for, since there is no trail leading to it and no path.
     From: Heraclitus (fragments/reports [c.500 BCE], B018), quoted by Clement - Miscellanies 2.17.4
     A reaction: The best remark about hope I have ever encountered. Usually they are empty platitudes.
22. Metaethics / C. The Good / 1. Goodness / f. Good as pleasure
If happiness is bodily pleasure, then oxen are happy when they have vetch to eat [Heraclitus]
     Full Idea: If happiness lay in bodily pleasures, we would call oxen happy when they find vetch to eat.
     From: Heraclitus (fragments/reports [c.500 BCE], B004), quoted by Albertus Magnus - On Vegetables 6.401
     A reaction: But surely oxen are happy when they find some good vetch? Presumably, though, they are not 'eudaimon'. What is the complete fulfilment of life for an ox?
22. Metaethics / C. The Good / 3. Pleasure / f. Dangers of pleasure
It is hard to fight against emotion, but harder still to fight against pleasure [Heraclitus]
     Full Idea: It is hard to fight against emotion, but harder still to fight against pleasure.
     From: Heraclitus (fragments/reports [c.500 BCE], B085), quoted by Aristotle - Nicomachean Ethics 1105a08
     A reaction: 'Emotion' is the Greek word 'thumos'. "The only way to get rid of a temptation is to yield to it", said Oscar Wilde. Heraclitus underestimates how very good many modern people are at dieting.
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / e. Character
For man character is destiny [Heraclitus]
     Full Idea: For man character is destiny.
     From: Heraclitus (fragments/reports [c.500 BCE], B119), quoted by John Stobaeus - Anthology 4.40.23
     A reaction: This is the extreme opposite of Sartre's existentialist claim that we can entirely change ourselves. Personally I am with Heraclitus, though I don't see why our destined character shouldn't be modified (e.g. by education).
25. Social Practice / D. Justice / 2. The Law / b. Rule of law
The people should fight for the law as if for their city-wall [Heraclitus]
     Full Idea: The people should fight for the law as if for their city-wall.
     From: Heraclitus (fragments/reports [c.500 BCE], B044), quoted by Diogenes Laertius - Lives of Eminent Philosophers 09.2
     A reaction: This may be the first recorded assertion of the rule of law, and hence of the separation of powers. We still have plenty of people who reject this principle.
26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature
Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius]
     Full Idea: Archelaus was the first person to say that the universe is boundless.
     From: report of Archelaus (fragments/reports [c.450 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 02.Ar.3
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / c. Ultimate substances
Heraclitus said sometimes everything becomes fire [Heraclitus, by Aristotle]
     Full Idea: Heraclitus claimed that from time to time everything becomes fire.
     From: report of Heraclitus (fragments/reports [c.500 BCE]) by Aristotle - Metaphysics 1067a
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / e. The One
Reason tells us that all things are one [Heraclitus]
     Full Idea: When you have listened, not to me but to the law (logos), it is wise to agree that all things are one.
     From: Heraclitus (fragments/reports [c.500 BCE], B050), quoted by Hippolytus - Refutation of All Heresies 9.9.1
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / f. Ancient elements
Heraclitus says that at some time everything becomes fire [Heraclitus, by Aristotle]
     Full Idea: Heraclitus says that at some time everything becomes fire.
     From: report of Heraclitus (fragments/reports [c.500 BCE]) by Aristotle - Physics 204b37
     A reaction: Modern cosmology says that Heraclitus was right (pretty much). If we say 'energy' instead of 'fire' (which may be what he meant), then he is absolutely spot-on.
The sayings of Heraclitus are still correct, if we replace 'fire' with 'energy' [Heraclitus, by Heisenberg]
     Full Idea: If we replace Heraclitus's word 'fire' by the word 'energy' we can almost repeat his statements word for word from our modern point of view.
     From: report of Heraclitus (fragments/reports [c.500 BCE]) by Werner Heisenberg - Physics and Philosophy 04
     A reaction: My problem has always been that I have no idea what 'energy' is, so I'm none the wiser.
Heraclitus said fire could be transformed to create the other lower elements [Heraclitus, by Diog. Laertius]
     Full Idea: Heraclitus taught that fire when densified becomes liquid, and becoming concrete, becomes also water; again, that the water when concrete is turned to earth, and this is the road down.
     From: report of Heraclitus (fragments/reports [c.500 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.1.6
26. Natural Theory / B. Natural Kinds / 4. Source of Kinds
Logos is the source of everything, and my theories separate and explain each nature [Heraclitus]
     Full Idea: All things come into being according to this Law ('logos'), ...and I expound theories (words) and processes (actions) separating each thing according to its nature and explaining how it is made.
     From: Heraclitus (fragments/reports [c.500 BCE], B001), quoted by Sextus Empiricus - Against the Mathematicians 7.133
     A reaction: I like the fact that things are separated according to their natures (particulars!), and not that natures are somehow bestowed on individuals.
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
All things are in a state of motion [Heraclitus, by Aristotle]
     Full Idea: All things are in a state of motion.
     From: report of Heraclitus (fragments/reports [c.500 BCE]) by Aristotle - Topics 104b22
     A reaction: This seems right, I would say. It seems to make a 'process' the fundamental category of ontology, rather than an 'object'.
27. Natural Reality / E. Cosmology / 2. Eternal Universe
The cosmos is eternal not created, and is an ever-living and changing fire [Heraclitus]
     Full Idea: This cosmos, which is the same for all, was not created by any one of the gods or of mankind, but it was ever and is and shall be ever-living fire, kindled and quenched in measure.
     From: Heraclitus (fragments/reports [c.500 BCE], B030), quoted by Clement - Miscellanies 5.1.103
27. Natural Reality / G. Biology / 3. Evolution
Archelaus said life began in a primeval slime [Archelaus, by Schofield]
     Full Idea: Archelaus wrote that life on Earth began in a primeval slime.
     From: report of Archelaus (fragments/reports [c.450 BCE]) by Malcolm Schofield - Archelaus
     A reaction: This sounds like a fairly clearcut assertion of the production of life by evolution. Darwin's contribution was to propose the mechanism for achieving it. We should honour the name of Archelaus for this idea.
28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
Heraclitus says intelligence draws on divine reason [Heraclitus, by Sext.Empiricus]
     Full Idea: According to Heraclitus we become intelligent by drawing on divine reason.
     From: report of Heraclitus (fragments/reports [c.500 BCE], A16) by Sextus Empiricus - Against the Professors (six books) 7.129
29. Religion / A. Polytheistic Religion / 2. Greek Polytheism
Purifying yourself with blood is as crazy as using mud to wash off mud [Heraclitus]
     Full Idea: They purify themselves by staining themselves with other blood, as if one were to step into mud to wash off mud. But a man would be thought mad if any of his fellow-men should perceive him acting thus.
     From: Heraclitus (fragments/reports [c.500 BCE], B005), quoted by Origen - Against Celsus 7.62
29. Religion / D. Religious Issues / 1. Religious Commitment / a. Religious Belief
In their ignorance people pray to statues, which is like talking to a house [Heraclitus]
     Full Idea: In their ignorance of the true nature of gods and heroes people pray to these statues, which is like someone holding a conversation with a house.
     From: Heraclitus (fragments/reports [c.500 BCE], B005), quoted by Anon (Pyth) - Theosophia Tubigensis 68