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All the ideas for 'The Evolution of Logic', 'Principia Mathematica' and 'works'

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111 ideas

1. Philosophy / A. Wisdom / 1. Nature of Wisdom
There is practical wisdom (for action), and theoretical wisdom (for deep understanding) [Aristotle, by Whitcomb]
     Full Idea: Aristotle takes wisdom to come in two forms, the practical and the theoretical, the former of which is good judgement about how to act, and the latter of which is deep knowledge or understanding.
     From: report of Aristotle (works [c.330 BCE]) by Dennis Whitcomb - Wisdom Intro
     A reaction: The interesting question is then whether the two are connected. One might be thoroughly 'sensible' about action, without counting as 'wise', which seems to require a broader view of what is being done. Whitcomb endorses Aristotle on this idea.
1. Philosophy / C. History of Philosophy / 4. Later European Philosophy / c. Eighteenth century philosophy
We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD]
     Full Idea: We are all post-Kantians, ...because Kant set an agenda for philosophy that we are still working through.
     From: William D. Hart (The Evolution of Logic [2010], 2)
     A reaction: Hart says that the main agenda is set by Kant's desire to defend the principle of sufficient reason against Hume's attack on causation. I would take it more generally to be the assessment of metaphysics, and of a priori knowledge.
1. Philosophy / D. Nature of Philosophy / 1. Philosophy
Philosophy must abstract from the senses [Newton]
     Full Idea: In philosophy abstraction from the senses is required.
     From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol)
     A reaction: He particularly means 'natural philosophy' (i.e. science), but there is no real distinction in Newton's time, and I would say this remark is true of modern philosophy.
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / d. Philosophy as puzzles
The problems are the monuments of philosophy [Hart,WD]
     Full Idea: The real monuments of philosophy are its problems.
     From: William D. Hart (The Evolution of Logic [2010], 2)
     A reaction: Presumably he means '....rather than its solutions'. No other subject would be very happy with that sort of claim. Compare Idea 8243. A complaint against analytic philosophy is that it has achieved no consensus at all.
1. Philosophy / F. Analytic Philosophy / 6. Logical Analysis
To study abstract problems, some knowledge of set theory is essential [Hart,WD]
     Full Idea: By now, no education in abstract pursuits is adequate without some familiarity with sets.
     From: William D. Hart (The Evolution of Logic [2010], 10)
     A reaction: A heart-sinking observation for those who aspire to study metaphysics and modality. The question is, what will count as 'some' familiarity? Are only professional logicians now allowed to be proper philosophers?
2. Reason / A. Nature of Reason / 2. Logos
For Aristotle logos is essentially the ability to talk rationally about questions of value [Roochnik on Aristotle]
     Full Idea: For Aristotle logos is the ability to speak rationally about, with the hope of attaining knowledge, questions of value.
     From: comment on Aristotle (works [c.330 BCE]) by David Roochnik - The Tragedy of Reason p.26
2. Reason / A. Nature of Reason / 4. Aims of Reason
Aristotle is the supreme optimist about the ability of logos to explain nature [Roochnik on Aristotle]
     Full Idea: Aristotle is the great theoretician who articulates a vision of a world in which natural and stable structures can be rationally discovered. His is the most optimistic and richest view of the possibilities of logos
     From: comment on Aristotle (works [c.330 BCE]) by David Roochnik - The Tragedy of Reason p.95
2. Reason / D. Definition / 4. Real Definition
Aristotelian definitions aim to give the essential properties of the thing defined [Aristotle, by Quine]
     Full Idea: A real definition, according to the Aristotelian tradition, gives the essence of the kind of thing defined. Man is defined as a rational animal, and thus rationality and animality are of the essence of each of us.
     From: report of Aristotle (works [c.330 BCE]) by Willard Quine - Vagaries of Definition p.51
     A reaction: Compare Idea 4385. Personally I prefer the Aristotelian approach, but we may have to say 'We cannot identify the essence of x, and so x cannot be defined'. Compare 'his mood was hard to define' with 'his mood was hostile'.
2. Reason / D. Definition / 5. Genus and Differentia
Aristotelian definition involves first stating the genus, then the differentia of the thing [Aristotle, by Urmson]
     Full Idea: For Aristotle, to give a definition one must first state the genus and then the differentia of the kind of thing to be defined.
     From: report of Aristotle (works [c.330 BCE]) by J.O. Urmson - Aristotle's Doctrine of the Mean p.157
     A reaction: Presumably a modern definition would just be a list of properties, but Aristotle seeks the substance. How does he define a genus? - by placing it in a further genus?
3. Truth / C. Correspondence Truth / 2. Correspondence to Facts
Tarski showed how we could have a correspondence theory of truth, without using 'facts' [Hart,WD]
     Full Idea: It is an ancient and honourable view that truth is correspondence to fact; Tarski showed us how to do without facts here.
     From: William D. Hart (The Evolution of Logic [2010], 2)
     A reaction: This is a very interesting spin on Tarski, who certainly seems to endorse the correspondence theory, even while apparently inventing a new 'semantic' theory of truth. It is controversial how far Tarski's theory really is a 'correspondence' theory.
3. Truth / F. Semantic Truth / 1. Tarski's Truth / b. Satisfaction and truth
Truth for sentences is satisfaction of formulae; for sentences, either all sequences satisfy it (true) or none do [Hart,WD]
     Full Idea: We explain truth for sentences in terms of satisfaction of formulae. The crux here is that for a sentence, either all sequences satisfy it or none do (with no middle ground). For formulae, some sequences may satisfy it and others not.
     From: William D. Hart (The Evolution of Logic [2010], 4)
     A reaction: This is the hardest part of Tarski's theory of truth to grasp.
3. Truth / F. Semantic Truth / 2. Semantic Truth
A first-order language has an infinity of T-sentences, which cannot add up to a definition of truth [Hart,WD]
     Full Idea: In any first-order language, there are infinitely many T-sentences. Since definitions should be finite, the agglomeration of all the T-sentences is not a definition of truth.
     From: William D. Hart (The Evolution of Logic [2010], 4)
     A reaction: This may be a warning shot aimed at Davidson's extensive use of Tarski's formal account in his own views on meaning in natural language.
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL
Conditional Proof: infer a conditional, if the consequent can be deduced from the antecedent [Hart,WD]
     Full Idea: A 'conditional proof' licenses inferences to a conditional from a deduction of its consequent from its antecedent.
     From: William D. Hart (The Evolution of Logic [2010], 4)
     A reaction: That is, a proof can be enshrined in an arrow.
