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All the ideas for 'On What Grounds What', 'Three Dialogues of Hylas and Philonous' and 'Nature and Meaning of Numbers'

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70 ideas

1. Philosophy / E. Nature of Metaphysics / 1. Nature of Metaphysics
Modern Quinean metaphysics is about what exists, but Aristotelian metaphysics asks about grounding [Schaffer,J]
     Full Idea: On the now dominant Quinean view, metaphysics is about what there is (such as properties, meanings and numbers). I will argue for the revival of a more traditional Aristotelian view, on which metaphysics is about what grounds what.
     From: Jonathan Schaffer (On What Grounds What [2009], Intro)
     A reaction: I find that an enormously helpful distinction, and support the Aristotelian view. Schaffer's general line is that what exists is fairly uncontroversial and dull, but the interesting truths about the world emerge when we grasp its structure.
1. Philosophy / E. Nature of Metaphysics / 3. Metaphysical Systems
If you tore the metaphysics out of philosophy, the whole enterprise would collapse [Schaffer,J]
     Full Idea: Traditional metaphysics is so tightly woven into the fabric of philosophy that it cannot be torn out without the whole tapestry unravelling.
     From: Jonathan Schaffer (On What Grounds What [2009], 2.3)
     A reaction: I often wonder why the opponents of metaphysics still continue to do philosophy. I don't see how you address questions of ethics, or philosophy of mathematics (etc) without coming up against highly general and abstract over-questions.
2. Reason / B. Laws of Thought / 6. Ockham's Razor
We should not multiply basic entities, but we can have as many derivative entities as we like [Schaffer,J]
     Full Idea: Occam's Razor should only be understood to concern substances: do not multiply basic entities without necessity. There is no problem with the multiplication of derivative entities - they are an 'ontological free lunch'.
     From: Jonathan Schaffer (On What Grounds What [2009], 2.1)
     A reaction: The phrase 'ontological free lunch' comes from Armstrong. This is probably what Occam meant. A few extra specks of dust, or even a few more numbers (thank you, Cantor!) don't seem to challenge the principle.
2. Reason / D. Definition / 9. Recursive Definition
Dedekind proved definition by recursion, and thus proved the basic laws of arithmetic [Dedekind, by Potter]
     Full Idea: Dedkind gave a rigorous proof of the principle of definition by recursion, permitting recursive definitions of addition and multiplication, and hence proofs of the familiar arithmetical laws.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 13 'Deriv'
4. Formal Logic / F. Set Theory ST / 3. Types of Set / d. Infinite Sets
An infinite set maps into its own proper subset [Dedekind, by Reck/Price]
     Full Idea: A set is 'Dedekind-infinite' iff there exists a one-to-one function that maps a set into a proper subset of itself.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888], §64) by E Reck / M Price - Structures and Structuralism in Phil of Maths n 7
     A reaction: Sounds as if it is only infinite if it is contradictory, or doesn't know how big it is!
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
We have the idea of self, and an idea of that idea, and so on, so infinite ideas are available [Dedekind, by Potter]
     Full Idea: Dedekind had an interesting proof of the Axiom of Infinity. He held that I have an a priori grasp of the idea of my self, and that every idea I can form the idea of that idea. Hence there are infinitely many objects available to me a priori.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888], no. 66) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 12 'Numb'
     A reaction: Who said that Descartes' Cogito was of no use? Frege endorsed this, as long as the ideas are objective and not subjective.
4. Formal Logic / G. Formal Mereology / 1. Mereology
Dedekind originally thought more in terms of mereology than of sets [Dedekind, by Potter]
     Full Idea: Dedekind plainly had fusions, not collections, in mind when he avoided the empty set and used the same symbol for membership and inclusion - two tell-tale signs of a mereological conception.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888], 2-3) by Michael Potter - Set Theory and Its Philosophy 02.1
     A reaction: Potter suggests that mathematicians were torn between mereology and sets, and eventually opted whole-heartedly for sets. Maybe this is only because set theory was axiomatised by Zermelo some years before Lezniewski got to mereology.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / a. Numbers
Numbers are free creations of the human mind, to understand differences [Dedekind]
     Full Idea: Numbers are free creations of the human mind; they serve as a means of apprehending more easily and more sharply the difference of things.
