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All the ideas for 'works', 'Logic for Philosophy' and 'Liberalism: the basics'

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97 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.
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?
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / b. Terminology of PL
'Theorems' are formulas provable from no premises at all [Sider]
     Full Idea: Formulas provable from no premises at all are often called 'theorems'.
     From: Theodore Sider (Logic for Philosophy [2010], 2.6)
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
Truth tables assume truth functionality, and are just pictures of truth functions [Sider]
     Full Idea: The method of truth tables assumes truth functionality. Truth tables are just pictures of truth functions.
     From: Theodore Sider (Logic for Philosophy [2010], 6.3)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / c. System D
Intuitively, deontic accessibility seems not to be reflexive, but to be serial [Sider]
     Full Idea: Deontic accessibility seems not to be reflexive (that it ought to be true doesn't make it true). One could argue that it is serial (that there is always a world where something is acceptable).
     From: Theodore Sider (Logic for Philosophy [2010], 6.3.1)
In D we add that 'what is necessary is possible'; then tautologies are possible, and contradictions not necessary [Sider]
     Full Idea: In D we add to K a new axiom saying that 'what's necessary is possible' (□φ→◊φ), ..and it can then be proved that tautologies are possible and contradictions are not necessary.
     From: Theodore Sider (Logic for Philosophy [2010], 6.4.2)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / f. System B
System B introduces iterated modalities [Sider]
     Full Idea: With system B we begin to be able to say something about iterated modalities. ..S4 then takes a different stand on the iterated modalities, and neither is an extension of the other.
     From: Theodore Sider (Logic for Philosophy [2010], 6.4.4)
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
S5 is the strongest system, since it has the most valid formulas, because it is easy to be S5-valid [Sider]
     Full Idea: S5 is the strongest system, since it has the most valid formulas. That's because it has the fewest models; it's easy to be S5-valid since there are so few potentially falsifying models. K is the weakest system, for opposite reasons.
     From: Theodore Sider (Logic for Philosophy [2010], 6.3.2)
     A reaction: Interestingly, the orthodox view is that S5 is the correct logic for metaphysics, but it sounds a bit lax. Compare Idea 13707.
4. Formal Logic / D. Modal Logic ML / 5. Epistemic Logic
Epistemic accessibility is reflexive, and allows positive and negative introspection (KK and K¬K) [Sider]
     Full Idea: Epistemic accessibility should be required to be reflexive (allowing Kφ→φ). S4 allows the 'KK principle', or 'positive introspection' (Kφ→KKφ), and S5 allows 'negative introspection' (¬Kφ→K¬Kφ).
     From: Theodore Sider (Logic for Philosophy [2010], 7.2)
4. Formal Logic / D. Modal Logic ML / 6. Temporal Logic
We can treat modal worlds as different times [Sider]
     Full Idea: We can think of the worlds of modal logic as being times, rather than 'possible' worlds.
     From: Theodore Sider (Logic for Philosophy [2010], 7.3.3)
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
Converse Barcan Formula: □∀αφ→∀α□φ [Sider]
     Full Idea: The Converse Barcan Formula reads □∀αφ→∀α□φ (or an equivalent using ◊).
     From: Theodore Sider (Logic for Philosophy [2010], 9.5.2)
     A reaction: I would read that as 'if all the αs happen to be φ, then αs have to be φ'. Put like that, I would have thought that it was obviously false. Sider points out that some new object could turn up which isn't φ.
The Barcan Formula ∀x□Fx→□∀xFx may be a defect in modal logic [Sider]
     Full Idea: The Barcan Formula ∀x□Fx→□∀xFx is often regarded as a defect of Simple Quantified Modal Logic, though this most clearly seen in its equivalent form ◊∃xFx→∃x◊Fx.
     From: Theodore Sider (Logic for Philosophy [2010], 9.5.2)
     A reaction: [See Idea 13719 for an explanation why it might be a defect] I translate the first one as 'if xs must be F, then they are always F', and the second one as 'for x to be possibly F, there must exist an x which is possibly F'. Modality needs existence.
System B is needed to prove the Barcan Formula [Sider]
     Full Idea: The proof of the Barcan Formula require System B.
     From: Theodore Sider (Logic for Philosophy [2010], 9.7)
4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
You can employ intuitionist logic without intuitionism about mathematics [Sider]
     Full Idea: Not everyone who employs intuitionistic logic is an intuitionist about mathematics.
