Combining Philosophers

All the ideas for Charles Parsons, Michael Potter and Laurence Bonjour

unexpand these ideas     |    start again     |     specify just one area for these philosophers


80 ideas

1. Philosophy / D. Nature of Philosophy / 1. Philosophy
Philosophy is a priori if it is anything [Bonjour]
     Full Idea: My conviction is that philosophy is a priori if it is anything.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], Pref)
     A reaction: How about knowledge of a posteriori necessities, such as the length of a metre, known by observation of the standard metre in Paris?
2. Reason / A. Nature of Reason / 3. Pure Reason
Perceiving necessary connections is the essence of reasoning [Bonjour]
     Full Idea: If one never in fact grasps any necessary connections between anything, it is hard to see what reasoning could possible amount to.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §4.3)
2. Reason / A. Nature of Reason / 6. Coherence
Coherence can't be validated by appeal to coherence [Bonjour]
     Full Idea: The epistemic authority of coherence cannot itself be established by appeal to coherence.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §3.7 n50)
     A reaction: The standard approach amongs modern philosophers (following, I think, Kripke) is to insist on 'intuition' as basic, despite all its problems. I have no better suggestion.
For any given area, there seem to be a huge number of possible coherent systems of beliefs [Bonjour]
     Full Idea: The 2nd standard objection to coherence is 'alternative coherent systems' - that there will be indefinitely many possible systems of belief in relation to any given subject area, each as internally coherent as the others.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 3.2)
     A reaction: This seems to imply that you could just invent an explanation, as long as it was coherent, but presumably good coherence is highly sensitive to the actual evidence. Bonjour observes that many of these systems would not survive over time.
2. Reason / D. Definition / 8. Impredicative Definition
Impredicative definitions are circular, but fine for picking out, rather than creating something [Potter]
     Full Idea: The circularity in a definition where the property being defined is used in the definition is now known as 'impredicativity'. ...Some cases ('the tallest man in the room') are unproblematic, as they pick him out, and don't conjure him into existence.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 07 'Impred')
     A reaction: [part summary]
3. Truth / A. Truth Problems / 2. Defining Truth
The Identity Theory says a proposition is true if it coincides with what makes it true [Potter]
     Full Idea: The Identity Theory of truth says a proposition is true just in case it coincides with what makes it true.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 23 'Abs')
     A reaction: The obvious question is how 'there are trees in the wood' can somehow 'coincide with' or 'be identical to' the situation outside my window. The theory is sort of right, but we will never define the relationship, which is no better than 'corresponds'.
3. Truth / C. Correspondence Truth / 1. Correspondence Truth
It has been unfortunate that externalism about truth is equated with correspondence [Potter]
     Full Idea: There has been an unfortunate tendency in the secondary literature to equate externalism about truth with the correspondence theory.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 65 'Truth')
     A reaction: Quite helpful to distinguish internalist from externalist theories of truth. It is certainly the case that robust externalist views of truth have unfortunately been discredited merely because the correspondence account is inadequate.
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
Modal logic is not an extensional language [Parsons,C]
     Full Idea: Modal logic is not an extensional language.
     From: Charles Parsons (A Plea for Substitutional Quantification [1971], p.159 n8)
     A reaction: [I record this for investigation. Possible worlds seem to contain objects]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Set theory's three roles: taming the infinite, subject-matter of mathematics, and modes of reasoning [Potter]
     Full Idea: Set theory has three roles: as a means of taming the infinite, as a supplier of the subject-matter of mathematics, and as a source of its modes of reasoning.
     From: Michael Potter (Set Theory and Its Philosophy [2004], Intro 1)
     A reaction: These all seem to be connected with mathematics, but there is also ontological interest in set theory. Potter emphasises that his second role does not entail a commitment to sets 'being' numbers.
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
Usually the only reason given for accepting the empty set is convenience [Potter]
     Full Idea: It is rare to find any direct reason given for believing that the empty set exists, except for variants of Dedekind's argument from convenience.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 04.3)
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
Infinity: There is at least one limit level [Potter]
     Full Idea: Axiom of Infinity: There is at least one limit level.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 04.9)
     A reaction: A 'limit ordinal' is one which has successors, but no predecessors. The axiom just says there is at least one infinity.