     From: Richard Dedekind (Nature and Meaning of Numbers [1888], Pref)
     A reaction: Does this fit real numbers and complex numbers, as well as natural numbers? Frege was concerned by the lack of objectivity in this sort of view. What sort of arithmetic might the Martians have created? Numbers register sameness too.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers
Dedekind defined the integers, rationals and reals in terms of just the natural numbers [Dedekind, by George/Velleman]
     Full Idea: It was primarily Dedekind's accomplishment to define the integers, rationals and reals, taking only the system of natural numbers for granted.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by A.George / D.J.Velleman - Philosophies of Mathematics Intro
Ordinals can define cardinals, as the smallest ordinal that maps the set [Dedekind, by Heck]
     Full Idea: Dedekind and Cantor said the cardinals may be defined in terms of the ordinals: The cardinal number of a set S is the least ordinal onto whose predecessors the members of S can be mapped one-one.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by Richard G. Heck - Cardinality, Counting and Equinumerosity 5
Order, not quantity, is central to defining numbers [Dedekind, by Monk]
     Full Idea: Dedekind said that the notion of order, rather than that of quantity, is the central notion in the definition of number.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by Ray Monk - Bertrand Russell: Spirit of Solitude Ch.4
     A reaction: Compare Aristotle's nice question in Idea 646. My intuition is that quantity comes first, because I'm not sure HOW you could count, if you didn't think you were changing the quantity each time. Why does counting go in THAT particular order? Cf. Idea 8661.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
Dedekind's ordinals are just members of any progression whatever [Dedekind, by Russell]
     Full Idea: Dedekind's ordinals are not essentially either ordinals or cardinals, but the members of any progression whatever.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by Bertrand Russell - The Principles of Mathematics §243
     A reaction: This is part of Russell's objection to Dedekind's structuralism. The question is always why these beautiful structures should actually be considered as numbers. I say, unlike Russell, that the connection to counting is crucial.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / i. Reals from cuts
Dedekind's axiom that his Cut must be filled has the advantages of theft over honest toil [Dedekind, by Russell]
     Full Idea: Dedekind set up the axiom that the gap in his 'cut' must always be filled …The method of 'postulating' what we want has many advantages; they are the same as the advantages of theft over honest toil. Let us leave them to others.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by Bertrand Russell - Introduction to Mathematical Philosophy VII
     A reaction: This remark of Russell's is famous, and much quoted in other contexts, but I have seen the modern comment that it is grossly unfair to Dedekind.
Dedekind says each cut matches a real; logicists say the cuts are the reals [Dedekind, by Bostock]
     Full Idea: One view, favoured by Dedekind, is that the cut postulates a real number for each cut in the rationals; it does not identify real numbers with cuts. ....A view favoured by later logicists is simply to identify a real number with a cut.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by David Bostock - Philosophy of Mathematics 4.4
     A reaction: Dedekind is the patriarch of structuralism about mathematics, so he has little interest in the existenc of 'objects'.
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / c. Counting procedure
In counting we see the human ability to relate, correspond and represent [Dedekind]
     Full Idea: If we scrutinize closely what is done in counting an aggregate of things, we see the ability of the mind to relate things to things, to let a thing correspond to a thing, or to represent a thing by a thing, without which no thinking is possible.
     From: Richard Dedekind (Nature and Meaning of Numbers [1888], Pref)
     A reaction: I don't suppose it occurred to Dedekind that he was reasserting Hume's observation about the fundamental psychology of thought. Is the origin of our numerical ability of philosophical interest?
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / b. Mark of the infinite
A system S is said to be infinite when it is similar to a proper part of itself [Dedekind]
     Full Idea: A system S is said to be infinite when it is similar to a proper part of itself.
