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All the ideas for 'On the Question of Absolute Undecidability', 'Modern Philosophy:introduction and survey' and 'The Metaphysics of Modality'

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60 ideas

1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / c. Philosophy as generalisation
Philosophy aims to provide a theory of everything [Scruton]
     Full Idea: Philosophy studies everything: it tries to provide a theory of the whole of things.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 1.2)
     A reaction: Good, but you can't avoid value-judgements about which things are important; philosophers place more value on moral theories than on theories about glacier movement. There is a tension in philosophy between human and eternal concerns.
1. Philosophy / E. Nature of Metaphysics / 2. Possibility of Metaphysics
There must be a plausible epistemological theory alongside any metaphysical theory [Forbes,G]
     Full Idea: No metaphysical account which renders it impossible to give a plausible epistemological theory is to be countenanced.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 9.1)
     A reaction: It is hard to object to this principle, though we certainly don't want to go verificationist, and thus rule out speculations about metaphysics which are beyond any possible knowledge. Some have tried to prove that something must exist (e.g. Jacquette).
1. Philosophy / F. Analytic Philosophy / 3. Analysis of Preconditions
If p entails q, then p is sufficient for q, and q is necessary for p [Scruton]
     Full Idea: If p entails q, then p is sufficient for q, and q is necessary for p.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 15.7)
2. Reason / E. Argument / 4. Open Question
We may define 'good' correctly, but then ask whether the application of the definition is good [Scruton]
     Full Idea: The 'open question' argument is clearly invalid. A question remains open just so long as our ignorance permits. …It may be an open question whether promoting happiness is good, even though this is what 'good' means.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 20.1)
     A reaction: A nice objection. Like small children, we can keep asking questions forever. Whether there is a question to be asked about a thing is not a property of that thing, but of us who ask it.
3. Truth / A. Truth Problems / 1. Truth
A true proposition is consistent with every other true proposition [Scruton]
     Full Idea: A true proposition is consistent with every other true proposition: no truth is contradicted by another.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 9.1)
     A reaction: Interesting. It resembles the rule that if you always tell the truth you don't need to remember what you said. Close to the heart of the concept of truth. Coherence and correspondence.
3. Truth / E. Pragmatic Truth / 1. Pragmatic Truth
The pragmatist does not really have a theory of truth [Scruton]
     Full Idea: The pragmatist does not really have a theory of truth.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 9.4)
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / a. Symbols of PL
The symbol 'ι' forms definite descriptions; (ιx)F(x) says 'the x which is such that F(x)' [Forbes,G]
     Full Idea: We use the symbol 'ι' (Greek 'iota') to form definite descriptions, reading (ιx)F(x) as 'the x which is such that F(x)', or simply as 'the F'.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.1)
     A reaction: Compare the lambda operator in modal logic, which picks out predicates from similar formulae.
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner]
     Full Idea: There are many coherent stopping points in the hierarchy of increasingly strong mathematical systems, starting with strict finitism, and moving up through predicativism to the higher reaches of set theory.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], Intro)
'Reflection principles' say the whole truth about sets can't be captured [Koellner]
     Full Idea: Roughly speaking, 'reflection principles' assert that anything true in V [the set hierarchy] falls short of characterising V in that it is true within some earlier level.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 2.1)
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / d. and
Is the meaning of 'and' given by its truth table, or by its introduction and elimination rules? [Forbes,G]
     Full Idea: The typical semantic account of validity for propositional connectives like 'and' presupposes that meaning is given by truth-tables. On the natural deduction view, the meaning of 'and' is given by its introduction and elimination rules.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.4)
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
We have no argument to show a statement is absolutely undecidable [Koellner]
     Full Idea: There is at present no solid argument to the effect that a given statement is absolutely undecidable.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 5.3)
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / c. Counting procedure
Could you be intellectually acquainted with numbers, but unable to count objects? [Scruton]
     Full Idea: Could someone have a perfect intellectual acquaintance with numbers, but be incapable of counting a flock of sheep?
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 26.6)
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
There are at least eleven types of large cardinal, of increasing logical strength [Koellner]
     Full Idea: Some of the standard large cardinals (in order of increasing (logical) strength) are: inaccessible, Mahlo, weakly compact, indescribable, Erdös, measurable, strong, Wodin, supercompact, huge etc. (...and ineffable).