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The old problems with the axiom of choice are probably better ascribed to the law of excluded middle [Parsons,C]
     Full Idea: The difficulties historically attributed to the axiom of choice are probably better ascribed to the law of excluded middle.
     From: Charles Parsons (Review of Tait 'Provenance of Pure Reason' [2009], §2)
     A reaction: The law of excluded middle was a target for the intuitionists, so presumably the debate went off in that direction.
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / e. Iterative sets
Nowadays we derive our conception of collections from the dependence between them [Potter]
     Full Idea: It is only quite recently that the idea has emerged of deriving our conception of collections from a relation of dependence between them.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 03.2)
     A reaction: This is the 'iterative' view of sets, which he traces back to Gödel's 'What is Cantor's Continuum Problem?'
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / f. Limitation of Size
The 'limitation of size' principles say whether properties collectivise depends on the number of objects [Potter]
     Full Idea: We group under the heading 'limitation of size' those principles which classify properties as collectivizing or not according to how many objects there are with the property.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 13.5)
     A reaction: The idea was floated by Cantor, toyed with by Russell (1906), and advocated by von Neumann. The thought is simply that paradoxes start to appear when sets become enormous.
4. Formal Logic / G. Formal Mereology / 1. Mereology
Mereology elides the distinction between the cards in a pack and the suits [Potter]
     Full Idea: Mereology tends to elide the distinction between the cards in a pack and the suits.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 02.1)
     A reaction: The example is a favourite of Frege's. Potter is giving a reason why mathematicians opted for set theory. I'm not clear, though, why a pack cannot have either 4 parts or 52 parts. Parts can 'fall under a concept' (such as 'legs'). I'm puzzled.
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
We can formalize second-order formation rules, but not inference rules [Potter]
     Full Idea: In second-order logic only the formation rules are completely formalizable, not the inference rules.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 01.2)
     A reaction: He cites Gödel's First Incompleteness theorem for this.
5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
Frege's sign |--- meant judgements, but the modern |- turnstile means inference, with intecedents [Potter]
     Full Idea: Natural deduction systems generally depend on conditional proof, but for Frege everything is asserted unconditionally. The modern turnstile |- is allowed to have antecedents, and hence to represent inference rather than Frege's judgement sign |---.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 03 'Axioms')
     A reaction: [compressed] Shockingly, Frege's approach seems more psychological than the modern approach. I would say that the whole point of logic is that it has to be conditional, because the truth of the antecedents is irrelevant.
5. Theory of Logic / C. Ontology of Logic / 3. If-Thenism
Deductivism can't explain how the world supports unconditional conclusions [Potter]
     Full Idea: Deductivism is a good account of large parts of mathematics, but stumbles where mathematics is directly applicable to the world. It fails to explain how we detach the antecedent so as to arrive at unconditional conclusions.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 12 'Deduc')
     A reaction: I suppose the reply would be that we have designed deductive structures which fit our understanding of reality - so it is all deductive, but selected pragmatically.
5. Theory of Logic / G. Quantification / 4. Substitutional Quantification
Substitutional existential quantifier may explain the existence of linguistic entities [Parsons,C]
     Full Idea: I argue (against Quine) that the existential quantifier substitutionally interpreted has a genuine claim to express a concept of existence, which may give the best account of linguistic abstract entities such as propositions, attributes, and classes.
     From: Charles Parsons (A Plea for Substitutional Quantification [1971], p.156)
     A reaction: Intuitively I have my doubts about this, since the whole thing sounds like a verbal and conventional game, rather than anything with a proper ontology. Ruth Marcus and Quine disagree over this one.
On the substitutional interpretation, '(∃x) Fx' is true iff a closed term 't' makes Ft true [Parsons,C]
     Full Idea: For the substitutional interpretation of quantifiers, a sentence of the form '(∃x) Fx' is true iff there is some closed term 't' of the language such that 'Ft' is true. For the objectual interpretation some object x must exist such that Fx is true.
     From: Charles Parsons (A Plea for Substitutional Quantification [1971], p.156)
     A reaction: How could you decide if it was true for 't' if you didn't know what object 't' referred to?