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / e. Existential quantifier ∃
∃y... is read as 'There exists an individual, call it y, such that...', and not 'There exists a y such that...' [Hart,WD]
     Full Idea: When a quantifier is attached to a variable, as in '∃(y)....', then it should be read as 'There exists an individual, call it y, such that....'. One should not read it as 'There exists a y such that...', which would attach predicate to quantifier.
     From: William D. Hart (The Evolution of Logic [2010], 4)
     A reaction: The point is to make clear that in classical logic the predicates attach to the objects, and not to some formal component like a quantifier.
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Set theory articulates the concept of order (through relations) [Hart,WD]
     Full Idea: It is set theory, and more specifically the theory of relations, that articulates order.
     From: William D. Hart (The Evolution of Logic [2010])
     A reaction: It would seem that we mainly need set theory in order to talk accurately about order, and about infinity. The two come together in the study of the ordinal numbers.
Nowadays ZFC and NBG are the set theories; types are dead, and NF is only useful for the whole universe [Hart,WD]
     Full Idea: The theory of types is a thing of the past. There is now nothing to choose between ZFC and NBG (Neumann-Bernays-Gödel). NF (Quine's) is a more specialized taste, but is a place to look if you want the universe.
     From: William D. Hart (The Evolution of Logic [2010], 3)
4. Formal Logic / F. Set Theory ST / 2. Mechanics of Set Theory / a. Symbols of ST
∈ relates across layers, while ⊆ relates within layers [Hart,WD]
     Full Idea: ∈ relates across layers (Plato is a member of his unit set and the set of people), while ⊆ relates within layers (the singleton of Plato is a subset of the set of people). This distinction only became clear in the 19th century.
     From: William D. Hart (The Evolution of Logic [2010], 1)
     A reaction: Getting these two clear may be the most important distinction needed to understand how set theory works.
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
Without the empty set we could not form a∩b without checking that a and b meet [Hart,WD]
     Full Idea: Without the empty set, disjoint sets would have no intersection, and we could not form a∩b without checking that a and b meet. This is an example of the utility of the empty set.
     From: William D. Hart (The Evolution of Logic [2010], 1)
     A reaction: A novice might plausibly ask why there should be an intersection for every pair of sets, if they have nothing in common except for containing this little puff of nothingness. But then what do novices know?
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / i. Axiom of Foundation VIII
In the modern view, foundation is the heart of the way to do set theory [Hart,WD]
     Full Idea: In the second half of the twentieth century there emerged the opinion that foundation is the heart of the way to do set theory.
     From: William D. Hart (The Evolution of Logic [2010], 3)
     A reaction: It is foundation which is the central axiom of the iterative conception of sets, where each level of sets is built on previous levels, and they are all 'well-founded'.
Foundation Axiom: an nonempty set has a member disjoint from it [Hart,WD]
     Full Idea: The usual statement of Foundation is that any nonempty set has a member disjoint from it. This phrasing is ordinal-free and closer to the primitives of ZFC.
     From: William D. Hart (The Evolution of Logic [2010], 3)
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
We can choose from finite and evident sets, but not from infinite opaque ones [Hart,WD]
     Full Idea: When a set is finite, we can prove it has a choice function (∀x x∈A → f(x)∈A), but we need an axiom when A is infinite and the members opaque. From infinite shoes we can pick a left one, but from socks we need the axiom of choice.
     From: William D. Hart (The Evolution of Logic [2010], 1)
     A reaction: The socks example in from Russell 1919:126.
With the Axiom of Choice every set can be well-ordered [Hart,WD]
     Full Idea: It follows from the Axiom of Choice that every set can be well-ordered.
     From: William D. Hart (The Evolution of Logic [2010], 1)
     A reaction: For 'well-ordered' see Idea 13460. Every set can be ordered with a least member.
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / o. Axiom of Constructibility V = L
If we accept that V=L, it seems to settle all the open questions of set theory [Hart,WD]
     Full Idea: It has been said (by Burt Dreben) that the only reason set theorists do not generally buy the view that V = L is that it would put them out of business by settling their open questions.
     From: William D. Hart (The Evolution of Logic [2010], 10)
     A reaction: Hart says V=L breaks with the interative conception of sets at level ω+1, which is countable is the constructible view, but has continuum many in the cumulative (iterative) hierarch. The constructible V=L view is anti-platonist.
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / d. Naïve logical sets
Naïve set theory has trouble with comprehension, the claim that every predicate has an extension [Hart,WD]
     Full Idea: 'Comprehension' is the assumption that every predicate has an extension. Naïve set theory is the theory whose axioms are extensionality and comprehension, and comprehension is thought to be its naivety.
     From: William D. Hart (The Evolution of Logic [2010], 1)
     A reaction: This doesn't, of course, mean that there couldn't be a more modest version of comprehension. The notorious difficulty come with the discovery of self-referring predicates which can't possibly have extensions.
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / e. Iterative sets
The iterative conception may not be necessary, and may have fixed points or infinitely descending chains [Hart,WD]
     Full Idea: That the iterative sets suffice for most of ZFC does not show they are necessary, nor is it evident that the set of operations has no fixed points (as 0 is a fixed point for square-of), and no infinitely descending chains (like negative integers).
     From: William D. Hart (The Evolution of Logic [2010], 3)
     A reaction: People don't seem to worry that they aren't 'necessary', and further measures are possible to block infinitely descending chains.
4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets
A 'partial ordering' is irreflexive and transitive; the sets are ordered, but not the subsets [Hart,WD]
     Full Idea: We say that a binary relation R 'partially orders' a field A just in case R is irreflexive (so that nothing bears R to itself) and transitive. When the set is {a,b}, its subsets {a} and {b} are incomparable in a partial ordering.
     From: William D. Hart (The Evolution of Logic [2010], 1)
A partial ordering becomes 'total' if any two members of its field are comparable [Hart,WD]
     Full Idea: A partial ordering is a 'total ordering' just in case any two members of its field are comparable, that is, either a is R to b, or b is R to a, or a is b.
     From: William D. Hart (The Evolution of Logic [2010], 1)
     A reaction: See Idea 13457 for 'partial ordering'. The three conditions are known as the 'trichotomy' condition.
'Well-ordering' must have a least member, so it does the natural numbers but not the integers [Hart,WD]
     Full Idea: A total order 'well-orders' its field just in case any nonempty subset B of its field has an R-least member, that is, there is a b in B such that for any a in B different from b, b bears R to a. So less-than well-orders natural numbers, but not integers.