     From: Richard Dedekind (Nature and Meaning of Numbers [1888], V.64)
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
Dedekind gives a base number which isn't a successor, then adds successors and induction [Dedekind, by Hart,WD]
     Full Idea: Dedekind's natural numbers: an object is in a set (0 is a number), a function sends the set one-one into itself (numbers have unique successors), the object isn't a value of the function (it isn't a successor), plus induction.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by William D. Hart - The Evolution of Logic 5
     A reaction: Hart notes that since this refers to sets of individuals, it is a second-order account of numbers, what we now call 'Second-Order Peano Arithmetic'.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
Zero is a member, and all successors; numbers are the intersection of sets satisfying this [Dedekind, by Bostock]
     Full Idea: Dedekind's idea is that the set of natural numbers has zero as a member, and also has as a member the successor of each of its members, and it is the smallest set satisfying this condition. It is the intersection of all sets satisfying the condition.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by David Bostock - Philosophy of Mathematics 4.4
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
Categoricity implies that Dedekind has characterised the numbers, because it has one domain [Rumfitt on Dedekind]
     Full Idea: It is Dedekind's categoricity result that convinces most of us that he has articulated our implicit conception of the natural numbers, since it entitles us to speak of 'the' domain (in the singular, up to isomorphism) of natural numbers.
     From: comment on Richard Dedekind (Nature and Meaning of Numbers [1888]) by Ian Rumfitt - The Boundary Stones of Thought 9.1
     A reaction: The main rival is set theory, but that has an endlessly expanding domain. He points out that Dedekind needs second-order logic to achieve categoricity. Rumfitt says one could also add to the 1st-order version that successor is an ancestral relation.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
Induction is proved in Dedekind, an axiom in Peano; the latter seems simpler and clearer [Dedekind, by Russell]
     Full Idea: Dedekind proves mathematical induction, while Peano regards it as an axiom, ...and Peano's method has the advantage of simplicity, and a clearer separation between the particular and the general propositions of arithmetic.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by Bertrand Russell - The Principles of Mathematics §241
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Dedekind originated the structuralist conception of mathematics [Dedekind, by MacBride]
     Full Idea: Dedekind is the philosopher-mathematician with whom the structuralist conception originates.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888], §3 n13) by Fraser MacBride - Structuralism Reconsidered
     A reaction: Hellman says the idea grew naturally out of modern mathematics, and cites Hilbert's belief that furniture would do as mathematical objects.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / b. Varieties of structuralism
Dedekindian abstraction talks of 'positions', where Cantorian abstraction talks of similar objects [Dedekind, by Fine,K]
     Full Idea: Dedekindian abstraction says mathematical objects are 'positions' in a model, while Cantorian abstraction says they are the result of abstracting on structurally similar objects.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by Kit Fine - Cantorian Abstraction: Recon. and Defence §6
     A reaction: The key debate among structuralists seems to be whether or not they are committed to 'objects'. Fine rejects the 'austere' version, which says that objects have no properties. Either version of structuralism can have abstraction as its basis.
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / a. For mathematical platonism
If 'there are red roses' implies 'there are roses', then 'there are prime numbers' implies 'there are numbers' [Schaffer,J]
     Full Idea: We can automatically infer 'there are roses' from 'there are red roses' (with no shift in the meaning of 'roses'). Likewise one can automatically infer 'there are numbers' from 'there are prime numbers'.
     From: Jonathan Schaffer (On What Grounds What [2009], 2.1)
     A reaction: He similarly observes that the atheist's 'God is a fictional character' implies 'there are fictional characters'. Schaffer is not committing to a strong platonism with his claim - merely that the existence of numbers is hardly worth disputing.
7. Existence / A. Nature of Existence / 5. Reason for Existence
I do not believe in the existence of anything, if I see no reason to believe it [Berkeley]
     Full Idea: It is to me a sufficient reason not to believe the existence of anything, if I see no reason for believing it.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.205)
     A reaction: This may just be a reasonable application of Ockham's Razor, but I fear that Berkeley painted himself into corner by demanding too many 'reasons' for everything.
7. Existence / A. Nature of Existence / 6. Criterion for Existence
I know that nothing inconsistent can exist [Berkeley]
     Full Idea: I know that nothing inconsistent can exist.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.224)
     A reaction: Fine, but the problem is to assess with confidence what is inconsistent. Human imagination seems to be the test for existence. But what else can we do?