     From: Theodore Sider (Logic for Philosophy [2010], 7.4.1)
     A reaction: This seems worthy of note, since it may be tempting to reject the logic because of the implausibility of the philosophy of mathematics. I must take intuitionist logic more seriously.
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 / B. Logical Consequence / 1. Logical Consequence
The most popular account of logical consequence is the semantic or model-theoretic one [Sider]
     Full Idea: On the question of the nature of genuine logical consequence, ...the most popular answer is the semantic, or model-theoretic one.
     From: Theodore Sider (Logic for Philosophy [2010], 1.5)
     A reaction: Reading the literature, one might be tempted to think that this is the only account that anyone takes seriously. Substitutional semantics seems an interesting alternative.
Maybe logical consequence is impossibility of the premises being true and the consequent false [Sider]
     Full Idea: The 'modal' account of logical consequence is that it is not possible for the premises to be true and the consequent false (under some suitable notion of possibility).
     From: Theodore Sider (Logic for Philosophy [2010], 1.5)
     A reaction: Sider gives a nice summary of five views of logical consequence, to which Shapiro adds substitutional semantics.
Maybe logical consequence is a primitive notion [Sider]
     Full Idea: There is a 'primitivist' account, according to which logical consequence is a primitive notion.
     From: Theodore Sider (Logic for Philosophy [2010], 1.5)
     A reaction: While sympathetic to substitutional views (Idea 13674), the suggestion here pushes me towards thinking that truth must be at the root of it. The trouble, though, is that a falsehood can be a good logical consequence of other falsehoods.
Maybe logical consequence is more a matter of provability than of truth-preservation [Sider]
     Full Idea: Another answer to the question about the nature of logical consequence is a proof-theoretic one, according to which it is more a matter of provability than of truth-preservation.
     From: Theodore Sider (Logic for Philosophy [2010], 1.5)
     A reaction: I don't like this, and prefer the model-theoretic or substitutional accounts. Whether you can prove that something is a logical consequence seems to me entirely separate from whether you can see that it is so. Gödel seems to agree.
5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
A 'theorem' is an axiom, or the last line of a legitimate proof [Sider]
     Full Idea: A 'theorem' is defined as the last line of a proof in which each line is either an axiom or follows from earlier lines by a rule.
     From: Theodore Sider (Logic for Philosophy [2010], 9.7)
     A reaction: In other words, theorems are the axioms and their implications.
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 / E. Structures of Logic / 4. Variables in Logic
When a variable is 'free' of the quantifier, the result seems incapable of truth or falsity [Sider]
     Full Idea: When a variable is not combined with a quantifier (and so is 'free'), the result is, intuitively, semantically incomplete, and incapable of truth or falsity.
     From: Theodore Sider (Logic for Philosophy [2010], 4.2)
5. Theory of Logic / E. Structures of Logic / 5. Functions in Logic
A 'total' function must always produce an output for a given domain [Sider]
     Full Idea: Calling a function a 'total' function 'over D' means that the function must have a well-defined output (which is a member of D) whenever it is given as inputs any n members of D.
     From: Theodore Sider (Logic for Philosophy [2010], 5.2)
5. Theory of Logic / F. Referring in Logic / 3. Property (λ-) Abstraction
λ can treat 'is cold and hungry' as a single predicate [Sider]
     Full Idea: We might prefer λx(Fx∧Gx)(a) as the symbolization of 'John is cold and hungry', since it treats 'is cold and hungry' as a single predicate.
     From: Theodore Sider (Logic for Philosophy [2010], 5.5)
5. Theory of Logic / H. Proof Systems / 2. Axiomatic Proof
Good axioms should be indisputable logical truths [Sider]
     Full Idea: Since they are the foundations on which a proof rests, the axioms in a good axiomatic system ought to represent indisputable logical truths.
     From: Theodore Sider (Logic for Philosophy [2010], 2.6)
No assumptions in axiomatic proofs, so no conditional proof or reductio [Sider]
     Full Idea: Axiomatic systems do not allow reasoning with assumptions, and therefore do not allow conditional proof or reductio ad absurdum.
     From: Theodore Sider (Logic for Philosophy [2010], 2.6)
     A reaction: Since these are two of the most basic techniques of proof which I have learned (in Lemmon), I shall avoid axiomatic proof systems at all costs, despites their foundational and Ockhamist appeal.