     From: William D. Hart (The Evolution of Logic [2010], 1)
     A reaction: The natural numbers have a starting point, but the integers are infinite in both directions. In plain English, an order is 'well-ordered' if there is a starting point.
Von Neumann defines α<β as α∈β [Hart,WD]
     Full Idea: One of the glories of Von Neumann's theory of numbers is to define α < β to mean that α ∈ β.
     From: William D. Hart (The Evolution of Logic [2010], 3)
4. Formal Logic / F. Set Theory ST / 8. Critique of Set Theory
Maybe sets should be rethought in terms of the even more basic categories [Hart,WD]
     Full Idea: Some have claimed that sets should be rethought in terms of still more basic things, categories.
     From: William D. Hart (The Evolution of Logic [2010], 2)
     A reaction: [He cites F.William Lawvere 1966] It appears to the the context of foundations for mathematics that he has in mind.
4. Formal Logic / G. Formal Mereology / 1. Mereology
Aristotle relativises the notion of wholeness to different measures [Aristotle, by Koslicki]
     Full Idea: Aristotle proposes to relativise unity and plurality, so that a single object can be both one (indivisible) and many (divisible) simultaneously, without contradiction, relative to different measures. Wholeness has degrees, with the strength of the unity.
     From: report of Aristotle (works [c.330 BCE]) by Kathrin Koslicki - The Structure of Objects 7.2.12
     A reaction: [see Koslicki's account of Aristotle for details] As always, the Aristotelian approach looks by far the most promising. Simplistic mechanical accounts of how parts make wholes aren't going to work. We must include the conventional and conceptual bit.
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
For Aristotle, the subject-predicate structure of Greek reflected a substance-accident structure of reality [Aristotle, by O'Grady]
     Full Idea: Aristotle apparently believed that the subject-predicate structure of Greek reflected the substance-accident nature of reality.
     From: report of Aristotle (works [c.330 BCE]) by Paul O'Grady - Relativism Ch.4
     A reaction: We need not assume that Aristotle is wrong. It is a chicken-and-egg. There is something obvious about subject-predicate language, if one assumes that unified objects are part of nature, and not just conventional.
5. Theory of Logic / G. Quantification / 3. Objectual Quantification
The universal quantifier can't really mean 'all', because there is no universal set [Hart,WD]
     Full Idea: All the main set theories deny that there is a set of which everything is a member. No interpretation has a domain with everything in it. So the universal quantifier never gets to mean everything all at once; 'all' does not mean all.
     From: William D. Hart (The Evolution of Logic [2010], 4)
     A reaction: Could you have an 'uncompleted' universal set, in the spirit of uncompleted infinities? In ordinary English we can talk about 'absolutely everything' - we just can't define a set of everything. Must we 'define' our domain?
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Modern model theory begins with the proof of Los's Conjecture in 1962 [Hart,WD]
     Full Idea: The beginning of modern model theory was when Morley proved Los's Conjecture in 1962 - that a complete theory in a countable language categorical in one uncountable cardinal is categorical in all.
     From: William D. Hart (The Evolution of Logic [2010], 9)
Model theory studies how set theory can model sets of sentences [Hart,WD]
     Full Idea: Modern model theory investigates which set theoretic structures are models for which collections of sentences.
     From: William D. Hart (The Evolution of Logic [2010], 4)
     A reaction: So first you must choose your set theory (see Idea 13497). Then you presumably look at how to formalise sentences, and then look at the really tricky ones, many of which will involve various degrees of infinity.
Model theory is mostly confined to first-order theories [Hart,WD]
     Full Idea: There is no developed methematics of models for second-order theories, so for the most part, model theory is about models for first-order theories.
     From: William D. Hart (The Evolution of Logic [2010], 9)
Models are ways the world might be from a first-order point of view [Hart,WD]
     Full Idea: Models are ways the world might be from a first-order point of view.
     From: William D. Hart (The Evolution of Logic [2010], 9)
5. Theory of Logic / K. Features of Logics / 6. Compactness
First-order logic is 'compact': consequences of a set are consequences of a finite subset [Hart,WD]
     Full Idea: First-order logic is 'compact', which means that any logical consequence of a set (finite or infinite) of first-order sentences is a logical consequence of a finite subset of those sentences.
     From: William D. Hart (The Evolution of Logic [2010], 3)
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / c. Berry's paradox
Berry's Paradox: we succeed in referring to a number, with a term which says we can't do that [Hart,WD]
     Full Idea: Berry's Paradox: by the least number principle 'the least number denoted by no description of fewer than 79 letters' exists, but we just referred to it using a description of 77 letters.
     From: William D. Hart (The Evolution of Logic [2010], 3)
     A reaction: I struggle with this. If I refer to 'an object to which no human being could possibly refer', have I just referred to something? Graham Priest likes this sort of idea.
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / c. Burali-Forti's paradox
The Burali-Forti paradox is a crisis for Cantor's ordinals [Hart,WD]
     Full Idea: The Burali-Forti Paradox was a crisis for Cantor's theory of ordinal numbers.
     From: William D. Hart (The Evolution of Logic [2010], 3)
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
The machinery used to solve the Liar can be rejigged to produce a new Liar [Hart,WD]
     Full Idea: In effect, the machinery introduced to solve the liar can always be rejigged to yield another version the liar.
     From: William D. Hart (The Evolution of Logic [2010], 4)
     A reaction: [He cites Hans Herzberger 1980-81] The machinery is Tarski's device of only talking about sentences of a language by using a 'metalanguage'.
6. Mathematics / A. Nature of Mathematics / 2. Geometry
Newton developed a kinematic approach to geometry [Newton, by Kitcher]
     Full Idea: The reduction of the problems of tangents, normals, curvature, maxima and minima were effected by Newton's kinematic approach to geometry.
     From: report of Isaac Newton (Principia Mathematica [1687]) by Philip Kitcher - The Nature of Mathematical Knowledge 10.1
     A reaction: This approach apparently contrasts with that of Leibniz.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
There are at least as many infinite cardinals as transfinite ordinals (because they will map) [Hart,WD]
     Full Idea: Since we can map the transfinite ordinals one-one into the infinite cardinals, there are at least as many infinite cardinals as transfinite ordinals.