7. Existence / C. Structure of Existence / 1. Grounding / a. Nature of grounding
Grounding is unanalysable and primitive, and is the basic structuring concept in metaphysics [Schaffer,J]
     Full Idea: Grounding should be taken as primitive, as per the neo-Aristotelian approach. Grounding is an unanalyzable but needed notion - it is the primitive structuring conception of metaphysics.
     From: Jonathan Schaffer (On What Grounds What [2009], 2.2)
     A reaction: [he cites K.Fine 1991] I find that this simple claim clarifies the discussions of Kit Fine, where you are not always quite sure what the game is. I agree fully with it. It makes metaphysics interesting, where cataloguing entities is boring.
7. Existence / C. Structure of Existence / 5. Supervenience / a. Nature of supervenience
Supervenience is just modal correlation [Schaffer,J]
     Full Idea: Supervenience is mere modal correlation.
     From: Jonathan Schaffer (On What Grounds What [2009], 2.2)
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
The cosmos is the only fundamental entity, from which all else exists by abstraction [Schaffer,J]
     Full Idea: My preferred view is that there is only one fundamental entity - the whole concrete cosmos - from which all else exists by abstraction.
     From: Jonathan Schaffer (On What Grounds What [2009], 2.1)
     A reaction: This looks to me like weak anti-realism - that there are no natural 'joints' in nature - but I don't think Schaffer intends that. I take the joints to be fundamentals, which necessitates that the cosmos has parts. His 'abstraction' is clearly a process.
7. Existence / E. Categories / 4. Category Realism
Maybe categories are just the different ways that things depend on basic substances [Schaffer,J]
     Full Idea: Maybe the categories are determined by the different grounding relations, ..so that categories just are the ways things depend on substances. ...Categories are places in the dependence ordering.
     From: Jonathan Schaffer (On What Grounds What [2009], 1.3)
9. Objects / A. Existence of Objects / 3. Objects in Thought
A thing is completely determined by all that can be thought concerning it [Dedekind]
     Full Idea: A thing (an object of our thought) is completely determined by all that can be affirmed or thought concerning it.
     From: Richard Dedekind (Nature and Meaning of Numbers [1888], I.1)
     A reaction: How could you justify this as an observation? Why can't there be unthinkable things (even by God)? Presumably Dedekind is offering a stipulative definition, but we may then be confusing epistemology with ontology.
9. Objects / B. Unity of Objects / 2. Substance / d. Substance defined
There is no other substance, in a strict sense, than spirit [Berkeley]
     Full Idea: There is no other substance, in a strict sense, than spirit.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.257)
     A reaction: A nice clear statement of idealism. Why is he so confident of making this assertion. Note the addition, though, of 'in a strict' sense. He is presenting an epistemological claim as if it was an ontological one.
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
There exist heaps with no integral unity, so we should accept arbitrary composites in the same way [Schaffer,J]
     Full Idea: I am happy to accept universal composition, on the grounds that there are heaps, piles etc with no integral unity, and that arbitrary composites are no less unified than heaps.
     From: Jonathan Schaffer (On What Grounds What [2009], 2.1 n11)
     A reaction: The metaphysical focus is then placed on what constitutes 'integral unity', which is precisely the question which most interested Aristotle. Clearly if there is nothing more to an entity than its components, scattering them isn't destruction.
The notion of 'grounding' can explain integrated wholes in a way that mere aggregates can't [Schaffer,J]
     Full Idea: The notion of grounding my capture a crucial mereological distinction (missing from classical mereology) between an integrated whole with genuine unity, and a mere aggregate. x is an integrated whole if it grounds its proper parts.
     From: Jonathan Schaffer (On What Grounds What [2009], 3.1)
     A reaction: That gives a nice theoretical notion, but if you remove each of the proper parts, does x remain? Is it a bare particular? I take it that it will have to be an abstract principle, the one Aristotle was aiming at with his notion of 'form'. Schaffer agrees.
