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All the ideas for 'The Elm and the Expert', 'Paraconsistent Logic' and 'Intro to Gdel's Theorems'

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75 ideas

2. Reason / A. Nature of Reason / 8. Naturalising Reason
A standard naturalist view is realist, externalist, and computationalist, and believes in rationality [Fodor]
     Full Idea: There seems to be an emerging naturalist consensus that is Realist in ontology and epistemology, externalist in semantics, and computationalist in cognitive psychology, which nicely allows us to retain our understanding of ourselves as rational creatures.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
3. Truth / A. Truth Problems / 5. Truth Bearers
Psychology has to include the idea that mental processes are typically truth-preserving [Fodor]
     Full Idea: A psychology that can't make sense of such facts as that mental processes are typically truth-preserving is ipso facto dead in the water.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §1.3)
4. Formal Logic / E. Nonclassical Logics / 7. Paraconsistency
Paraconsistent reasoning can just mean responding sensibly to inconsistencies [Jago]
     Full Idea: A practical application of paraconsistent reasoning is in large databases. It does not mean that contradictions could be true, but only that we sometimes need to draw sensible conclusions from inconsistent data. 'Dialethists' believe some contradictions.
     From: Mark Jago (Paraconsistent Logic [2010])
     A reaction: Interesting as a more cautious and sensible attitude to the scandal of paraconsistency.
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
There cannot be a set theory which is complete [Smith,P]
     Full Idea: By Gödel's First Incompleteness Theorem, there cannot be a negation-complete set theory.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 01.3)
     A reaction: This means that we can never prove all the truths of a system of set theory.
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
Inferences are surely part of the causal structure of the world [Fodor]
     Full Idea: Inferences are surely part of the causal structure of the world.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §3)
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Second-order arithmetic can prove new sentences of first-order [Smith,P]
     Full Idea: Going second-order in arithmetic enables us to prove new first-order arithmetical sentences that we couldn't prove before.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 23.4)
     A reaction: The wages of Satan, perhaps. We can prove things about objects by proving things about their properties and sets and functions. Smith says this fact goes all the way up the hierarchy.
5. Theory of Logic / E. Structures of Logic / 5. Functions in Logic
A 'partial function' maps only some elements to another set [Smith,P]
     Full Idea: A 'partial function' is one which maps only some elements of a domain to elements in another set. For example, the reciprocal function 1/x is not defined for x=0.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.1 n1)
A 'total function' maps every element to one element in another set [Smith,P]
     Full Idea: A 'total function' is one which maps every element of a domain to exactly one corresponding value in another set.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.1)
An argument is a 'fixed point' for a function if it is mapped back to itself [Smith,P]
     Full Idea: If a function f maps the argument a back to a itself, so that f(a) = a, then a is said to be a 'fixed point' for f.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 20.5)
The 'range' of a function is the set of elements in the output set created by the function [Smith,P]
     Full Idea: The 'range' of a function is the set of elements in the output set that are values of the function for elements in the original set.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.1)
     A reaction: In other words, the range is the set of values that were created by the function.
Two functions are the same if they have the same extension [Smith,P]
     Full Idea: We count two functions as being the same if they have the same extension, i.e. if they pair up arguments with values in the same way.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 11.3)
     A reaction: So there's only one way to skin a cat in mathematical logic.
5. Theory of Logic / E. Structures of Logic / 7. Predicates in Logic
The Comprehension Schema says there is a property only had by things satisfying a condition [Smith,P]
     Full Idea: The so-called Comprehension Schema ∃X∀x(Xx ↔ φ(x)) says that there is a property which is had by just those things which satisfy the condition φ.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 22.3)
5. Theory of Logic / E. Structures of Logic / 8. Theories in Logic
A 'theorem' of a theory is a sentence derived from the axioms using the proof system [Smith,P]
     Full Idea: 'Theorem': given a derivation of the sentence φ from the axioms of the theory T using the background logical proof system, we will say that φ is a 'theorem' of the theory. Standard abbreviation is T |- φ.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 03.4)
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
A 'natural deduction system' has no axioms but many rules [Smith,P]
     Full Idea: A 'natural deduction system' will have no logical axioms but may rules of inference.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 09.1)
     A reaction: He contrasts this with 'Hilbert-style systems', which have many axioms but few rules. Natural deduction uses many assumptions which are then discharged, and so tree-systems are good for representing it.