5. Theory of Logic / H. Proof Systems / 3. Proof from Assumptions
Supposing axioms (rather than accepting them) give truths, but they are conditional [Potter]
     Full Idea: A 'supposition' axiomatic theory is as concerned with truth as a 'realist' one (with undefined terms), but the truths are conditional. Satisfying the axioms is satisfying the theorem. This is if-thenism, or implicationism, or eliminative structuralism.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 01.1)
     A reaction: Aha! I had failed to make the connection between if-thenism and eliminative structuralism (of which I am rather fond). I think I am an if-thenist (not about all truth, but about provable truth).
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
Modern logical truths are true under all interpretations of the non-logical words [Potter]
     Full Idea: In the modern definition, a 'logical truth' is true under every interpretation of the non-logical words it contains.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 19 'Frege's')
     A reaction: What if the non-logical words are nonsense, or are used inconsistently ('good'), or ambiguously ('bank'), or vaguely ('bald'), or with unsure reference ('the greatest philosopher' becomes 'Bentham')? What qualifies as an 'interpretation'?
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / e. The Lottery paradox
The Lottery Paradox says each ticket is likely to lose, so there probably won't be a winner [Bonjour, by PG]
     Full Idea: The Lottery Paradox says that for 100 tickets and one winner, each ticket has a .99 likelihood of defeat, so they are all likely to lose, so there is unlikely to be a winner.
     From: report of Laurence Bonjour (Externalist Theories of Empirical Knowledge [1980], §5) by PG - Db (ideas)
     A reaction: The problem seems to be viewing each ticket in isolation. If I buy two tickets, I increase my chances of winning.
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / c. Counting procedure
Parsons says counting is tagging as first, second, third..., and converting the last to a cardinal [Parsons,C, by Heck]
     Full Idea: In Parsons's demonstrative model of counting, '1' means the first, and counting says 'the first, the second, the third', where one is supposed to 'tag' each object exactly once, and report how many by converting the last ordinal into a cardinal.
     From: report of Charles Parsons (Frege's Theory of Numbers [1965]) by Richard G. Heck - Cardinality, Counting and Equinumerosity 3
     A reaction: This sounds good. Counting seems to rely on that fact that numbers can be both ordinals and cardinals. You don't 'convert' at the end, though, because all the way you mean 'this cardinality in this order'.
If set theory didn't found mathematics, it is still needed to count infinite sets [Potter]
     Full Idea: Even if set theory's role as a foundation for mathematics turned out to be wholly illusory, it would earn its keep through the calculus it provides for counting infinite sets.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 03.8)
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
It is remarkable that all natural number arithmetic derives from just the Peano Axioms [Potter]
     Full Idea: It is a remarkable fact that all the arithmetical properties of the natural numbers can be derived from such a small number of assumptions (as the Peano Axioms).
     From: Michael Potter (Set Theory and Its Philosophy [2004], 05.2)
     A reaction: If one were to defend essentialism about arithmetic, this would be grist to their mill. I'm just saying.
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / c. Against mathematical empiricism
General principles can be obvious in mathematics, but bold speculations in empirical science [Parsons,C]
     Full Idea: The existence of very general principles in mathematics are universally regarded as obvious, where on an empiricist view one would expect them to be bold hypotheses, about which a prudent scientist would maintain reserve.
     From: Charles Parsons (Mathematical Intuition [1980], p.152), quoted by Penelope Maddy - Naturalism in Mathematics
     A reaction: This is mainly aimed at Quine's and Putnam's indispensability (to science) argument about mathematics.
6. Mathematics / C. Sources of Mathematics / 7. Formalism
The formalist defence against Gödel is to reject his metalinguistic concept of truth [Potter]
     Full Idea: Gödel's theorem does not refute formalism outright, because the committed formalist need not recognise the metalinguistic notion of truth to which the theorem appeals.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 45 'Log')
     A reaction: The theorem was prior to Tarski's account of truth. Potter says Gödel avoided explicit mention of truth because of this problem. In general Gödel showed that there are truths outside the formal system (which is all provable).
6. Mathematics / C. Sources of Mathematics / 8. Finitism
If functions are transfinite objects, finitists can have no conception of them [Parsons,C]
     Full Idea: The finitist may have no conception of function, because functions are transfinite objects.
     From: Charles Parsons (Review of Tait 'Provenance of Pure Reason' [2009], §4)
     A reaction: He is offering a view of Tait's. Above my pay scale, but it sounds like a powerful objection to the finitist view. Maybe there is a finitist account of functions that could be given?