10. Modality / A. Necessity / 10. Impossibility
A thing is shown to be impossible if a contradiction is demonstrated within its definition [Berkeley]
     Full Idea: A thing is shown to be impossible when a repugnancy is demonstrated between the ideas comprehended in its definition.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.214)
     A reaction: The problem is always that imagination is needed to see the 'repugnancy', and that is relative and limited.
10. Modality / E. Possible worlds / 1. Possible Worlds / b. Impossible worlds
Belief in impossible worlds may require dialetheism [Schaffer,J]
     Full Idea: One motivation for dialetheism is the view that there are impossible worlds.
     From: Jonathan Schaffer (On What Grounds What [2009], 2.3)
11. Knowledge Aims / B. Certain Knowledge / 2. Common Sense Certainty
'Moorean certainties' are more credible than any sceptical argument [Schaffer,J]
     Full Idea: A 'Moorean certainty' is when something is more credible than any philosopher's argument to the contrary.
     From: Jonathan Schaffer (On What Grounds What [2009], 2.1)
     A reaction: The reference is to G.E. Moore's famous claim that the existence of his hand is more certain than standard sceptical arguments. It sounds empiricist, but they might be parallel rational truths, of basic logic or arithmetic.
11. Knowledge Aims / C. Knowing Reality / 1. Perceptual Realism / a. Naďve realism
Since our ideas vary when the real things are said to be unchanged, they cannot be true copies [Berkeley]
     Full Idea: As our ideas are perpetually varied, without any change in the supposed real things, it necessarily follows that they cannot all be true copies of them.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.239)
     A reaction: This seems a good objection to any direct or naďve realist view. Colours get darker as the sun goes down, and objects become blurred as they recede into the distance.
11. Knowledge Aims / C. Knowing Reality / 1. Perceptual Realism / b. Direct realism
If existence is perceived directly, by which sense; if indirectly, how is it inferred from direct perception? [Berkeley]
     Full Idea: Either you perceive the being of matter immediately, or mediately; if immediately, pray inform me by which of the senses you perceive it; if mediately, let me know by what reasonings it is inferred from those things which you perceive immediately.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.208)
     A reaction: A problem for strong empiricists, and he is right that existence can't be directly perceived, but it seems a good explanation (for which some reason can be shown), and supports a more rationalist view.
11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism
Sensible objects are just sets of sensible qualities [Berkeley]
     Full Idea: Sensible things are nothing else but so many sensible qualities.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.154)
     A reaction: As it stands this is phenomenalism, but Berkeley eventually votes for idealism. He should acknowledge possible sensations which aren't actually experienced.
Berkeley did not deny material things; he merely said they must be defined through sensations [Berkeley, by Ayer]
     Full Idea: Berkeley did not (as we are commonly told) deny the reality of material things. ..What Berkeley discovered was that material things must be defined in terms of sense-contents.
     From: report of George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by A.J. Ayer - Language,Truth and Logic Ch.2
     A reaction: This seems to be a rather debatable attempt to claim that Berkeley was a phenomenalist (like Ayer), rather than an idealist. Try ideas 3942, 3944, 3945, 3957, 3959 in this database.
Berkeley needed a phenomenalist account of the self, as well as of material things [Ayer on Berkeley]
     Full Idea: The considerations which make it necessary, as Berkeley saw, to give a phenomenalist account of material things, make it necessary also, as Berkeley did not see, to give a phenomenalist account of the self.
     From: comment on George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by A.J. Ayer - Language,Truth and Logic Ch.7
     A reaction: Phenomenalism involves 'possible' experiences as well as actual ones. That could add up to quite a rich and stable account of the self, as opposed to Hume's notorious introspection, which only saw an actual shifting 'bundle' of experience.
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / c. Empirical idealism
'To be is to be perceived' is a simple confusion of experience with its objects [Russell on Berkeley]
     Full Idea: Berkeley thinks 'to be is to be perceived', and only God provides continuity. He has simply confused the experience of perception with the thing being perceived. Ideas have content.