     From: William D. Hart (The Evolution of Logic [2010], 1)
Von Neumann's ordinals generalise into the transfinite better, because Zermelo's ω is a singleton [Hart,WD]
     Full Idea: It is easier to generalize von Neumann's finite ordinals into the transfinite. All Zermelo's nonzero finite ordinals are singletons, but if ω were a singleton it is hard to see how if could fail to be the successor of its member and so not a limit.
     From: William D. Hart (The Evolution of Logic [2010], 3)
The less-than relation < well-orders, and partially orders, and totally orders the ordinal numbers [Hart,WD]
     Full Idea: We can show (using the axiom of choice) that the less-than relation, <, well-orders the ordinals, ...and that it partially orders the ordinals, ...and that it totally orders the ordinals.
     From: William D. Hart (The Evolution of Logic [2010], 1)
The axiom of infinity with separation gives a least limit ordinal ω [Hart,WD]
     Full Idea: The axiom of infinity with separation yields a least limit ordinal, which is called ω.
     From: William D. Hart (The Evolution of Logic [2010], 3)
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
19th century arithmetization of analysis isolated the real numbers from geometry [Hart,WD]
     Full Idea: The real numbers were not isolated from geometry until the arithmetization of analysis during the nineteenth century.
     From: William D. Hart (The Evolution of Logic [2010], 1)
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
We can establish truths about infinite numbers by means of induction [Hart,WD]
     Full Idea: Mathematical induction is a way to establish truths about the infinity of natural numbers by a finite proof.
     From: William D. Hart (The Evolution of Logic [2010], 5)
     A reaction: If there are truths about infinities, it is very tempting to infer that the infinities must therefore 'exist'. A nice, and large, question in philosophy is whether there can be truths without corresponding implications of existence.
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / l. Limits
Quantities and ratios which continually converge will eventually become equal [Newton]
     Full Idea: Quantities and the ratios of quantities, which in any finite time converge continually to equality, and, before the end of that time approach nearer to one another by any given difference become ultimately equal.
     From: Isaac Newton (Principia Mathematica [1687], Lemma 1), quoted by Philip Kitcher - The Nature of Mathematical Knowledge 10.2
     A reaction: Kitcher observes that, although Newton relies on infinitesimals, this quotation expresses something close to the later idea of a 'limit'.
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Euclid has a unique parallel, spherical geometry has none, and saddle geometry has several [Hart,WD]
     Full Idea: There is a familiar comparison between Euclid (unique parallel) and 'spherical' geometry (no parallel) and 'saddle' geometry (several parallels).
     From: William D. Hart (The Evolution of Logic [2010], 2)
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Mathematics makes existence claims, but philosophers usually say those are never analytic [Hart,WD]
     Full Idea: The thesis that no existence proposition is analytic is one of the few constants in philosophical consciences, but there are many existence claims in mathematics, such as the infinity of primes, five regular solids, and certain undecidable propositions.
     From: William D. Hart (The Evolution of Logic [2010], 2)
7. Existence / C. Structure of Existence / 8. Stuff / a. Pure stuff
Mass words do not have plurals, or numerical adjectives, or use 'fewer' [Hart,WD]
     Full Idea: Jespersen calls a noun a mass word when it has no plural, does not take numerical adjectives, and does not take 'fewer'.
     From: William D. Hart (The Evolution of Logic [2010], 3)
     A reaction: Jespersen was a great linguistics expert.
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
I suspect that each particle of bodies has attractive or repelling forces [Newton]
     Full Idea: Many things lead me to a suspicion that all phenomena may depend on certain forces by which the particles of bodies, by causes not yet known, either are impelled toward one another and cohere in regular figures,or are repelled from one another and recede.
     From: Isaac Newton (Principia Mathematica [1687], Pref)
     A reaction: For Newton, forces are not just abstractions that are convenient for mathematics, but realities which I would say are best described as 'powers'.
9. Objects / B. Unity of Objects / 1. Unifying an Object / b. Unifying aggregates
Particles mutually attract, and cohere at short distances [Newton]
     Full Idea: The particles of bodies attract one another at very small distances and cohere when they become contiguous.
     From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol)
     A reaction: This is the sort of account of unity which has to be given in the corpuscular view of things, once substantial forms are given up. What is missing here is the structure of the thing. A lump of dirt is as unified as a cat in this story.
9. Objects / C. Structure of Objects / 2. Hylomorphism / a. Hylomorphism
The unmoved mover and the soul show Aristotelian form as the ultimate mereological atom [Aristotle, by Koslicki]
     Full Idea: Aristotle's discussion of the unmoved mover and of the soul confirms the suspicion that form, when it is not thought of as the object represented in a definition, plays the role of the ultimate mereological atom within his system.
     From: report of Aristotle (works [c.330 BCE]) by Kathrin Koslicki - The Structure of Objects 6.6
     A reaction: Aristotle is concerned with which things are 'divisible', and he cites these two examples as indivisible, but they may be too unusual to offer an actual theory of how Aristotle builds up wholes from atoms. He denies atoms in matter.
9. Objects / C. Structure of Objects / 2. Hylomorphism / d. Form as unifier
The 'form' is the recipe for building wholes of a particular kind [Aristotle, by Koslicki]
     Full Idea: Thus in Aristotle we may think of an object's formal components as a sort of recipe for how to build wholes of that particular kind.
     From: report of Aristotle (works [c.330 BCE]) by Kathrin Koslicki - The Structure of Objects 7.2.5
     A reaction: In the elusive business of pinning down what Aristotle means by the crucial idea of 'form', this analogy strikes me as being quite illuminating. It would fit DNA in living things, and the design of an artifact.
9. Objects / C. Structure of Objects / 8. Parts of Objects / b. Sums of parts
The place of a thing is the sum of the places of its parts [Newton]
     Full Idea: The place of a whole is the same as the sum of the places of the parts, and is therefore internal and in the whole body.
     From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol)
     A reaction: Note that Newton is talking of the sums of places, and deriving them from the parts. This is the mereology of space.
11. Knowledge Aims / A. Knowledge / 1. Knowledge
For Aristotle, knowledge is of causes, and is theoretical, practical or productive [Aristotle, by Code]
     Full Idea: Aristotle thinks that in general we have knowledge or understanding when we grasp causes, and he distinguishes three fundamental types of knowledge - theoretical, practical and productive.
     From: report of Aristotle (works [c.330 BCE]) by Alan D. Code - Aristotle
     A reaction: Productive knowledge we tend to label as 'knowing how'. The centrality of causes for knowledge would get Aristotle nowadays labelled as a 'naturalist'. It is hard to disagree with his three types, though they may overlap.