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4)
     A reaction: [I don't understand how cardinals can have 'logical strength', but I pass it on anyway]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
PA is consistent as far as we can accept, and we expand axioms to overcome limitations [Koellner]
     Full Idea: To the extent that we are justified in accepting Peano Arithmetic we are justified in accepting its consistency, and so we know how to expand the axiom system so as to overcome the limitation [of Gödel's Second Theorem].
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.1)
     A reaction: Each expansion brings a limitation, but then you can expand again.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Arithmetical undecidability is always settled at the next stage up [Koellner]
     Full Idea: The arithmetical instances of undecidability that arise at one stage of the hierarchy are settled at the next.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4)
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / b. Intuitionism
If maths contains unprovable truths, then maths cannot be reduced to a set of proofs [Scruton]
     Full Idea: If there can be unprovable truths of mathematics, then mathematics cannot be reduced to the proofs whereby we construct it.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 26.7)
7. Existence / D. Theories of Reality / 10. Vagueness / d. Vagueness as linguistic
Vagueness problems arise from applying sharp semantics to vague languages [Forbes,G]
     Full Idea: It is very plausible that the sorites paradoxes arose from the application of a semantic apparatus appropriate only for sharp predicates to languages containing vague predicates (rather than from deficiency of meaning, or from incoherence).
     From: Graeme Forbes (The Metaphysics of Modality [1985], 7.3)
     A reaction: Sounds wrong. Of course, logic has been designed for sharp predicates, and natural languages are awash with vagueness. But the problems of vagueness bothered lawyers long before logicians like Russell began to worry about it.
8. Modes of Existence / B. Properties / 12. Denial of Properties
If possible worlds are needed to define properties, maybe we should abandon properties [Scruton]
     Full Idea: If the only way of defining properties involves quantifying over possible worlds, this could be taken as another reason for abandoning properties altogether.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 26.4)
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
In all instances of identity, there must be some facts to ensure the identity [Forbes,G]
     Full Idea: For each instance of identity or failure of identity, there must be facts in virtue of which that instance obtains. ..Enough has been said to lend this doctrine some plausibility.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.5)
     A reaction: Penelope Mackie picks this out from Forbes as a key principle. It sounds to be in danger of circularity, unless the 'facts' can be cited without referring to, or implicitly making use of, identities - which seems unlikely.
9. Objects / B. Unity of Objects / 3. Unity Problems / d. Coincident objects
If we combined two clocks, it seems that two clocks may have become one clock. [Forbes,G]
     Full Idea: If we imagine a possible world in which two clocks in a room make one clock from half the parts of each, the judgement 'these two actual clocks could have been a single clock' does not seem wholly false.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 7.4)
     A reaction: You would, of course, have sufficient parts left over to make a second clock, so they look like a destroyed clock, so I don't think I find Forbes's intuition on this one very persuasive.
9. Objects / D. Essence of Objects / 3. Individual Essences
Only individual essences will ground identities across worlds in other properties [Forbes,G, by Mackie,P]
     Full Idea: Forbes argues that, unless we posit individual essences, we cannot guarantee that identities across possible worlds will be appropriately grounded in other properties.
     From: report of Graeme Forbes (The Metaphysics of Modality [1985]) by Penelope Mackie - How Things Might Have Been 2.4
     A reaction: There is a confrontation between Wiggins, who says identity is primitive, and Forbes, who says identity must be grounded in other properties. I think I side with Forbes.
An individual essence is a set of essential properties which only that object can have [Forbes,G]
     Full Idea: An individual essence of an object x is a set of properties I which satisfies the following conditions: i. every property P in I is an essential property of x; ii. it is not possible that some object y distinct from x has every member of I.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: I am coming to the view that stable natural kinds (like electrons or gold) do not have individual essences, but complex kinds (like tigers or tables) do. The view is based on the idea that explanatory power is what individuates an essence.
Non-trivial individual essence is properties other than de dicto, or universal, or relational [Forbes,G]
     Full Idea: A non-trivial individual essence is properties other than a) those following from a de dicto truth, b) properties of existence and self-identity (or their cognates), c) properties derived from necessities in some other category.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: [I have compressed Forbes] Rather than adding all these qualificational clauses to our concept, we could just tighten up on the notion of a property, saying it is something which is causally efficacious, and hence explanatory.
9. Objects / D. Essence of Objects / 5. Essence as Kind
Essential properties depend on a category, and perhaps also on particular facts [Forbes,G]
     Full Idea: The essential properties of a thing will typically depend upon what category of thing it is, and perhaps also on some more particular facts about the thing itself.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: I see no way of dispensing with the second requirement, in the cases of complex entities like animals. If all samples are the same, then of course we can define a sample's essence through its kind, but not if samples differ in any way.