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
No nice theory can define truth for its own language [Smith,P]
     Full Idea: No nice theory can define truth for its own language.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 21.5)
     A reaction: This leads on to Tarski's account of truth.
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
An 'injective' ('one-to-one') function creates a distinct output element from each original [Smith,P]
     Full Idea: An 'injective' function is 'one-to-one' - each element of the output set results from a different element of the original set.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.1)
     A reaction: That is, two different original elements cannot lead to the same output element.
A 'surjective' ('onto') function creates every element of the output set [Smith,P]
     Full Idea: A 'surjective' function is 'onto' - the whole of the output set results from the function being applied to elements of the original set.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.1)
A 'bijective' function has one-to-one correspondence in both directions [Smith,P]
     Full Idea: A 'bijective' function has 'one-to-one correspondence' - it is both surjective and injective, so that every element in each of the original and the output sets has a matching element in the other.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.1)
     A reaction: Note that 'injective' is also one-to-one, but only in the one direction.
5. Theory of Logic / K. Features of Logics / 3. Soundness
If everything that a theory proves is true, then it is 'sound' [Smith,P]
     Full Idea: If everything that a theory proves must be true, then it is a 'sound' theory.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 01.1)
Soundness is true axioms and a truth-preserving proof system [Smith,P]
     Full Idea: Soundness is normally a matter of having true axioms and a truth-preserving proof system.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 03.4)
     A reaction: The only exception I can think of is if a theory consisted of nothing but the axioms.
A theory is 'sound' iff every theorem is true (usually from true axioms and truth-preservation) [Smith,P]
     Full Idea: A theory is 'sound' iff every theorem of it is true (i.e. true on the interpretation built into its language). Soundness is normally a matter of having true axioms and a truth-preserving proof system.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 03.4)
5. Theory of Logic / K. Features of Logics / 4. Completeness
A theory is 'negation complete' if it proves all sentences or their negation [Smith,P]
     Full Idea: A theory is 'negation complete' if it decides every sentence of its language (either the sentence, or its negation).
     From: Peter Smith (Intro to Gödel's Theorems [2007], 03.4)
'Complete' applies both to whole logics, and to theories within them [Smith,P]
     Full Idea: There is an annoying double-use of 'complete': a logic may be semantically complete, but there may be an incomplete theory expressed in it.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 03.4)
A theory is 'negation complete' if one of its sentences or its negation can always be proved [Smith,P]
     Full Idea: Logicians say that a theory T is '(negation) complete' if, for every sentence φ in the language of the theory, either φ or ¬φ is deducible in T's proof system. If this were the case, then truth could be equated with provability.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 01.1)
     A reaction: The word 'negation' seems to be a recent addition to the concept. Presumable it might be the case that φ can always be proved, but not ¬φ.
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
Two routes to Incompleteness: semantics of sound/expressible, or syntax of consistency/proof [Smith,P]
     Full Idea: There are two routes to Incompleteness results. One goes via the semantic assumption that we are dealing with sound theories, using a result about what they can express. The other uses the syntactic notion of consistency, with stronger notions of proof.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 18.1)
5. Theory of Logic / K. Features of Logics / 7. Decidability
'Effective' means simple, unintuitive, independent, controlled, dumb, and terminating [Smith,P]
     Full Idea: An 'effectively decidable' (or 'computable') algorithm will be step-by-small-step, with no need for intuition, or for independent sources, with no random methods, possible for a dumb computer, and terminates in finite steps.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.2)
     A reaction: [a compressed paragraph]
A theory is 'decidable' if all of its sentences could be mechanically proved [Smith,P]
     Full Idea: A theory is 'decidable' iff there is a mechanical procedure for determining whether any sentence of its language can be proved.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 03.4)
     A reaction: Note that it doesn't actually have to be proved. The theorems of the theory are all effectively decidable.
Any consistent, axiomatized, negation-complete formal theory is decidable [Smith,P]
     Full Idea: Any consistent, axiomatized, negation-complete formal theory is decidable.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 03.6)
5. Theory of Logic / K. Features of Logics / 8. Enumerability
A set is 'enumerable' is all of its elements can result from a natural number function [Smith,P]
     Full Idea: A set is 'enumerable' iff either the set is empty, or there is a surjective function to the set from the set of natural numbers, so that the set is in the range of that function.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.3)
A set is 'effectively enumerable' if a computer could eventually list every member [Smith,P]
     Full Idea: A set is 'effectively enumerable' if an (idealised) computer could be programmed to generate a list of its members such that any member will eventually be mentioned (even if the list is empty, or without end, or contains repetitions).