12. Knowledge Sources / A. A Priori Knowledge / 1. Nature of the A Priori
The notion of a priori truth is absent in Aristotle [Aristotle, by Politis]
     Full Idea: The notion of a priori truth is conspicuously absent in Aristotle.
     From: report of Aristotle (works [c.330 BCE]) by Vassilis Politis - Aristotle and the Metaphysics 1.5
     A reaction: Cf. Idea 11240.
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
Fregean self-evidence is an intrinsic property of basic truths, rules and definitions [Hart,WD]
     Full Idea: The conception of Frege is that self-evidence is an intrinsic property of the basic truths, rules, and thoughts expressed by definitions.
     From: William D. Hart (The Evolution of Logic [2010], p.350)
     A reaction: The problem is always that what appears to be self-evident may turn out to be wrong. Presumably the effort of arriving at a definition ought to clarify and support the self-evident ingredient.
12. Knowledge Sources / A. A Priori Knowledge / 11. Denying the A Priori
The failure of key assumptions in geometry, mereology and set theory throw doubt on the a priori [Hart,WD]
     Full Idea: In the case of the parallels postulate, Euclid's fifth axiom (the whole is greater than the part), and comprehension, saying was believing for a while, but what was said was false. This should make a shrewd philosopher sceptical about a priori knowledge.
     From: William D. Hart (The Evolution of Logic [2010], 2)
     A reaction: Euclid's fifth is challenged by infinite numbers, and comprehension is challenged by Russell's paradox. I can't see a defender of the a priori being greatly worried about these cases. No one ever said we would be right - in doing arithmetic, for example.
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Aristotle is a rationalist, but reason is slowly acquired through perception and experience [Aristotle, by Frede,M]
     Full Idea: Aristotle is a rationalist …but reason for him is a disposition which we only acquire over time. Its acquisition is made possible primarily by perception and experience.
     From: report of Aristotle (works [c.330 BCE]) by Michael Frede - Aristotle's Rationalism p.173
     A reaction: I would describe this process as the gradual acquisition of the skill of objectivity, which needs the right knowledge and concepts to evaluate new experiences.
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
Aristotle wants to fit common intuitions, and therefore uses language as a guide [Aristotle, by Gill,ML]
     Full Idea: Since Aristotle generally prefers a metaphysical theory that accords with common intuitions, he frequently relies on facts about language to guide his metaphysical claims.
     From: report of Aristotle (works [c.330 BCE]) by Mary Louise Gill - Aristotle on Substance Ch.5
     A reaction: I approve of his procedure. I take intuition to be largely rational justifications too complex for us to enunciate fully, and language embodies folk intuitions in its concepts (especially if the concepts occur in many languages).
14. Science / B. Scientific Theories / 1. Scientific Theory
Plato says sciences are unified around Forms; Aristotle says they're unified around substance [Aristotle, by Moravcsik]
     Full Idea: Plato's unity of science principle states that all - legitimate - sciences are ultimately about the Forms. Aristotle's principle states that all sciences must be, ultimately, about substances, or aspects of substances.
     From: report of Aristotle (works [c.330 BCE], 1) by Julius Moravcsik - Aristotle on Adequate Explanations 1
14. Science / B. Scientific Theories / 6. Theory Holism
If you changed one of Newton's concepts you would destroy his whole system [Heisenberg on Newton]
     Full Idea: The connection between the different concept in [Newton's] system is so close that one could generally not change any one of the concepts without destroying the whole system
     From: comment on Isaac Newton (Principia Mathematica [1687]) by Werner Heisenberg - Physics and Philosophy 06
     A reaction: This holistic situation would seem to count against Newton's system, rather than for it. A good system should depend on nature, not on other parts of the system. Compare changing a rule of chess.
14. Science / C. Induction / 1. Induction
Science deduces propositions from phenomena, and generalises them by induction [Newton]
     Full Idea: In experimental philosophy, propositions are deduced from the phenomena and are made general by induction.
     From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol)
     A reaction: Sounds easy, but generalising by induction requires all sorts of assumptions about the stability of natural kinds. Since the kinds are only arrived at by induction, it is not easy to give a proper account here.
14. Science / D. Explanation / 1. Explanation / a. Explanation
Aristotelian explanations are facts, while modern explanations depend on human conceptions [Aristotle, by Politis]
     Full Idea: For Aristotle things which explain (the explanantia) are facts, which should not be associated with the modern view that says explanations are dependent on how we conceive and describe the world (where causes are independent of us).
     From: report of Aristotle (works [c.330 BCE]) by Vassilis Politis - Aristotle and the Metaphysics 2.1
     A reaction: There must be some room in modern thought for the Aristotelian view, if some sort of robust scientific realism is being maintained against the highly linguistic view of philosophy found in the twentieth century.
14. Science / D. Explanation / 2. Types of Explanation / a. Types of explanation
Aristotle's standard analysis of species and genus involves specifying things in terms of something more general [Aristotle, by Benardete,JA]
     Full Idea: The standard Aristotelian doctrine of species and genus in the theory of anything whatever involves specifying what the thing is in terms of something more general.
     From: report of Aristotle (works [c.330 BCE]) by José A. Benardete - Metaphysics: the logical approach Ch.10
14. Science / D. Explanation / 2. Types of Explanation / g. Causal explanations
We should admit only enough causes to explain a phenomenon, and no more [Newton]
     Full Idea: No more causes of natural things should be admitted than are both true and sufficient to explain the phenomena. …For nature does nothing in vain, …and nature is simple and does not indulge in the luxury of superfluous causes.
     From: Isaac Newton (Principia Mathematica [1687], Bk 3 Rule 1)
     A reaction: This emphasises that Ockham's Razor is a rule for physical explanation, and not just one for abstract theories. This is something like Van Fraassen's 'empirical adequacy'.
Natural effects of the same kind should be assumed to have the same causes [Newton]
     Full Idea: The causes assigned to natural effects of the same kind must be, so far as possible, the same. For example, the cause of respiration in man and beast.
     From: Isaac Newton (Principia Mathematica [1687], Bk 3 Rule 2)
     A reaction: It is impossible to rule out identical effects from differing causes, but explanation gets much more exciting (because wide-ranging) if Newton's rule is assumed.
14. Science / D. Explanation / 2. Types of Explanation / k. Explanations by essence
Aristotle regularly says that essential properties explain other significant properties [Aristotle, by Kung]
     Full Idea: The view that essential properties are those in virtue of which other significant properties of the subjects under investigation can be explained is encountered repeatedly in Aristotle's work.