5. Theory of Logic / H. Proof Systems / 3. Proof from Assumptions
Induction has a 'base case', then an 'inductive hypothesis', and then the 'inductive step' [Sider]
     Full Idea: A proof by induction starts with a 'base case', usually that an atomic formula has some property. It then assumes an 'inductive hypothesis', that the property is true up to a certain case. The 'inductive step' then says it will be true for the next case.
     From: Theodore Sider (Logic for Philosophy [2010], 2.7)
     A reaction: [compressed]
Proof by induction 'on the length of the formula' deconstructs a formula into its accepted atoms [Sider]
     Full Idea: The style of proof called 'induction on formula construction' (or 'on the number of connectives', or 'on the length of the formula') rest on the fact that all formulas are built up from atomic formulas according to strict rules.
     From: Theodore Sider (Logic for Philosophy [2010], 2.7)
     A reaction: Hence the proof deconstructs the formula, and takes it back to a set of atomic formulas have already been established.
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
Natural deduction helpfully allows reasoning with assumptions [Sider]
     Full Idea: The method of natural deduction is popular in introductory textbooks since it allows reasoning with assumptions.
     From: Theodore Sider (Logic for Philosophy [2010], 2.5)
     A reaction: Reasoning with assumptions is generally easier, rather than being narrowly confined to a few tricky axioms, You gradually show that an inference holds whatever the assumption was, and so end up with the same result.
5. Theory of Logic / H. Proof Systems / 6. Sequent Calculi
We can build proofs just from conclusions, rather than from plain formulae [Sider]
     Full Idea: We can construct proofs not out of well-formed formulae ('wffs'), but out of sequents, which are some premises followed by their logical consequence. We explicitly keep track of the assumptions upon which the conclusion depends.
     From: Theodore Sider (Logic for Philosophy [2010], 2.5.1)
     A reaction: He says the method of sequents was invented by Gerhard Gentzen (the great nazi logician) in 1935. The typical starting sequents are the introduction and elimination rules. E.J. Lemmon's book, used in this database, is an example.
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
Valuations in PC assign truth values to formulas relative to variable assignments [Sider]
     Full Idea: A valuation function in predicate logic will assign truth values to formulas relative to variable assignments.
     From: Theodore Sider (Logic for Philosophy [2010], 4.2)
     A reaction: Sider observes that this is a 'double' relativisation (due to Tarski), since propositional logic truth was already relative to an interpretation. Now we are relative to variable assignments as well.
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
The semantical notion of a logical truth is validity, being true in all interpretations [Sider]
     Full Idea: The semantical notion of a logical truth is that of a valid formula, which is true in all interpretations. In propositional logic they are 'tautologies'.
     From: Theodore Sider (Logic for Philosophy [2010], 2.3)
     A reaction: This implies that there is a proof-theoretic account of logical truth as well. Intuitively a logical truth is a sequent which holds no matter which subject matter it refers to, so the semantic view sounds OK.
It is hard to say which are the logical truths in modal logic, especially for iterated modal operators [Sider]
     Full Idea: It isn't clear which formulas of modal propositional logic are logical truths, ...especially for sentences that contain iterations of modal operators. Is □P→□□P a logical truth? It's hard to say.
     From: Theodore Sider (Logic for Philosophy [2010], 6.3)
     A reaction: The result, of course, is that there are numerous 'systems' for modal logic, so that you can choose the one that gives you the logical truths you want. His example is valid in S4 and S5, but not in the others.
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
In model theory, first define truth, then validity as truth in all models, and consequence as truth-preservation [Sider]
     Full Idea: In model theory one normally defines some notion of truth in a model, and then uses it to define validity as truth in all models, and semantic consequence as the preservation of truth in models.
     From: Theodore Sider (Logic for Philosophy [2010], 10.1)
5. Theory of Logic / K. Features of Logics / 4. Completeness
In a complete logic you can avoid axiomatic proofs, by using models to show consequences [Sider]
     Full Idea: You can establish facts of the form Γ|-φ while avoiding the agonies of axiomatic proofs by reasoning directly about models to conclusions about semantic consequence, and then citing completeness.
     From: Theodore Sider (Logic for Philosophy [2010], 4.5)
     A reaction: You cite completeness by saying that anything which you have shown to be a semantic consequence must therefore be provable (in some way).