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
Essential properties are those without which an object could not exist [Forbes,G]
     Full Idea: An essential property of an object x is a property without possessing which x could not exist.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: This is certainly open to question. See Joan Kung's account of Aristotle on essence. I am necessarily more than eight years old (now), and couldn't exist without that property, but is the property part of my essence?
9. Objects / D. Essence of Objects / 11. Essence of Artefacts
Same parts does not ensure same artefact, if those parts could constitute a different artefact [Forbes,G]
     Full Idea: Sameness of parts is not sufficient for identity of artefacts at a world, since the very same parts may turn up at different times as the parts of artefacts with different designs and functions.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 7.2)
     A reaction: Thus the Ship of Theseus could be dismantled and turned into a barn (as happened with the 'Mayflower'). They could then be reconstituted as the ship, which would then have two beginnings (as Chris Hughes has pointed out).
Artefacts have fuzzy essences [Forbes,G]
     Full Idea: Artefacts can be ascribed fuzzy essences. ...We might say that it is essential to an artefact to have 'most' of its parts.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 7.6)
     A reaction: I think I prefer to accept the idea that essences are unstable things, in all cases. For all we know, electrons might subtly change their general character, or cease to be uniform, tomorrow. Essences explain, and what needs explaining changes.
9. Objects / E. Objects over Time / 12. Origin as Essential
An individual might change their sex in a world, but couldn't have differed in sex at origin [Forbes,G]
     Full Idea: In the time of a single world, the same individual can undergo a change of sex, but it is less clear that an individual of one sex could have been, from the outset, an individual of another.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 6.5)
     A reaction: I don't find this support for essentiality of origin very persuasive. I struggle with these ideas. Given my sex yesterday, then presumably I couldn't have had a different sex yesterday. Given that pigs can fly, pigs can fly. What am I missing?
9. Objects / F. Identity among Objects / 1. Concept of Identity
Identities must hold because of other facts, which must be instrinsic [Forbes,G, by Mackie,P]
     Full Idea: Forbes has two principles of identity, which we can call the No Bare Identities Principle (identities hold in virtue of other facts), and the No Extrinsic Determination Principle (that only intrinsic facts of a thing establish identity).
     From: report of Graeme Forbes (The Metaphysics of Modality [1985], 127-8) by Penelope Mackie - How Things Might Have Been 2.7
     A reaction: The job of the philosopher is to prise apart the real identities of things from the way in which we conceive of identities. I take these principles to apply to real identities, not conceptual identities.
10. Modality / A. Necessity / 4. De re / De dicto modality
De re modal formulae, unlike de dicto, are sensitive to transworld identities [Forbes,G]
     Full Idea: The difference between de re and de dicto formulae is a difference between formulae which are, and formulae which are not, sensitive to the identities of objects at various worlds.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 3.1)
10. Modality / A. Necessity / 11. Denial of Necessity
Hume assumes that necessity can only be de dicto, not de re [Scruton]
     Full Idea: It was one of the assumptions of Hume's empiricism that all necessities are de dicto: i.e. they are artefacts of language.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 13.5)
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
De re necessity is a form of conceptual necessity, just as de dicto necessity is [Forbes,G]
     Full Idea: De re necessity does not differ from de dicto necessity in respect of how it arises: it is still a form of conceptual necessity.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 9.4)
     A reaction: [Forbes proceeds to argue for this claim] Forbes defends a form of essentialism, but takes the necessity to arise from a posteriori truths because of the a priori involvement of other concepts (rather as Kripke argues).
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / c. Possible but inconceivable
The conceivable can't be a test of the possible, if there are things which are possible but inconceivable [Scruton]
     Full Idea: If there are things which are possible but inconceivable, we must abandon the view, which has had a considerable following since Descartes, that the conceivable is a test of the possible.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 25)
10. Modality / E. Possible worlds / 1. Possible Worlds / c. Possible worlds realism
Unlike places and times, we cannot separate possible worlds from what is true at them [Forbes,G]
     Full Idea: There is no means by which we might distinguish a possible world from what is true at it. ...Whereas our ability to separate a place, or a time, from its occupier is crucial to realism about places and times, as is a distance relation.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.2)
     A reaction: He is objecting to Lewis's modal realism. I'm not fully convinced. It depends whether we are discussing real ontology or conceptual space. In the latter I see no difference between times and possible worlds. In ontology, a 'time' is weird.