     From: report of Aristotle (works [c.330 BCE]) by Joan Kung - Aristotle on Essence and Explanation IV
     A reaction: What does 'significant' mean here? I take it that the significant properties are the ones which explain the role, function and powers of the object.
From the phenomena, I can't deduce the reason for the properties of gravity [Newton]
     Full Idea: I have not as yet been able to deduce from the phenomena the reason for the properties of gravity.
     From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol)
     A reaction: I take it that giving the reasons for the properties of gravity would be an essentialist explanation. I am struck by the fact that the recent discovery of the Higgs Boson appears to give us a reason why things have mass (i.e. what causes mass).
18. Thought / A. Modes of Thought / 5. Rationality / c. Animal rationality
Aristotle and the Stoics denied rationality to animals, while Platonists affirmed it [Aristotle, by Sorabji]
     Full Idea: Aristotle, and also the Stoics, denied rationality to animals. …The Platonists, the Pythagoreans, and some more independent Aristotelians, did grant reason and intellect to animals.
     From: report of Aristotle (works [c.330 BCE]) by Richard Sorabji - Rationality 'Denial'
     A reaction: This is not the same as affirming or denying their consciousness. The debate depends on how rationality is conceived.
18. Thought / D. Concepts / 3. Ontology of Concepts / c. Fregean concepts
The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD]
     Full Idea: A Fregean concept is a function that assigns to each object a truth value. So instead of the colour green, the concept GREEN assigns truth to each green thing, but falsity to anything else.
     From: William D. Hart (The Evolution of Logic [2010], 2)
     A reaction: This would seem to immediately hit the renate/cordate problem, if there was a world in which all and only the green things happened to be square. How could Frege then distinguish the green from the square? Compare Idea 8245.
19. Language / E. Analyticity / 2. Analytic Truths
The notion of analytic truth is absent in Aristotle [Aristotle, by Politis]
     Full Idea: The notion of analytic truth is conspicuously absent in Aristotle.
     From: report of Aristotle (works [c.330 BCE]) by Vassilis Politis - Aristotle and the Metaphysics 1.5
     A reaction: Cf. Idea 11239.
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature
Aristotle never actually says that man is a rational animal [Aristotle, by Fogelin]
     Full Idea: To the best of my knowledge (and somewhat to my surprise), Aristotle never actually says that man is a rational animal; however, he all but says it.
     From: report of Aristotle (works [c.330 BCE]) by Robert Fogelin - Walking the Tightrope of Reason Ch.1
     A reaction: When I read this I thought that this database would prove Fogelin wrong, but it actually supports him, as I can't find it in Aristotle either. Descartes refers to it in Med.Two. In Idea 5133 Aristotle does say that man is a 'social being'. But 22586!
25. Social Practice / E. Policies / 5. Education / a. Aims of education
It is the mark of an educated mind to be able to entertain an idea without accepting it [Aristotle]
     Full Idea: It is the mark of an educated mind to be able to entertain an idea without accepting it.
     From: Aristotle (works [c.330 BCE])
     A reaction: The epigraph on a David Chalmers website. A wonderful remark, and it should be on the wall of every beginners' philosophy class. However, while it is in the spirit of Aristotle, it appears to be a misattribution with no ancient provenance.
25. Social Practice / E. Policies / 5. Education / b. Education principles
Aristotle said the educated were superior to the uneducated as the living are to the dead [Aristotle, by Diog. Laertius]
     Full Idea: Aristotle was asked how much educated men were superior to those uneducated; "As much," he said, "as the living are to the dead."
     From: report of Aristotle (works [c.330 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 05.1.11
26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature
There are potential infinities (never running out), but actual infinity is incoherent [Aristotle, by Friend]
     Full Idea: Aristotle developed his own distinction between potential infinity (never running out) and actual infinity (there being a collection of an actual infinite number of things, such as places, times, objects). He decided that actual infinity was incoherent.
     From: report of Aristotle (works [c.330 BCE]) by Michèle Friend - Introducing the Philosophy of Mathematics 1.3
     A reaction: Friend argues, plausibly, that this won't do, since potential infinity doesn't make much sense if there is not an actual infinity of things to supply the demand. It seems to just illustrate how boggling and uncongenial infinity was to Aristotle.
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / a. Greek matter
Aristotle's matter can become any other kind of matter [Aristotle, by Wiggins]
     Full Idea: Aristotle's conception of matter permits any kind of matter to become any other kind of matter.
     From: report of Aristotle (works [c.330 BCE]) by David Wiggins - Substance 4.11.2
     A reaction: This is obviously crucial background information when we read Aristotle on matter. Our 92+ elements, and fixed fundamental particles, gives a quite different picture. Aristotle would discuss form and matter quite differently now.
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / c. Ultimate substances
Newton's four fundamentals are: space, time, matter and force [Newton, by Russell]
     Full Idea: Newton works with four fundamental concepts: space, time, matter and force.
     From: report of Isaac Newton (Principia Mathematica [1687]) by Bertrand Russell - My Philosophical Development Ch.2
     A reaction: The ontological challenge is to reduce these in number, presumably. They are, notoriously, defined in terms of one another.
26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / a. Early Modern matter
Mass is central to matter [Newton, by Hart,WD]
     Full Idea: For Newton, mass is central to matter.
     From: report of Isaac Newton (Principia Mathematica [1687]) by William D. Hart - The Evolution of Logic 2
     A reaction: On reading this, I realise that this is the concept of matter I have grown up with, one which makes it very hard to grasp what the Greeks were thinking of when they referred to matter [hule].
26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / b. Corpuscles
An attraction of a body is the sum of the forces of their particles [Newton]
     Full Idea: The attractions of the bodies must be reckoned by assigning proper forces to their individual particles and then taking the sums of those forces.
     From: Isaac Newton (Principia Mathematica [1687], 1.II.Schol)
     A reaction: This is using the parts of bodies to give fundamental explanations, rather than invoking substantial forms. The parts need not be atoms.
26. Natural Theory / C. Causation / 1. Causation
Newtonian causation is changes of motion resulting from collisions [Newton, by Baron/Miller]
     Full Idea: In the Newtonian mechanistic theory of causation, ….something causes a result when it brings about a change of motion. …Causation is a matter of things bumping into one another.
     From: report of Isaac Newton (Principia Mathematica [1687]) by Baron,S/Miller,K - Intro to the Philosophy of Time 6.2.1
     A reaction: This seems to need impenetrability and elasticity as primitives (which is partly what Leibniz's monads are meant to explain). The authors observe that much causation is the result of existences and qualities, rather than motions.