5. Theory of Logic / K. Features of Logics / 6. Compactness
Compactness surprisingly says that no contradictions can emerge when the set goes infinite [Sider]
     Full Idea: Compactness is intuitively surprising, ..because one might have thought there could be some contradiction latent within some infinite set, preventing it from being satisfiable, only discovered when you consider the whole set. But this can't happen.
     From: Theodore Sider (Logic for Philosophy [2010], 4.5)
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
A single second-order sentence validates all of arithmetic - but this can't be proved axiomatically [Sider]
     Full Idea: A single second-order sentence has second-order semantic consequences which are all and only the truths of arithmetic, but this is cold comfort because of incompleteness; no axiomatic system draws out the consequences of this axiom.
     From: Theodore Sider (Logic for Philosophy [2010], 5.4.3)
7. Existence / D. Theories of Reality / 10. Vagueness / f. Supervaluation for vagueness
A 'precisification' of a trivalent interpretation reduces it to a bivalent interpretation [Sider]
     Full Idea: For a 'precisification' we take a trivalent interpretation and preserve the T and F values, and then assign all the third values in some way to either T or F.
     From: Theodore Sider (Logic for Philosophy [2010], 3.4.5)
     A reaction: [my informal summary of Sider's formal definition]
A 'supervaluation' assigns further Ts and Fs, if they have been assigned in every precisification [Sider]
     Full Idea: In a 'supervaluation' we take a trivalent interpretation, and assign to each wff T (or F) if it is T (or F) in every precisification, leaving the third truth-value in any other cases. The wffs are then 'supertrue' or 'superfalse' in the interpretation.
     From: Theodore Sider (Logic for Philosophy [2010], 3.4.5)
     A reaction: [my non-symbolic summary] Sider says the Ts and Fs in the precisifications are assigned 'in any way you like', so supervaluation is a purely formal idea, not a technique for eliminating vagueness.
Supervaluational logic is classical, except when it adds the 'Definitely' operator [Sider]
     Full Idea: Supervaluation preserves classical logic (even though supervaluations are three-valued), except when we add the Δ operator (meaning 'definitely' or 'determinately').
     From: Theodore Sider (Logic for Philosophy [2010], 3.4.5)
We can 'sharpen' vague terms, and then define truth as true-on-all-sharpenings [Sider]
     Full Idea: We can introduce 'sharpenings', to make vague terms precise without disturbing their semantics. Then truth (or falsity) becomes true(false)-in-all-sharpenings. You are only 'rich' if you are rich-on-all-sharpenings of the word.
     From: Theodore Sider (Logic for Philosophy [2010], 3.4.5)
     A reaction: Not very helpful. Lots of people might be considered rich in many contexts, but very few people would be considered rich in all contexts. You are still left with some vague middle ground.
8. Modes of Existence / A. Relations / 1. Nature of Relations
A relation is a feature of multiple objects taken together [Sider]
     Full Idea: A relation is just a feature of multiple objects taken together.
     From: Theodore Sider (Logic for Philosophy [2010], 1.8)
     A reaction: Appealingly simple, especially for a logician, who can then just list the relevant objects as members of a set, and the job is done. But if everyone to the left of me is also taller than me, this won't quite do.
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 / F. Identity among Objects / 7. Indiscernible Objects
The identity of indiscernibles is necessarily true, if being a member of some set counts as a property [Sider]
     Full Idea: The identity of indiscernibles (∀x∀y(∀X(Xx↔Xy)→x=y) is necessarily true, provided that we construe 'property' very broadly, so that 'being a member of such-and-such set' counts as a property.
     From: Theodore Sider (Logic for Philosophy [2010], 5.4.3)
     A reaction: Sider's example is that if the two objects are the same they must both have the property of being a member of the same singleton set, which they couldn't have if they were different.
10. Modality / A. Necessity / 3. Types of Necessity
'Strong' necessity in all possible worlds; 'weak' necessity in the worlds where the relevant objects exist [Sider]
     Full Idea: 'Strong necessity' requires the truth of 'necessarily φ' is all possible worlds. 'Weak necessity' merely requires that 'necessarily φ' be true in all worlds in which objects referred to within φ exist.
     From: Theodore Sider (Logic for Philosophy [2010], 9.6.3)
     A reaction: This seems to be a highly desirably distinction, given the problem of Idea 13719. It is weakly necessary that humans can't fly unaided, assuming we are referring the current feeble wingless species. That hardly seems to be strongly necessary.