The problem with possible worlds realism is epistemological; we can't know properties of possible objects [Forbes,G]
     Full Idea: The main objection to realism about worlds is from epistemology. Knowledge of properties of objects requires experience of these objects, which must be within the range of our sensory faculties, but only concrete actual objects achieve that.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.2)
     A reaction: This pinpoints my dislike of the whole possible worlds framework, ontologically speaking. I seem to be an actualist. I take possibilities to be inferences to the best explanation from the powers we know of in the actual world. We experience potentiality.
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
Possible worlds are points of logical space, rather like other times than our own [Forbes,G]
     Full Idea: Someone impressed by the parallel between tense and modal operators ...might suggest that just as we can speak of places and times forming their own manifolds or spaces, so we can say that worlds are the points of logical space.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 4.2)
     A reaction: I particularly like the notion of worlds being "points of logical space", and am inclined to remove it from this context and embrace it as the correct way to understand possible worlds. We must understand logical or conceptual space.
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
Transworld identity concerns the limits of possibility for ordinary things [Forbes,G]
     Full Idea: An elucidation of transworld identity can be regarded as an elucidation of the boundaries of possibility for ordinary things.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: I presume that if we don't search for some such criterion, we just have to face the possibility that Aristotle could have been a poached egg in some possible world. To know the bounds of possibility, study the powers of actual objects.
The problem of transworld identity can be solved by individual essences [Forbes,G]
     Full Idea: The motivation for investigating individual essences should be obvious, since if every object has such an essence, the problem of elucidating transworld identity can be solved.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 5.1)
     A reaction: It is important that, if necessary, the identities be 'individual', and not just generic, by sortal, or natural kind. We want to reason about (and explain) truths at the fine-grained level of the individual, not just at the broad level of generalisation.
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
Counterpart theory is not good at handling the logic of identity [Forbes,G]
     Full Idea: The outstanding technical objection to counterpart-theoretic semantics concerns its handling of the logic of identity. In quantified S5 (the orthodox semantics) a = b → □(a = b) is valid, but 'a' must not attach to two objects.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 3.5)
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
Haecceitism attributes to each individual a primitive identity or thisness [Forbes,G]
     Full Idea: Haecceitism attributes to each individual a primitive identity or thisness, as opposed to the sort of essentialism that gives non-trivial conditions sufficient for transworld identity.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 6.6)
     A reaction: 'Haecceitism' is the doctrine that things have primitive identity. A 'haecceity' is a postulated property which actually does the job. The key point of the view is that whatever it is is 'primitive', and not complex, or analysable. I don't believe it.
We believe in thisnesses, because we reject bizarre possibilities as not being about that individual [Forbes,G]
     Full Idea: The natural response to an unreasonable hypothesis of possibility for an object x, that in such a state of affairs it would not be x which satisfies the conditions, is evidence that we do possess concepts of thisness for individuals.
     From: Graeme Forbes (The Metaphysics of Modality [1985], 9.4)
     A reaction: We may have a 'concept' of thisness, but we needn't be committed to the 'existence' of a thisness. There is a fairly universal intuition that cessation of existence of an entity when it starts to change can be a very vague matter.
11. Knowledge Aims / A. Knowledge / 1. Knowledge
Epistemology is about the justification of belief, not the definition of knowledge [Scruton]
     Full Idea: In my view the concept of knowledge is of no very great interest in epistemology, which actually concerns the justification of belief.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 22)
     A reaction: I think this is an excellent thought. I see knowledge as slippery, and partially contextual, and I don't care whether someone precisely 'knows' something. I just want to know why they believe it.
11. Knowledge Aims / B. Certain Knowledge / 4. The Cogito
In the Cogito argument consciousness develops into self-consciousness [Scruton]
     Full Idea: In the course of the argument the first person has acquired a character; he is not merely conscious, but self-conscious.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 4)
12. Knowledge Sources / A. A Priori Knowledge / 5. A Priori Synthetic
Maybe our knowledge of truth and causation is synthetic a priori [Scruton]
     Full Idea: 'Every event has a cause' and 'truth is correspondence to facts' are candidates for being synthetic a priori knowledge.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 13.2)
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / c. Primary qualities
Touch only seems to reveal primary qualities [Scruton]
     Full Idea: Touch seems to deliver a purely primary-quality account of the world.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 24)
     A reaction: Interesting, though a little over-confident. It seems occasionally possible for touch to be an illusion.
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / e. Primary/secondary critique
We only conceive of primary qualities as attached to secondary qualities [Scruton]
     Full Idea: Bradley argued that we cannot conceive of primary qualities except as attached to secondary qualities.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 10.1)
If primary and secondary qualities are distinct, what has the secondary qualities? [Scruton]
     Full Idea: If primary and secondary qualities are distinct, what do secondary qualities inhere in?