6. Mathematics / C. Sources of Mathematics / 9. Fictional Mathematics
Why is fictional arithmetic applicable to the real world? [Potter]
     Full Idea: Fictionalists struggle to explain why arithmetic is applicable to the real world in a way that other stories are not.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 21 'Math')
     A reaction: We know why some novels are realistic and others just the opposite. If a novel aimed to 'model' the real world it would be even closer to it. Fictionalists must explain why some fictions are useful.
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
If 'concrete' is the negative of 'abstract', that means desires and hallucinations are concrete [Potter]
     Full Idea: The word 'concrete' is often used as the negative of 'abstract', with the slightly odd consequence that desires and hallucinations are thereby classified as concrete.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 12 'Numb')
     A reaction: There is also the even more baffling usage of 'abstract' for the most highly generalised mathematics, leaving lower levels as 'concrete'. I favour the use of 'generalised' wherever possible, rather than 'abstract'.
7. Existence / D. Theories of Reality / 11. Ontological Commitment / e. Ontological commitment problems
If a mathematical structure is rejected from a physical theory, it retains its mathematical status [Parsons,C]
     Full Idea: If experience shows that some aspect of the physical world fails to instantiate a certain mathematical structure, one will modify the theory by sustituting a different structure, while the original structure doesn't lose its status as part of mathematics.
     From: Charles Parsons (Review of Tait 'Provenance of Pure Reason' [2009], §2)
     A reaction: This seems to be a beautifully simple and powerful objection to the Quinean idea that mathematics somehow only gets its authority from physics. It looked like a daft view to begin with, of course.
8. Modes of Existence / A. Relations / 4. Formal Relations / a. Types of relation
A relation is a set consisting entirely of ordered pairs [Potter]
     Full Idea: A set is called a 'relation' if every element of it is an ordered pair.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 04.7)
     A reaction: This is the modern extensional view of relations. For 'to the left of', you just list all the things that are to the left, with the things they are to the left of. But just listing the ordered pairs won't necessarily reveal how they are related.
8. Modes of Existence / A. Relations / 4. Formal Relations / c. Ancestral relation
'Greater than', which is the ancestral of 'successor', strictly orders the natural numbers [Potter]
     Full Idea: From the successor function we can deduce its ancestral, the 'greater than' relation, which is a strict total ordering of the natural numbers. (Frege did not mention this, but Dedekind worked it out, when expounding definition by recursion).
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 07 'Def')
     A reaction: [compressed]
9. Objects / B. Unity of Objects / 2. Substance / b. Need for substance
If dependence is well-founded, with no infinite backward chains, this implies substances [Potter]
     Full Idea: The argument that the relation of dependence is well-founded ...is a version of the classical arguments for substance. ..Any conceptual scheme which genuinely represents a world cannot contain infinite backward chains of meaning.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 03.3)
     A reaction: Thus the iterative conception of set may imply a notion of substance, and Barwise's radical attempt to ditch the Axiom of Foundation (Idea 13039) was a radical attempt to get rid of 'substances'. Potter cites Wittgenstein as a fan of substances here.
9. Objects / C. Structure of Objects / 8. Parts of Objects / b. Sums of parts
Collections have fixed members, but fusions can be carved in innumerable ways [Potter]
     Full Idea: A collection has a determinate number of members, whereas a fusion may be carved up into parts in various equally valid (although perhaps not equally interesting) ways.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 02.1)
     A reaction: This seems to sum up both the attraction and the weakness of mereology. If you doubt the natural identity of so-called 'objects', then maybe classical mereology is the way to go.
10. Modality / A. Necessity / 1. Types of Modality
Priority is a modality, arising from collections and members [Potter]
     Full Idea: We must conclude that priority is a modality distinct from that of time or necessity, a modality arising in some way out of the manner in which a collection is constituted from its members.
     From: Michael Potter (Set Theory and Its Philosophy [2004], 03.3)
     A reaction: He is referring to the 'iterative' view of sets, and cites Aristotle 'Metaphysics' 1019a1-4 as background.