10. Modality / A. Necessity / 5. Metaphysical Necessity
Maybe metaphysical accessibility is intransitive, if a world in which I am a frog is impossible [Sider]
     Full Idea: Some argue that metaphysical accessibility is intransitive. The individuals involved mustn't be too different from the actual world. A world in which I am a frog isn't metaphysically possible. Perhaps the logic is modal system B or T.
     From: Theodore Sider (Logic for Philosophy [2010], 6.3.1)
     A reaction: This sounds rather plausible and attractive to me. We don't want to say that I am necessarily the way I actually am, though, so we need criteria. Essence!
10. Modality / A. Necessity / 6. Logical Necessity
Logical truths must be necessary if anything is [Sider]
     Full Idea: On any sense of necessity, surely logical truths must be necessary.
     From: Theodore Sider (Logic for Philosophy [2010], 6.4)
10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional
'If B hadn't shot L someone else would have' if false; 'If B didn't shoot L, someone else did' is true [Sider]
     Full Idea: To show the semantic difference between counterfactuals and indicative conditionals, 'If Booth hadn't shot Lincoln someone else would have' is false, but 'If Booth didn't shoot Lincoln then someone else did' is true.
     From: Theodore Sider (Logic for Philosophy [2010], 8)
     A reaction: He notes that indicative conditionals also differ in semantics from material and strict conditionals. The first example allows a world where Lincoln was not shot, but the second assumes our own world, where he was. Contextual domains?
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
Transworld identity is not a problem in de dicto sentences, which needn't identify an individual [Sider]
     Full Idea: There is no problem of transworld identification with de dicto modal sentence, for their evaluation does not require taking an individual from one possible world and reidentifying it in another.
     From: Theodore Sider (Logic for Philosophy [2010], 9.2)
     A reaction: If 'de dicto' is about the sentence and 'de re' is about the object (Idea 5732), how do you evaluate the sentence without at least some notion of the object to which it refers. Nec the Prime Minister chairs the cabinet. Could a poached egg do the job?
10. Modality / E. Possible worlds / 3. Transworld Objects / e. Possible Objects
Barcan Formula problem: there might have been a ghost, despite nothing existing which could be a ghost [Sider]
     Full Idea: A problem with the Barcan Formula is it might be possible for there to exist a ghost, even though there in fact exists nothing that could be a ghost. There could have existed some 'extra' thing which could be a ghost.
     From: Theodore Sider (Logic for Philosophy [2010], 9.5.2)
     A reaction: Thus when we make modal claims, do they only refer to what actually exists, or is specified in our initial domain? Can a claim enlarge the domain? Are domains 'variable'? Simple claims about what might have existed seem to be a problem.
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 / 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 / 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 / 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.
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.
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!
24. Political Theory / A. Basis of a State / 4. Original Position / a. Original position
Rawls's theory cannot justify liberalism, since it presupposes free and equal participants [Charvet]
     Full Idea: Rawls's theory presupposes that the contractors are conceived, and conceive themselves, to be free and equal persons. Consequently, the theory cannot be presented as a justificatory theory of liberalism.
     From: John Charvet (Liberalism: the basics [2019], 14)
     A reaction: Nice. If you imagine diverse groups with many strong beliefs coming together to form a society, Rawls is asking them all to become liberals before they all decide how to live together.
24. Political Theory / A. Basis of a State / 4. Original Position / b. Veil of ignorance
People with strong prior beliefs would have nothing to do with a veil of ignorance [Charvet]
     Full Idea: Why would a group of people with strong beliefs (e.g. religious beliefs) agree to debate the problem of what norms should govern their association from behind a veil of ignorance? …They would not accept the veil of ignorance as fair.
     From: John Charvet (Liberalism: the basics [2019], 14)
     A reaction: Nice. Rawls's experiment assumes liberal people with very few beliefs. No racial supremacist is going to enter a society in which they may be of a different race. Charvet says the entrants would all need to be pluralists about the good.
24. Political Theory / D. Ideologies / 3. Conservatism
Societies need shared values, so conservatism is right if rational discussion of values is impossible [Charvet]
     Full Idea: Were it true that rational discussion of values is impossible, then a conservative attitude would seem to be the only viable position. Some set of common values is necessary to maintain the unity of a political society.