     From: comment on George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by Bertrand Russell - Problems of Philosophy
For Berkelely, reality is ideas and a community of minds, including God's [Berkeley, by Grayling]
     Full Idea: Berkeley's thesis is that reality ultimately consists of a community of minds and their ideas; one of the minds (God) is infinite, and causes most of the ideas.
     From: report of George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by A.C. Grayling - Russell Ch.2
     A reaction: I think Russell nicely pinpoints what is wrong with Berekely, which is that he confuses ideas with their contents. If I think about my garden, the garden is real (probably), which is the content, and they idea is just a way of thinking.
Time is measured by the succession of ideas in our minds [Berkeley]
     Full Idea: Time is measured by the succession of ideas in our minds.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.172)
     A reaction: But we distinguish between subjective time (which flies when you are having fun), and objective time, judged from observation of clocks and nature.
There is no such thing as 'material substance' [Berkeley]
     Full Idea: That there is no such thing as what philosophers call 'material substance', I am seriously persuaded.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.150)
     A reaction: I'm sorry, but I can't do with this. It confuses epistemology with ontology. Ontology is a matter of judgement; epistemology is the evidence on which we base it. We know sensations; personally I judge that there are material substances. What about you?
I conceive a tree in my mind, but I cannot prove that its existence can be conceived outside a mind [Berkeley]
     Full Idea: I may conceive in my own thoughts the idea of a tree, but that is all. And this is far from proving that I can conceive it existing out of the minds of all spirits.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.184)
     A reaction: If Berkeley has based a world view on this point, then his mistake is to require a 'proof'. Aristotle explained why you can't prove everything (not to mention Gödel).
There is nothing in nature which needs the concept of matter to explain it [Berkeley]
     Full Idea: I challenge you to show me that thing in nature which needs matter to explain or account for it.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.212)
     A reaction: I disagree. Physics is a good theory for explaining why we have perceptions. Failing that there is not even a glimmer of an explanation of our experiences.
Perceptions are ideas, and ideas exist in the mind, so objects only exist in the mind [Berkeley]
     Full Idea: Wood, fire, water, flesh, iron, are things that I know, and only known because I perceive them by my senses; these are immediately perceived, and so are ideas; ideas cannot exist without the mind; their existence consists therefore in being perceived.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.220)
     A reaction: This makes no distinction between an idea and its content. Berkeley fails to grasp the weird concept of intentionality. Trees aren't in my head, just because I think about them!
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / c. Primary qualities
Primary qualities (such as shape, solidity, mass) are held to really exist, unlike secondary qualities [Berkeley]
     Full Idea: Sensible qualities are by philosophers divided into primary and secondary; the former are extension, figure, solidity, gravity, motion and rest, which exist really in bodies.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.169)
     A reaction: A crucial distinction, which anti-realists such as Berkeley end up denying. I think it is a good distinction, and philosophers should fight to preserve it.
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / e. Primary/secondary critique
A mite would see its own foot as large, though we would see it as tiny [Berkeley]
     Full Idea: A mite must be supposed to see his own foot as a body of some considerable dimension, though they appear to you scarcely discernible.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.170)
     A reaction: Berkeley is confused. Hot is secondary, but temperature is primary. Bigness is secondary, size primay. Midgets and tall people don't disagree over the size of a table.
The apparent size of an object varies with its distance away, so that can't be a property of the object [Berkeley]
     Full Idea: As we approach to or recede from an object, the visible extension varies, being at one distance ten or a hundred times greater than at another; doth it not follow that it is not really inherent in the object?
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.171)
     A reaction: Berkeley is confused, because he is too literally empirical. Qualities are not self-evidently primary or secondary, but are judged so after comparisons (e.g. with testimony, or with the other senses).
'Solidity' is either not a sensible quality at all, or it is clearly relative to our senses [Berkeley]
     Full Idea: By 'solidity' either you do not mean any sensible quality, and so it is beside our enquiry; or if you do, it must be hardness or resistance, which are plainly relative to our senses.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.173)
     A reaction: Berkeley fails to recognise that a quality can have primary and secondary aspects (hot/high temperature). He is right that primary qualities are not directly perceived. They are judgements.