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.4)
A finite set of finitely specifiable objects is always effectively enumerable (e.g. primes) [Smith,P]
     Full Idea: A finite set of finitely specifiable objects is always effectively enumerable (for example, the prime numbers).
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.4)
The set of ordered pairs of natural numbers <i,j> is effectively enumerable [Smith,P]
     Full Idea: The set of ordered pairs of natural numbers (i,j) is effectively enumerable, as proven by listing them in an array (across: <0,0>, <0,1>, <0,2> ..., and down: <0,0>, <1,0>, <2,0>...), and then zig-zagging.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 02.5)
The thorems of a nice arithmetic can be enumerated, but not the truths (so they're diffferent) [Smith,P]
     Full Idea: The theorems of any properly axiomatized theory can be effectively enumerated. However, the truths of any sufficiently expressive arithmetic can't be effectively enumerated. Hence the theorems and truths of arithmetic cannot be the same.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 05 Intro)
5. Theory of Logic / K. Features of Logics / 9. Expressibility
Being 'expressible' depends on language; being 'capture/represented' depends on axioms and proof system [Smith,P]
     Full Idea: Whether a property is 'expressible' in a given theory depends on the richness of the theory's language. Whether the property can be 'captured' (or 'represented') by the theory depends on the richness of the axioms and proof system.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 04.7)
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / a. Numbers
For primes we write (x not= 1 ∧ ∀u∀v(u x v = x → (u = 1 ∨ v = 1))) [Smith,P]
     Full Idea: For prime numbers we write (x not= 1 ∧ ∀u∀v(u x v = x → (u = 1 ∨ v = 1))). That is, the only way to multiply two numbers and a get a prime is if one of them is 1.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 04.5)
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
The reals contain the naturals, but the theory of reals doesn't contain the theory of naturals [Smith,P]
     Full Idea: It has been proved (by Tarski) that the real numbers R is a complete theory. But this means that while the real numbers contain the natural numbers, the pure theory of real numbers doesn't contain the theory of natural numbers.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 18.2)
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / f. Arithmetic
The truths of arithmetic are just true equations and their universally quantified versions [Smith,P]
     Full Idea: The truths of arithmetic are just the true equations involving particular numbers, and universally quantified versions of such equations.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 27.7)
     A reaction: Must each equation be universally quantified? Why can't we just universally quantify over the whole system?
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
All numbers are related to zero by the ancestral of the successor relation [Smith,P]
     Full Idea: All numbers are related to zero by the ancestral of the successor relation.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 23.5)
     A reaction: The successor relation only ties a number to the previous one, not to the whole series. Ancestrals are a higher level of abstraction.
The number of Fs is the 'successor' of the Gs if there is a single F that isn't G [Smith,P]
     Full Idea: The number of Fs is the 'successor' of the number of Gs if there is an object which is an F, and the remaining things that are F but not identical to the object are equinumerous with the Gs.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 14.1)
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / b. Baby arithmetic
Baby arithmetic covers addition and multiplication, but no general facts about numbers [Smith,P]
     Full Idea: Baby Arithmetic 'knows' the addition of particular numbers and multiplication, but can't express general facts about numbers, because it lacks quantification. It has a constant '0', a function 'S', and functions '+' and 'x', and identity and negation.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 08.1)
Baby Arithmetic is complete, but not very expressive [Smith,P]
     Full Idea: Baby Arithmetic is negation complete, so it can prove every claim (or its negation) that it can express, but it is expressively extremely impoverished.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 08.3)
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / c. Robinson arithmetic
Robinson Arithmetic (Q) is not negation complete [Smith,P]
     Full Idea: Robinson Arithmetic (Q) is not negation complete
     From: Peter Smith (Intro to Gödel's Theorems [2007], 08.4)
Robinson Arithmetic 'Q' has basic axioms, quantifiers and first-order logic [Smith,P]
     Full Idea: We can beef up Baby Arithmetic into Robinson Arithmetic (referred to as 'Q'), by restoring quantifiers and variables. It has seven generalised axioms, plus standard first-order logic.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 08.3)
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
Natural numbers have zero, unique successors, unending, no circling back, and no strays [Smith,P]
     Full Idea: The sequence of natural numbers starts from zero, and each number has just one immediate successor; the sequence continues without end, never circling back on itself, and there are no 'stray' numbers, lurking outside the sequence.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 01.1)
     A reaction: These are the characteristics of the natural numbers which have to be pinned down by any axiom system, such as Peano's, or any more modern axiomatic structures. We are in the territory of Gödel's theorems.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
The logic of arithmetic must quantify over properties of numbers to handle induction [Smith,P]
     Full Idea: If the logic of arithmetic doesn't have second-order quantifiers to range over properties of numbers, how can it handle induction?