     From: John Charvet (Liberalism: the basics [2019], 07)
     A reaction: Better to say that the less values can be both discussed and changed the stronger is the case for a degree of conservatism. Conservatives tend to favour values asserted by authority, rather than by popular (undiscussed) consensus.
24. Political Theory / D. Ideologies / 4. Social Utilitarianism
The universalism of utilitarianism implies a world state [Charvet]
     Full Idea: Utilitarianism is a universalist ethic, so the political realisation of this ethic would seem to be a world state seeking to maximise happiness for the world's population.
     From: John Charvet (Liberalism: the basics [2019], 12)
     A reaction: It certainly doesn't seem to favour the citizens of the state where it is implemented, since miserable people just across the border would have priority, and all miserable migrants must be welcomed. There is no loyalty to citizens.
24. Political Theory / D. Ideologies / 6. Liberalism / a. Liberalism basics
Liberals value freedom and equality, but the society itself must decide on its values [Charvet]
     Full Idea: While freedom and equality are liberal values …they are fundamental regulative ideas of an independent society that is self-regulating …and decides what its own social and political arrangements should be.
     From: John Charvet (Liberalism: the basics [2019], 06)
     A reaction: So the central political activity is persuasion, not enforcement. Illiberal societies all contain liberal individuals.
24. Political Theory / D. Ideologies / 6. Liberalism / b. Liberal individualism
Modern libertarian societies still provide education and some housing [Charvet]
     Full Idea: No society today is libertarian in the extreme sense. Even the freest economically, such as Singapore have their governments provide education services and public housing.
     From: John Charvet (Liberalism: the basics [2019], 05)
     A reaction: There is a good argument that many other services should be provided by a libertarian state, on the grounds that it is more efficient, and the services must otherwise paid for by much higher salaries.
Liberalism needs people to either have equal autonomy, or everyone to have enough autonomy [Charvet]
     Full Idea: To get a liberal society one would have to claim that either everyone possesses autonomy to an equal degree or that everyone possesses a threshold level of the capacity that entitles them to enjoy the full liberal rights.
     From: John Charvet (Liberalism: the basics [2019], 07)
     A reaction: This leaves out the more right-wing attitude that people can increase their capacity for autonomy if they are forced to stand on their own feet. A liberal society must decide how to treat persons incapable of proper autonomy.
Kant places a higher value on the universal rational will than on the people asserting it [Charvet]
     Full Idea: For Kant what is of absolute worth is the universal rational will which become an individual's actual will. Insofar as the individual fails to will the universal, they have no absolute worth, so whether or not they exist is unimportant.
     From: John Charvet (Liberalism: the basics [2019], 14)
     A reaction: A lovely demolition of the claims of Kant to be the patriarch of liberalism! Liberalism must place supreme value on each individual, not on some abstracted realm of pure reason and moral good. Liberals are motivated by love, not reason.
24. Political Theory / D. Ideologies / 6. Liberalism / c. Liberal equality
Liberalism asserts maximum freedom, but that must be equal for all participants [Charvet]
     Full Idea: Liberalism attaches fundamental value to leaving individuals as free as possible … - but there is another fundamental value implicit in this idea - the equal status of the participants in the practice. By this I mean that they all have the same rights.
     From: John Charvet (Liberalism: the basics [2019], Intro)
     A reaction: Libertarian liberalism (e.g. Nozick) only asserts the fundament principle of freedom, but such a society swiftly deprives most of its members of those very freedoms. Egalitarian Liberalism should be our default political ideology.
Egalitarian liberals prefer equality (either of input or outcome) to liberty [Charvet]
     Full Idea: Rather than libertarianism, egalitarian liberals promote equality, either of outcomes (of happiness or of well-being), or of inputs (such as opportunities, capacities or resources), which they favour ahead of freedom.
     From: John Charvet (Liberalism: the basics [2019], 06)
     A reaction: This is my team, I think. I think I'm a liberal who thinks liberty is a bit overrated. Equal outcome according to capacity (promoted by Nussbaum) seems attractive.
24. Political Theory / D. Ideologies / 6. Liberalism / e. Liberal community
Liberals promote community and well-being - because all good societies need them [Charvet]
     Full Idea: Community and well-being are not specifically liberal values. They are values any independent political society must pursue whether it is a liberal society or not.
     From: John Charvet (Liberalism: the basics [2019], Intro)
     A reaction: This seems, at a stroke, to undermine the familiar debate between liberals and communitarians. I've switched to the former from the latter, because communitarians is potentially too paternalistic and conservative. Persuade individuals to be communal!