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], Ch.10 n)
     A reaction: What is the problem? A pin causes me pain, but I know the pain isn't in the pin. It is the same with colour. It is a mental property, if you like, triggered by a wavelength of radiation.
12. Knowledge Sources / B. Perception / 3. Representation
The representational theory says perceptual states are intentional states [Scruton]
     Full Idea: The representational theory is the unsurprising view that perceptual states are intentional, like beliefs, emotions and desires.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 23.3)
13. Knowledge Criteria / C. External Justification / 2. Causal Justification
My belief that it will rain tomorrow can't be caused by its raining tomorrow [Scruton]
     Full Idea: It is impossible that my present belief that it will rain tomorrow is caused by its raining tomorrow.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 22.4)
     A reaction: This doesn't demolish a causal account of belief. It would be very surprising if I were to believe it was going to rain tomorrow for no cause whatsoever. That would be irrational.
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
Logical positivism avoids scepticism, by closing the gap between evidence and conclusion [Scruton]
     Full Idea: If the evidence for p is q, and that is the only evidence there is or can be, then 'p' means q. Hence there is no gap between evidence and conclusion, and the sceptical problem does not arise.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 3.2)
13. Knowledge Criteria / E. Relativism / 6. Relativism Critique
Why should you believe someone who says there are no truths? [Scruton]
     Full Idea: A writer who says that there are no truths, or that all truth is 'merely relative', is asking you not to believe him. So don't.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 1.1)
16. Persons / F. Free Will / 6. Determinism / a. Determinism
Every event having a cause, and every event being determined by its cause, are not the same [Scruton]
     Full Idea: To say that every event has a cause is one thing; to say that every event is determined by its cause is quite another thing.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 17.1)
17. Mind and Body / A. Mind-Body Dualism / 2. Interactionism
The very concept of a substance denies the possibility of mutual interaction and dependence [Scruton]
     Full Idea: It is often held to be a consequence of the rationalist conception of substance, that separate substances cannot interact (since causal interaction is a form of mutual dependence).
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], Ch.16 n)
     A reaction: Yes, substances seem incapable of interaction, just as Leibniz argues that perfections could never interact. They are too pure.
19. Language / F. Communication / 4. Private Language
Wittgenstein makes it impossible to build foundations from something that is totally private [Scruton]
     Full Idea: Wittgenstein's point is that if I search for foundations in what can only be known to me, then the belief that I have discovered those foundations will also fall victim to Descartes' demon.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 5.3)
     A reaction: Why should foundations based in wider society or a language community fare any better? Getting a lot of people to agree won't trouble the demon too much. Flat earthers.
23. Ethics / B. Contract Ethics / 5. Free Rider
Any social theory of morality has the problem of the 'free rider', who only pretends to join in [Scruton]
     Full Idea: Any attempt to provide a social justification of morality runs the risk of the 'free rider' - one who pretends to play the game in order to enjoy the fruits of it.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 20.6)
23. Ethics / D. Deontological Ethics / 2. Duty
Membership is the greatest source of obligation [Scruton]
     Full Idea: Membership is the greatest source of obligation.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 11.2)
     A reaction: An interesting and rather Aristotelian idea. The alternative is individual debt or obligation.
23. Ethics / D. Deontological Ethics / 4. Categorical Imperative
The categorical imperative is not just individual, but can be used for negotiations between strangers [Scruton]
     Full Idea: The categorical imperative is also an instrument of negotiation and compromise between strangers, through which they can rise out of enmity and confront each other as equals.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 20.6)
26. Natural Theory / C. Causation / 1. Causation
'Cause' used to just mean any valid explanation [Scruton]
     Full Idea: Traditionally (before Leibniz and Spinoza) the world 'cause' signified any valid explanation.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 14)
27. Natural Reality / C. Space / 4. Substantival Space
Measuring space requires no movement while I do it [Scruton]
     Full Idea: I can measure the length of something only if I know that it has not moved between the moment when I locate one end of it and the moment when I locate the other.
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 25.3)
     A reaction: A nice example of how even simple propositions have many presuppositions.
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
'Existence' is not a predicate of 'man', but of the concept of man, saying it has at least one instance [Scruton]
     Full Idea: When I say that a man exists, Frege argues, I do not predicate existence of a man, but rather of the concept man: I say the concept has at least one instance (and existence is a predicate of predicates).
     From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 26.2)