     From: Peter Smith (Intro to Gödel's Theorems [2007], 10.1)
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Multiplication only generates incompleteness if combined with addition and successor [Smith,P]
     Full Idea: Multiplication in itself isn't is intractable. In 1929 Skolem showed a complete theory for a first-order language with multiplication but lacking addition (or successor). Multiplication together with addition and successor produces incompleteness.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 10.7 n8)
Incompleteness results in arithmetic from combining addition and successor with multiplication [Smith,P]
     Full Idea: Putting multiplication together with addition and successor in the language of arithmetic produces incompleteness.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 10.7)
     A reaction: His 'Baby Arithmetic' has all three and is complete, but lacks quantification (p.51)
8. Modes of Existence / A. Relations / 4. Formal Relations / c. Ancestral relation
The 'ancestral' of a relation is a new relation which creates a long chain of the original relation [Smith,P]
     Full Idea: The 'ancestral' of a relation is that relation which holds when there is an indefinitely long chain of things having the initial relation.
     From: Peter Smith (Intro to Gödel's Theorems [2007], 23.5)
     A reaction: The standard example is spotting the relation 'ancestor' from the receding relation 'parent'. This is a sort of abstraction derived from a relation which is not equivalent (parenthood being transitive but not reflexive). The idea originated with Frege.
13. Knowledge Criteria / C. External Justification / 5. Controlling Beliefs
Control of belief is possible if you know truth conditions and what causes beliefs [Fodor]
     Full Idea: Premeditated cognitive management is possible if knowing the contents of one's thoughts would tell you what would make them true and what would cause you to have them.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: I love the idea of 'cognitive management'. Since belief is fairly involuntary, I subject myself to the newspapers, books, TV and conversation which will create the style of beliefs to which I aspire. Why?
14. Science / A. Basis of Science / 3. Experiment
Participation in an experiment requires agreement about what the outcome will mean [Fodor]
     Full Idea: To be in the audience for an experiment you have to believe what the experimenter believes about what the outcome would mean, but not necessarily what the outcome will be.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
An experiment is a deliberate version of what informal thinking does all the time [Fodor]
     Full Idea: Experimentation is an occasional and more or less self-conscious exercise in what informal thinking does all the time without thinking about it.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
We can deliberately cause ourselves to have true thoughts - hence the value of experiments [Fodor]
     Full Idea: A creature that knows what makes its thoughts true and what would cause it to have them, could therefore cause itself to have true thoughts. …This would explain why experimentation is so close to the heart of our cognitive style.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
Interrogation and experiment submit us to having beliefs caused [Fodor]
     Full Idea: You can put yourself into a situation where you may be caused to believe that P. Putting a question to someone who is in the know is one species of this behaviour, and putting a question to Nature (an experiment) is another.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
14. Science / B. Scientific Theories / 1. Scientific Theory
Theories are links in the causal chain between the environment and our beliefs [Fodor]
     Full Idea: Theories function as links in the causal chains that run from environmental outcomes to the beliefs that they cause the inquirer to have.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
15. Nature of Minds / A. Nature of Mind / 1. Mind / e. Questions about mind
I say psychology is intentional, semantics is informational, and thinking is computation [Fodor]
     Full Idea: I hold that psychological laws are intentional, that semantics is purely informational, and that thinking is computation (and that it is possible to hold all of these assumptions at once).
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: When he puts it baldly like that, it doesn't sound terribly persuasive. Thinking is 'computation'? Raw experience is irrelevant? What is it 'like' to spot an interesting connection between two propositions or concepts? It's not like adding 7 and 5.
15. Nature of Minds / B. Features of Minds / 1. Consciousness / f. Higher-order thought
We are probably the only creatures that can think about our own thoughts [Fodor]
     Full Idea: I think it is likely that we are the only creatures that can think about the contents of our thoughts.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: I think this is a major idea. If you ask me the traditional question - what is the essential difference between us and other animals? - this is my answer (not language, or reason). We are the metathinkers.