Distance is not directly perceived by sight [Berkeley]
     Full Idea: Distance is not properly and immediately perceived by sight.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.186)
     A reaction: Interestingly, if secondary qualities are not strictly perceptions of the object, and primary qualities are not directly perceived, then we don't seem to perceive anything at all. Perhaps we should drop the concept of 'perception'?
12. Knowledge Sources / B. Perception / 3. Representation
Immediate objects of perception, which some treat as appearances, I treat as the real things themselves [Berkeley]
     Full Idea: Those immediate objects of perception, which, according to you, are only appearances of things, I take to be the real things themselves.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.237)
     A reaction: If that is a judgement, which it seems to be, it is a strange one. Realists offer a much better explanation of perceptions.
12. Knowledge Sources / D. Empiricism / 1. Empiricism
Real things and imaginary or dreamed things differ because the latter are much fainter [Berkeley]
     Full Idea: The difference between real things, and chimeras formed by the imagination, or the visions of a dream, is that the latter are faint and indistinct.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.225)
     A reaction: In Hume this becomes 'impressions' and 'ideas'. It does raise the question of WHY some ideas are not as faint as others.
12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism
Geometry is originally perceived by senses, and so is not purely intellectual [Berkeley]
     Full Idea: Figures and extension, being originally perceived by sense, do not belong to pure intellect.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.176)
     A reaction: Is the square root of 169 less 'pure' in my mind if I learn it from laying out bricks instead of by thinking about numbers? Confusion of how you learn with what you learn?
13. Knowledge Criteria / D. Scepticism / 3. Illusion Scepticism
It is possible that we could perceive everything as we do now, but nothing actually existed. [Berkeley]
     Full Idea: We might perceive all things just as we do now, though there was no matter in the world.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.209)
     A reaction: An old Greek argument. Now we have an explanation of experience, but we wouldn't if nothing existed. Which doesn't prove that anything exists. Is some explanation always preferable to none? Cf. religion.
13. Knowledge Criteria / E. Relativism / 3. Subjectivism
A hot hand and a cold hand will have different experiences in the same tepid water [Berkeley]
     Full Idea: Suppose now one of your hands hot, and the other cold, and that they are both at once put into the same vessel of water, in an intermediate state; will not the water seem cold to one hand, and warm to the other?
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], I p.158)
     A reaction: A nice clear example of how some relativism must be acknowledged. It feels hot, but what is its temperature in degrees C?
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / c. Knowing other minds
Experience tells me that other minds exist independently from my own [Berkeley]
     Full Idea: It is plain that other minds have an existence exterior to my mind, since I find them by experience to be independent of it.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.220)
     A reaction: This is a surprising claim from Berkeley. If trees only exist through their experience in my mind, why don't other minds exist in the same way?
17. Mind and Body / E. Mind as Physical / 5. Causal Argument
How can that which is unthinking be a cause of thought? [Berkeley]
     Full Idea: How can that which is unthinking be a cause of thought?
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.203)
     A reaction: Presumably, though, he thinks that thought can cause 'that which is unthinking' to move'. He likes one half of the interaction problem (which supports dualism), but avoids the other half.
18. Thought / C. Content / 2. Ideas
Berkeley probably used 'idea' to mean both the act of apprehension and the thing apprehended [Russell on Berkeley]
     Full Idea: Berkeley seems to have confused the colour of the thing apprehended with the act of apprehension; probably either of these would have been called an 'idea' be Berkeley.
     From: comment on George Berkeley (Three Dialogues of Hylas and Philonous [1713]) by Bertrand Russell - Problems of Philosophy
     A reaction: If we are saying that Berkeley's error was entirely verbal, there is a chicken-and-egg problem. He was an idealist, so he wouldn't have thought that there were two separate concepts behind the word 'idea'. Russell merely asserts that there are.