26. Natural Theory / D. Laws of Nature / 6. Laws as Numerical
You have discovered that elliptical orbits result just from gravitation and planetary movement [Newton, by Leibniz]
     Full Idea: You have made the astonishing discovery that Kepler's ellipses result simply from the conception of attraction or gravitation and passage in a planet.
     From: report of Isaac Newton (Principia Mathematica [1687]) by Gottfried Leibniz - Letter to Newton 1693.03.07
     A reaction: I quote this to show that Newton made 'an astonishing discovery' of a connection in nature, and did not merely produce an equation which described a pattern of behaviour. The simple equation is the proof of the connection.
We have given up substantial forms, and now aim for mathematical laws [Newton]
     Full Idea: The moderns - rejecting substantial forms and occult qualities - have undertaken to reduce the phenomena of nature to mathematical laws.
     From: Isaac Newton (Principia Mathematica [1687], Preface)
     A reaction: This is the simplest statement of the apparent anti-Aristotelian revolution in the seventeenth century.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / c. Essence and laws
I am not saying gravity is essential to bodies [Newton]
     Full Idea: I am by no means asserting that gravity is essential to bodies.
     From: Isaac Newton (Principia Mathematica [1687], Bk 3 Rule 3)
     A reaction: Notice that in Idea 17009 he does not rule out gravity being essential to bodies. This is Newton's intellectual modesty (for which he is not famous).
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
Newton reclassified vertical motion as violent, and unconstrained horizontal motion as natural [Newton, by Harré]
     Full Idea: Following Kepler, Newton assumed a law of universal gravitation, thus reclassifying free fall as a violent motion and, with his First Law, fixing horizontal motion in the absence of constraints as natural
     From: report of Isaac Newton (Principia Mathematica [1687]) by Rom Harré - Laws of Nature 1
     A reaction: This is in opposition to the Aristotelian view, where the downward motion of physical objects is their natural motion.
27. Natural Reality / A. Classical Physics / 1. Mechanics / b. Laws of motion
Inertia rejects the Aristotelian idea of things having natural states, to which they return [Newton, by Alexander,P]
     Full Idea: Newton's principle of inertia implies a rejection of the Aristotelian idea of natural states to which things naturally return.
     From: report of Isaac Newton (Principia Mathematica [1687]) by Peter Alexander - Ideas, Qualities and Corpuscles 02.3
     A reaction: I think we can safely say that Aristotle was wrong about this. Aristotle made too much (such as the gravity acting on a thing) intrinsic to the bodies, when the whole context must be seen.
1: Bodies rest, or move in straight lines, unless acted on by forces [Newton]
     Full Idea: Law 1: Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by forces impressed.
     From: Isaac Newton (Principia Mathematica [1687], Axioms)
     A reaction: This is the new concept of inertia, which revolutionises the picture. Motion itself, which was a profound puzzle for the Greeks, ceases to be a problem by being axiomatised. It is now acceleration which is the the problem.
2: Change of motion is proportional to the force [Newton]
     Full Idea: Law 2: A change in motion is proportional to the motive force impressed and takes place along the straight line in which that force is impressed.
     From: Isaac Newton (Principia Mathematica [1687], Axioms)
     A reaction: This gives the equation 'force = mass x acceleration', where the mass is the constant needed for the equation of proportion. Effectively mass is just the value of a proportion.
3: All actions of bodies have an equal and opposite reaction [Newton]
     Full Idea: Law 3: To any action there is always an opposite and equal reaction; in other words, the action of two bodies upon each other are always equal and always opposite in direction.
     From: Isaac Newton (Principia Mathematica [1687], Axioms)
     A reaction: Is this still true if one body is dented by the impact and the other one isn't? What counts as a 'body'?
Newton's Third Law implies the conservation of momentum [Newton, by Papineau]
     Full Idea: Newton's Third Law implies the conservation of momentum, because 'action and reaction' are always equal.
     From: report of Isaac Newton (Principia Mathematica [1687]) by David Papineau - Thinking about Consciousness App 3
     A reaction: That is, the Third Law implies the First Law (which is the Law of Momentum).
27. Natural Reality / A. Classical Physics / 1. Mechanics / c. Forces
Newton's idea of force acting over a long distance was very strange [Heisenberg on Newton]
     Full Idea: Newton introduced a very new and strange hypothesis by assuming a force that acted over a long distance.
     From: comment on Isaac Newton (Principia Mathematica [1687]) by Werner Heisenberg - Physics and Philosophy 06
     A reaction: Why would a force that acted over a short distance be any less mysterious?
Newton introduced forces other than by contact [Newton, by Papineau]
     Full Idea: Newton allowed forces other than impact. All the earlier proponents of 'mechanical philosophy' took it as given that all physical action is by contact. ...He thought of 'impressed force' - disembodied entities acting from outside a body.
     From: report of Isaac Newton (Principia Mathematica [1687]) by David Papineau - Thinking about Consciousness App 3
     A reaction: This is 'action at a distance', which was as bewildering then as quantum theory is now. Newton had a divinity to impose laws of nature from the outside. In some ways we have moved back to the old view, with the actions of bosons and fields.
Newton's laws cover the effects of forces, but not their causes [Newton, by Papineau]
     Full Idea: Newton has a general law about the effects of his forces, ...but there is no corresponding general principle about the causes of such forces.
     From: report of Isaac Newton (Principia Mathematica [1687]) by David Papineau - Thinking about Consciousness App 3
     A reaction: I'm not sure that Einstein gives a cause of gravity either. This seems to be part of the scientific 'instrumentalist' view of nature, which is incredibly useful but very superficial.
Newton's forces were accused of being the scholastics' real qualities [Pasnau on Newton]
     Full Idea: Newton's reliance on the notion of force was widely criticised as marking in effect a return to real qualities.
     From: comment on Isaac Newton (Principia Mathematica [1687]) by Robert Pasnau - Metaphysical Themes 1274-1671 19.7
     A reaction: The objection is to forces that are separate from the bodies they act on. This is one of the reasons why modern metaphysics needs the concept of an intrinsic disposition or power, placing the forces in the stuff.
I am studying the quantities and mathematics of forces, not their species or qualities [Newton]
     Full Idea: I consider in this treatise not the species of forces and their physical qualities, but their quantities and mathematical proportions.