17. Mind and Body / A. Mind-Body Dualism / 2. Interactionism
Cartesians consider interaction to be a miracle [Fodor]
     Full Idea: The Cartesian view is that the interaction problem does arise, but is unsolvable because interaction is miraculous.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: A rather unsympathetic statement of the position. Cartesians might think that God could explain to us how interaction works. Cartesians are not mysterians, I think, but they see no sign of any theory of interaction.
Semantics v syntax is the interaction problem all over again [Fodor]
     Full Idea: The question how mental representations could be both semantic, like propositions, and causal, like rocks, trees, and neural firings, is arguably just the interaction problem all over again.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: Interesting way of presenting the problem. If you seem to be confronting the interaction problem, you have probably drifted into a bogus dualist way of thinking. Retreat, and reformulate you questions and conceptual apparatus, till the question vanishes.
17. Mind and Body / E. Mind as Physical / 1. Physical Mind
Type physicalism equates mental kinds with physical kinds [Fodor]
     Full Idea: Type physicalism is, roughly, the doctrine that psychological kinds are identical to neurological kinds.
     From: Jerry A. Fodor (The Elm and the Expert [1993], App A n.1)
     A reaction: This gets my general support, leaving open the nature of 'kinds'. Presumably the identity is strict, as in 'Hesperus is identical to Phosphorus'. It seems unlikely that if you and I think the 'same' thought, that we have strictly identical brain states.
17. Mind and Body / E. Mind as Physical / 4. Connectionism
Hume has no theory of the co-ordination of the mind [Fodor]
     Full Idea: What Hume didn't see was that the causal and representational properties of mental symbols have somehow to be coordinated if the coherence of mental life is to be accounted for.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: Certainly the idea that it all somehow becomes magic at the point where the brain represents the world is incoherent - but it is a bit magical. How can the whole of my garden be in my brain? Weird.
18. Thought / A. Modes of Thought / 2. Propositional Attitudes
Propositional attitudes are propositions presented in a certain way [Fodor]
     Full Idea: Propositional attitudes are really three-place relations, between a creature, a proposition, and a mode of presentation (which are sentences of Mentalese).
     From: Jerry A. Fodor (The Elm and the Expert [1993], §2.II)
     A reaction: I'm not sure about 'really'! Why do we need a creature? Isn't 'hoping it will rain' a propositional attitude which some creature may or may not have? Fodor wants it to be physical, but it's abstract?
18. Thought / A. Modes of Thought / 5. Rationality / a. Rationality
Rationality has mental properties - autonomy, productivity, experiment [Fodor]
     Full Idea: Mentalism isn't gratuitous; you need it to explain rationality. Mental causation buys you behaviours that are unlike reflexes in at least three ways: they're autonomous, they're productive, and they're experimental.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: He makes his three ways sound all-or-nothing, which is (I believe) the single biggest danger when thinking about the mind. "Either you are conscious, or you are not..."
18. Thought / C. Content / 5. Twin Earth
XYZ (Twin Earth 'water') is an impossibility [Fodor]
     Full Idea: There isn't any XYZ, and there couldn't be any, and so we don't have to worry about it.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §2.I)
     A reaction: Jadeite and Nephrite are real enough, which are virtually indistinguishable variants of jade. You just need Twin Jewellers instead of Twin Earths. We could build them, and employ twins to work there.
18. Thought / C. Content / 6. Broad Content
Truth conditions require a broad concept of content [Fodor]
     Full Idea: We need the idea of broad content to make sense of the fact that thoughts have the truth-conditions that they do.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §2.II)
     A reaction: There seems to be (as Dummett points out) a potential circularity here, as you can hardly know the truth-conditions of something if you don't already know its content.
18. Thought / C. Content / 7. Narrow Content
Concepts aren't linked to stuff; they are what is caused by stuff [Fodor]
     Full Idea: If the words of 'Swamp Man' (spontaneously created, with concepts) are about XYZ on Twin Earth, it is not because he's causally connected to the stuff, but because XYZ would cause his 'water' tokens (in the absence of H2O).
     From: Jerry A. Fodor (The Elm and the Expert [1993], App B)
     A reaction: The sight of the Eiffel tower causes my 'France' tokens, so is my word "France" about the Eiffel Tower? What would cause my 'nothing' tokens?