24. Political Theory / D. Ideologies / 6. Liberalism / f. Multiculturalism
Identity multiculturalism emerges from communitarianism, preferring community to humanity [Charvet]
     Full Idea: Identity-based multiculturalism developed from communitarianism. …People come to consciousness of themselves as members of some community before they identify themselves as members of the human race.
     From: John Charvet (Liberalism: the basics [2019], 08)
     A reaction: This is 'identity politics', which Carvet sees as a problem from liberalism. Is it more important to be a woman or a Muslim or a Scot than to be a human being? It seems to create institutional antagonisms.
24. Political Theory / D. Ideologies / 7. Communitarianism / b. Against communitarianism
For communitarians it seems that you must accept the culture you are born into [Charvet]
     Full Idea: Communitarians have difficulty avoiding the relativist trap. It seems they must claim that if one is born into a liberal society one cannot but be a liberal, and if one is born into a communist society one cannot but be a communist.
     From: John Charvet (Liberalism: the basics [2019], 08)
     A reaction: Anyone who accepts the Hegelian view of history and culture seems doomed to such relativism, and Hegel is a communitarian precursor. This is a good reason for me to reject communitarianism, after a long flirtation. We can criticise our own culture.
24. Political Theory / D. Ideologies / 9. Communism
Give by ability and receive by need, rather than a free labour market [Charvet]
     Full Idea: Only the most extreme collective socialism denies the freedom to sell one's labour power and buy that of others, under the communist slogan 'from each according to his ability, and to each according to his needs'.
     From: John Charvet (Liberalism: the basics [2019], 05)
     A reaction: [He cites Marx 'Critique of the Gotha Programme'] I would guess that this practice is not abnormal in old traditional villages, though a community would be tempted to reward highly a very successful member.
25. Social Practice / A. Freedoms / 3. Free speech
Allowing defamatory speech is against society's interests, by blurring which people are trustworthy [Charvet]
     Full Idea: The argument for restricting defamatory speech is that unrestricted speech makes it impossible, or too difficult, to distinguish between those who deserve a trustworthy reputation and those who don't - a distinction in society's best interests.
     From: John Charvet (Liberalism: the basics [2019], 03)
     A reaction: A nice example of appeal to the common good, in opposition to the normal freedoms of liberalism. An example of the Prisoner's Dilemma. Should assertion of the common good of a group be a prime value of liberalism?
25. Social Practice / A. Freedoms / 5. Freedom of lifestyle
'Freedom from' is an empty idea, if the freedom is not from impediments to my desires [Charvet]
     Full Idea: Berlin's distinction of 'freedom from' and 'freedom to' is worthless …because to say that I want to be free from something for absolutely no reason makes no sense. Unfreedom is being blocked from what I want to do, which ceases if I no longer want it.
     From: John Charvet (Liberalism: the basics [2019], 07)
     A reaction: [compressed] The government could guarantee us against attacks by albatrosses, but we would hardly have a national holiday to celebrate the freedom. Still, there is freedom from incoming troubles, and freedom to output things.
Positive freedom can lead to coercion, if you are forced to do what you chose to do [Charvet]
     Full Idea: Berlin saw positive freedom as a justification for illiberal coercion. If I am positively free only in doing X, then if I am forced to do X, I will still be free.
     From: John Charvet (Liberalism: the basics [2019], 07)
     A reaction: I suppose Berlin is thinking of Russian farmers, who wanted to farm, but then found they were forced to do what they were going to do anyway. It's better than being forced to do what you didn't want to do. Forcing clearly isn't freedom.
First level autonomy is application of personal values; second level is criticising them [Charvet]
     Full Idea: First level autonomy is being able to apply one's scheme of values to one's actions and life; second level autonomy is being able to subject those values to critical evaluation.
     From: John Charvet (Liberalism: the basics [2019], 10)
     A reaction: Charvet sees this as a key issue for liberalism. How do you treat citizens who cannot advance beyond the first level? He mentions the elitism of Plato's Republic that results.
25. Social Practice / B. Equalities / 1. Grounds of equality
Mere equality, as in two trees being the same height, has no value at all [Charvet]
     Full Idea: That the relation of equality might be considered a value in itself is an absurdity. Would the equality of blinding the only sighted person in a blind society be good? Is it inherently good that two trees are the same height? This is nonsense.