     From: Isaac Newton (Principia Mathematica [1687], 1.1.11 Sch)
     A reaction: Note that Newton is not denying that one might contemplate the species and qualities of forces, as I think Leibniz tried to do, thought he didn't cast any detailed light on them. It is the gap between science and metaphysics.
The aim is to discover forces from motions, and use forces to demonstrate other phenomena [Newton]
     Full Idea: The basic problem of philosophy seems to be to discover the forces of nature from the phenomena of motions and then to demonstrate the other phenomena from these forces.
     From: Isaac Newton (Principia Mathematica [1687], Pref 1st ed), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 4
     A reaction: This fits in with the description-of-regularity approach to laws which Newton had acquired from Galileo, rather than the essentialist attitude to forces of Leibniz, though Newton has smatterings of essentialism.
27. Natural Reality / A. Classical Physics / 1. Mechanics / d. Gravity
Newton showed that falling to earth and orbiting the sun are essentially the same [Newton, by Ellis]
     Full Idea: Newton showed that the apparently different kinds of processes of falling towards the earth and orbiting the sun are essentially the same.
     From: report of Isaac Newton (Principia Mathematica [1687]) by Brian Ellis - Scientific Essentialism 3.08
     A reaction: I quote this to illustrate Newton's permanent achievement in science, in the face of a tendency to say that he was 'outmoded' by the advent of General Relativity. Newton wasn't interestingly wrong. He was very very right.
27. Natural Reality / A. Classical Physics / 2. Thermodynamics / c. Conservation of energy
Early Newtonians could not formulate conservation of energy, having no concept of potential energy [Newton, by Papineau]
     Full Idea: A barrier to the formulation of an energy conservation principle by early Newtonians was their lack of a notion of potential energy.
     From: report of Isaac Newton (Principia Mathematica [1687]) by David Papineau - Thinking about Consciousness App 3 n5
     A reaction: Interestingly, the notions of potentiality and actuality were central to Aristotle, but Newtonians had just rejected all of that.
27. Natural Reality / C. Space / 4. Substantival Space
Absolute space is independent, homogeneous and immovable [Newton]
     Full Idea: Absolute space, of its own nature without reference to anything external, always remains homogeneous and immovable.
     From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol)
     A reaction: This would have to be a stipulation, rather than an assertion of fact, since whether space is 'immovable' is either incoherent or unknowable.
27. Natural Reality / D. Time / 1. Nature of Time / a. Absolute time
Newton needs intervals of time, to define velocity and acceleration [Newton, by Le Poidevin]
     Full Idea: Both Newton's First and Second Laws of motion make implicit reference to equal intervals of time. For a body is moving with constant velocity if it covers the same distance in a series of equal intervals (and similarly with acceleration).
     From: report of Isaac Newton (Principia Mathematica [1687]) by Robin Le Poidevin - Travels in Four Dimensions 01 'Time'
     A reaction: [Le Poidevin spells out the acceleration point] You can see why he needs time to be real, if measured chunks of it figure in his laws.
Newton thought his laws of motion needed absolute time [Newton, by Bardon]
     Full Idea: Newton's reason for embracing absolute space, time and motion was that he thought that universal laws of motions were describable only in such terms. Because actual motions are irregular, the time of universal laws of motion cannot depend on them.
     From: report of Isaac Newton (Principia Mathematica [1687]) by Adrian Bardon - Brief History of the Philosophy of Time 3 'Replacing'
     A reaction: I'm not sure of the Einsteinian account of the laws of motion.
Time exists independently, and flows uniformly [Newton]
     Full Idea: Absolute, true, and mathematical time, in and of itself and of its own nature, without reference to anything external, flows uniformly and by another name is called duration.
     From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol)
     A reaction: This invites the notorious question of, if time flows uniformly, how fast time flows. Maybe we should bite the bullet and say 'one second per second', or maybe we should say 'this fact is beyond our powers of comprehension'.
Absolute time, from its own nature, flows equably, without relation to anything external [Newton]
     Full Idea: Absolute, true, and mathematical time, of itself, and from its own nature, flows equably, without relation to anything external.
     From: Isaac Newton (Principia Mathematica [1687], I:Schol after defs), quoted by Craig Bourne - A Future for Presentism 5.1
     A reaction: I agree totally with this, and I don't care what any modern relativity theorists say. It think Shoemaker's argument gives wonderful support to Newton.
27. Natural Reality / D. Time / 2. Passage of Time / g. Time's arrow
Newtonian mechanics does not distinguish negative from positive values of time [Newton, by Coveney/Highfield]
     Full Idea: In Newton's laws of motion time is squared, so a negative value gives the same result as a positive value, which means Newtonian mechanics cannot distinguish between the two directions of time.
     From: report of Isaac Newton (Principia Mathematica [1687]) by P Coveney / R Highfield - The Arrow of Time 2 'anatomy'
     A reaction: Maybe Newton just forgot to mention that negative values were excluded. (Or was he unaware of the sequence of negative integers?). Too late now - he's done it.
27. Natural Reality / D. Time / 3. Parts of Time / d. Measuring time
If there is no uniform motion, we cannot exactly measure time [Newton]
     Full Idea: It is possible that there is no uniform motion by which time may have an exact measure. All motions can be accelerated and retarded, but the flow of absolute time cannot be changed.
     From: Isaac Newton (Principia Mathematica [1687], Def 8 Schol)
28. God / A. Divine Nature / 3. Divine Perfections
If a perfect being does not rule the cosmos, it is not God [Newton]
     Full Idea: A being, however perfect, without dominion is not the Lord God.
     From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol)
28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
The elegance of the solar system requires a powerful intellect as designer [Newton]
     Full Idea: This most elegant system of the sun, planets, and comets could not have arisen without the design and dominion of an intelligent and powerful being.
     From: Isaac Newton (Principia Mathematica [1687], Bk 3 Gen Schol)
29. Religion / A. Polytheistic Religion / 2. Greek Polytheism
The concepts of gods arose from observing the soul, and the cosmos [Aristotle, by Sext.Empiricus]
     Full Idea: Aristotle said that the conception of gods arose among mankind from two originating causes, namely from events which concern the soul and from celestial phenomena.
     From: report of Aristotle (works [c.330 BCE], Frag 10) by Sextus Empiricus - Against the Physicists (two books) I.20
     A reaction: The cosmos suggests order, and possible creation. What do events of the soul suggest? It doesn't seem to be its non-physical nature, because Aristotle is more of a functionalist. Puzzling. (It says later that gods are like the soul).