18. Thought / E. Abstraction / 3. Abstracta by Ignoring
Dedekind said numbers were abstracted from systems of objects, leaving only their position [Dedekind, by Dummett]
     Full Idea: By applying the operation of abstraction to a system of objects isomorphic to the natural numbers, Dedekind believed that we obtained the abstract system of natural numbers, each member having only properties consequent upon its position.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by Michael Dummett - The Philosophy of Mathematics
     A reaction: Dummett is scornful of the abstractionism. He cites Benacerraf as a modern non-abstractionist follower of Dedekind's view. There seems to be a suspicion of circularity in it. How many objects will you abstract from to get seven?
We derive the natural numbers, by neglecting everything of a system except distinctness and order [Dedekind]
     Full Idea: If in an infinite system, set in order, we neglect the special character of the elements, simply retaining their distinguishability and their order-relations to one another, then the elements are the natural numbers, created by the human mind.
     From: Richard Dedekind (Nature and Meaning of Numbers [1888], VI.73)
     A reaction: [compressed] This is the classic abstractionist view of the origin of number, but with the added feature that the order is first imposed, so that ordinals remain after the abstraction. This, of course, sounds a bit circular, as well as subjective.
18. Thought / E. Abstraction / 8. Abstractionism Critique
Dedekind has a conception of abstraction which is not psychologistic [Dedekind, by Tait]
     Full Idea: Dedekind's conception is psychologistic only if that is the only way to understand the abstraction that is involved, which it is not.
     From: report of Richard Dedekind (Nature and Meaning of Numbers [1888]) by William W. Tait - Frege versus Cantor and Dedekind IV
     A reaction: This is a very important suggestion, implying that we can retain some notion of abstractionism, while jettisoning the hated subjective character of private psychologism, which seems to undermine truth and logic.
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / a. Preconditions for ethics
Immorality is not in the action, but in the deviation of the will from moral law [Berkeley]
     Full Idea: Sin or moral turpitude doth not consist in the outward physical action or motion, but in the internal deviation of the will from the laws of reason and religion.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.227)
     A reaction: A Kantian view (that the only good thing is a good will). It is a very empiricist (and anti-Greek) view to deny that actions have any intrinsic value.
28. God / B. Proving God / 1. Proof of God
There must be a God, because all sensible things must be perceived by him [Berkeley]
     Full Idea: I immediately and necessarily conclude the being of a God, because all sensible things must be perceived by him.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.198)
     A reaction: Daft. This contradicts Berkeley's whole empiricist position, that existence depends on known experience. Who knows whether God is thinking about trees?
There must be a God, because I and my ideas are not independent [Berkeley]
     Full Idea: From the dependency I find in myself and my ideas, I do by an act of reason necessarily infer the existence of a God.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.222)
     A reaction: No. Hume answered this, by showing how big abstract ideas are built up from experience. This is a future bishop's wish-fulfilment.
28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
It has been proved that creation is the workmanship of God, from its beauty and usefulness [Berkeley]
     Full Idea: Divines and philosophers have proved beyond all controversy, from the beauty and usefulness of the several parts of creation, that it was the workmanship of God.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], II p.198)
     A reaction: Not convincing. Beauty is probably a sublimation of sexual desire (or an echo of the human mind in the external world, in music), and utility is relative to homo sapiens, I presume.
29. Religion / D. Religious Issues / 3. Problem of Evil / b. Human Evil
People are responsible because they have limited power, though this ultimately derives from God [Berkeley]
     Full Idea: Thinking rational beings, in the production of motions, have the use of limited powers, ultimately derived from God, but immediately under the direction of their own wills, which is sufficient to entitle them to all the guilt of their own actions.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.228)
     A reaction: An episcopal evasion. A classic attempt to have cake and eat it. Either God is in charge or he isn't.
29. Religion / D. Religious Issues / 3. Problem of Evil / d. Natural Evil
If sin is not just physical, we don't consider God the origin of sin because he causes physical events [Berkeley]
     Full Idea: If sin doth not consist of purely physical actions, the making God a cause of all such actions, is not making him the author of sin.
     From: George Berkeley (Three Dialogues of Hylas and Philonous [1713], III p.227)
     A reaction: An equivocation. If responsibility resides in consciousness, God is presumably conscious, and we can judge the events he causes.