     From: John Charvet (Liberalism: the basics [2019], 08)
     A reaction: He cites Temkin 1993 as defending the blinding example! Obviously equality is only possible in certain respects (though electrons might be equal in all respects). So the point is to identify the important respects. The rest is rhetoric.
25. Social Practice / B. Equalities / 4. Economic equality
Inequalities are worse if they seem to be your fault, rather than social facts [Charvet]
     Full Idea: Inequality is worse in a meritocracy than in a stratified society, because everyone enjoys a formal equality of status and your position in the social order is due to your merit or lack of merit, so you have only yourself to blame for being at the bottom.
     From: John Charvet (Liberalism: the basics [2019], 10)
     A reaction: This is the simple point that it is worse to lack some good if you might have possessed it, rather than it being entirely out of reach. It also makes the false assumption that people are largely responsible for their merit or lack of it (ignoring luck).
Money allows unlimited inequalities, and we obviously all agree to money [Charvet]
     Full Idea: The introduction of money allows people to accumulate wealth without limit. Since money only works through everyone's agreement …everyone can be taken to have agreed to the consequences of money in the unequal distribution of wealth.
     From: John Charvet (Liberalism: the basics [2019], 11)
     A reaction: [Locke] Presumably large inequalities of possessions and territory were possible before money, but there was at least an upper limit. The current owner of Amazon may end up with more wealth than the whole of the rest of humanity combined.
25. Social Practice / D. Justice / 2. The Law / b. Rule of law
The rule of law mainly benefits those with property and liberties [Charvet]
     Full Idea: A rule of law regime will primarily benefit those possessing property and liberty rights.
     From: John Charvet (Liberalism: the basics [2019], 02)
     A reaction: Important. It's no good fighting for the law if the law doesn't protect what you have got, or if you have got nothing to protect. Important steps must precede assertion of the rule of law.
From 1701 only parliament could remove judges, whose decisions could not be discussed [Charvet]
     Full Idea: In 1701 UK judges were given secure tenure, being removable only by parliament which at the same time undertook to follow a convention not to discuss particular judicial decisions.
     From: John Charvet (Liberalism: the basics [2019], 02)
     A reaction: In recent years the UK Daily Mail published the pictures of three judges, and labelled them 'traitors' because of their verdict about leaving the European Union.
The rule of law is mainly to restrict governments [Charvet]
     Full Idea: The rule of law is directed at the restriction of the power of governments as much, if not more, then the power of private individuals.
     From: John Charvet (Liberalism: the basics [2019], 02)
     A reaction: The more powerful you are the more restricting is the rule of law. Every government is tempted to change the law to expand its powers. The UK government has just legislated to restrict public demonstrations. Law is the people's weapon against autocrats.
Justice superior to the rule of law is claimed on behalf of the workers, or the will of the nation [Charvet]
     Full Idea: Communist leaders justify themselves as the embodiment of the people's will as workers, and fascist leaders as expressing the will of the nation. Both believe their policies contain a superior justice on this basis.
     From: John Charvet (Liberalism: the basics [2019], 02)
     A reaction: [compressed] A neat summary of why the rule of law might be rejected (other than by simple tyrrany justified only by force). In modern democracies recent right-wing governments have pushed back the law and attacked justice on this basis.
The 1689 Bill of Rights denied the monarch new courts, or the right to sit as judge [Charvet]
     Full Idea: The 1689 Bill of Rights said the monarch could not create new courts of law, or act as a judge at law.
     From: John Charvet (Liberalism: the basics [2019], 02)
     A reaction: The background was the abolition of the court of Star Chamber in 1641, which had been secret, severe, and controlled by the monarch. Is it possible to create a new type of court, or are we stuck with the current ones?
25. Social Practice / E. Policies / 3. Welfare provision
Welfare is needed if citizens are to accept the obligations of a liberal state [Charvet]
     Full Idea: The welfare state provides the background conditions under which it is reasonable to expect one's fellow citizens to commit to liberal principles of interaction, even if those conditions can only be achieved through a degree of compulsion.
     From: John Charvet (Liberalism: the basics [2019], 05)
     A reaction: You cannot expect people to accept the role of 'free' citizen if that is likely to result in swift misery. A liberal state will only command loyalty if it has a safety net. Fully committed liberalism implies modest socialism.
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 Michčle 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.
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).