18. Thought / C. Content / 10. Causal Semantics
Knowing the cause of a thought is almost knowing its content [Fodor]
     Full Idea: If you know the content of a thought, you know quite a lot about what would cause you to have it.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: I'm not sure where this fits into the great jigsaw of the mind, but it strikes me as an acute and important observation. The truth of a thought is not essential to make you have it. Ask Othello.
18. Thought / C. Content / 12. Informational Semantics
Is content basically information, fixed externally? [Fodor]
     Full Idea: I assume intentional content reduces (in some way) to information. …The content of a thought depends on its external relations; on the way that the thought is related to the world, not the way that it is related to other thoughts.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §1.2)
     A reaction: Does this make Fodor a 'weak' functionalist? The 'strong' version would say a thought is merely a location in a flow diagram, but Fodor's 'mentalism' includes a further 'content' in each diagram box.
18. Thought / D. Concepts / 3. Ontology of Concepts / b. Concepts as abilities
In the information view, concepts are potentials for making distinctions [Fodor]
     Full Idea: Semantics, according to the informational view, is mostly about counterfactuals; what counts for the identity of my concepts is not what I do distinguish but what I could distinguish if I cared to (even using instruments and experts).
     From: Jerry A. Fodor (The Elm and the Expert [1993], §2.I)
     A reaction: We all differ in our discriminations (and awareness of expertise), so our concepts would differ, which is bad news for communication (see Idea 223). The view has some plausibility, though.
19. Language / A. Nature of Meaning / 1. Meaning
Semantic externalism says the concept 'elm' needs no further beliefs or inferences [Fodor]
     Full Idea: It is the essence of semantic externalism that there is nothing that you have to believe, there are no inferences that you have to accept, to have the concept 'elm'.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §2.I)
     A reaction: [REMINDER: broad content is filed in 18.C.7, under 'Thought' rather than under language. That is because I am a philospher of thought, rather than of language.
If meaning is information, that establishes the causal link between the state of the world and our beliefs [Fodor]
     Full Idea: It is the causal connection between the state of the world and the contents of beliefs that the reduction of meaning to information is designed to insure.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: I'm not clear why characterising the contents of a belief in terms of its information has to amount to a 'reduction'. A cup of tea isn't reduced to tea. Connections imply duality.
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
To know the content of a thought is to know what would make it true [Fodor]
     Full Idea: If you know the content of a thought, you thereby know what would make the thought true.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: The truthmaker might by physically impossible, and careful thought might show it to be contradictory - but that wouldn't destroy the meaning.
19. Language / A. Nature of Meaning / 7. Meaning Holism / b. Language holism
For holists no two thoughts are ever quite the same, which destroys faith in meaning [Fodor]
     Full Idea: If what you are thinking depends on all of what you believe, then nobody ever thinks the same thing twice. …That is why so many semantic holists (Quine, Putnam, Rorty, Churchland, probably Wittgenstein) end up being semantic eliminativists.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §1.2b)
     A reaction: If linguistic holism is nonsense, this is easily settled. What I say about breakfast is not changed by reading some Gibbon yesterday.
19. Language / B. Reference / 4. Descriptive Reference / a. Sense and reference
It is claimed that reference doesn't fix sense (Jocasta), and sense doesn't fix reference (Twin Earth) [Fodor]
     Full Idea: The standard view is that Frege cases [knowing Jocasta but not mother] show that reference doesn't determine sense, and Twin cases [knowing water but not H2O] show that sense doesn't determine reference.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §1.3)
     A reaction: How about 'references don't contain much information', and 'descriptions may not fix what they are referring to'? Simple really.
19. Language / C. Assigning Meanings / 2. Semantics
Broad semantics holds that the basic semantic properties are truth and denotation [Fodor]
     Full Idea: Broad semantic theories generally hold that the basic semantic properties of thoughts are truth and denotation.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §1.2b)
     A reaction: I think truth and denotation are the basic semantic properties, but I am dubious about whole-hearted broad semantic theories, so I seem to have gone horribly wrong somewhere.
19. Language / C. Assigning Meanings / 6. Truth-Conditions Semantics
Externalist semantics are necessary to connect the contents of beliefs with how the world is [Fodor]
     Full Idea: You need an externalist semantics to explain why the contents of beliefs should have anything to do with how the world is.
     From: Jerry A. Fodor (The Elm and the Expert [1993], §4)
     A reaction: Since externalist semantics only emerged in the 1970s, that implies that no previous theory had any notion that language had some connection to how the world is. Eh?