10. Modality / B. Possibility / 1. Possibility
The concept of possibility is prior to that of necessity [Bonjour]
     Full Idea: While necessity and possibility are interdefinable concepts, it is the idea of a possible world or situation which is intuitively primary.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §1.3)
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
A material conditional cannot capture counterfactual reasoning [Potter]
     Full Idea: What the material conditional most significantly fails to capture is counterfactual reasoning.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 04 'Sem')
     A reaction: The point is that counterfactuals say 'if P were the case (which it isn't), then Q'. But that means P is false, and in the material conditional everything follows from a falsehood. A reinterpretation of the conditional might embrace counterfactuals.
11. Knowledge Aims / A. Knowledge / 1. Knowledge
The concept of knowledge is so confused that it is best avoided [Bonjour]
     Full Idea: The concept of knowledge is seriously problematic in more than one way, and is best avoided as far as possible in sober epistemological discussion.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 1.5)
     A reaction: Two sorts of states seem to be conflated: one where an animal has a true belief caused by an environmental event, and the other where a scholar pores over books and experiments to arrive at a hard-won truth. I say only the second is 'knowledge'.
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
It is hard to give the concept of 'self-evident' a clear and defensible characterization [Bonjour]
     Full Idea: Foundationalists find it difficult to attach a clear and defensible content to the idea that basic beliefs that are characterized as 'self-justified' or 'self-evident'.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 1.4)
     A reaction: A little surprising from a fan of a priori foundations, especially given that 'self-evident' is common usage, and not just philosophers' jargon. I think we can talk of self-evidence without a precise definition. We talk of an 'ocean' without trouble.
12. Knowledge Sources / B. Perception / 8. Adverbial Theory
The adverbial account will still be needed when a mind apprehends its sense-data [Bonjour]
     Full Idea: The adverbial account of the content of experience is almost certainly correct, because no account can be given of the relation between sense-data and the apprehending mind that is independent of the adverbial theory.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 5.1 n3)
     A reaction: This boils down to the usual objection to sense-data, which is 'cut out the middle man'. Bonjour is right that at some point the mind has finally to experience whatever is coming in, and it must experience it in a particular way.
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Our rules of thought can only be judged by pure rational insight [Bonjour]
     Full Idea: Criteria or rules do not somehow apply to themselves. They must be judged by the sort of rational insight or intuition that the rationalist is advocating.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §5.2)
Moderate rationalists believe in fallible a priori justification [Bonjour]
     Full Idea: Moderate rationalism preserves a priori justification, but rejects the idea that it is infallible.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §4.1)
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / a. Foundationalism
Externalist theories of knowledge are one species of foundationalism [Bonjour]
     Full Idea: Externalist theories of knowledge are one species of foundationalism.
     From: Laurence Bonjour (Externalist Theories of Empirical Knowledge [1980], Intro)
     A reaction: I don't see why there shouldn't be a phenomenalist, anti-realist version of externalism, which just has 'starting points' instead of a serious commitment to foundations.
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
The big problem for foundationalism is to explain how basic beliefs are possible [Bonjour]
     Full Idea: The fundamental question that must be answered by any acceptable version of foundationalism is: how are basic beliefs possible?
     From: Laurence Bonjour (Externalist Theories of Empirical Knowledge [1980], §I)
     A reaction: This question seems to be asking for a justification for basic beliefs, which smacks of 'Who made God?' Look, basic beliefs are just basic, right?
Conscious states have built-in awareness of content, so we know if a conceptual description of it is correct [Bonjour]
     Full Idea: If we describe a non-conceptual conscious state, we are aware of its character via the constitutive or 'built-in' awareness of content without need for a conceptual description, and so recognise that a conceptually formulated belief about it is correct.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 4.3)
     A reaction: This is Bonjour working very hard to find an account of primitive sense experiences which will enable them to function as 'basic beliefs' for foundations, without being too thin to do anything, or too thick to be basic. I'm not convinced.
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / d. Rational foundations
A priori justification requires understanding but no experience [Bonjour]
     Full Idea: A proposition will count as being justified a priori as long as no appeal to experience is needed for the proposition to be justified - once it is understood.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §1.2)
     A reaction: Could you 'understand' that a square cannot be circular without appeal to experience? I'm losing faith in the pure a priori.
You can't explain away a priori justification as analyticity, and you can't totally give it up [Bonjour]
     Full Idea: Moderate empiricists try unsuccessfully to explain a priori justification by means of analyticity, and radical empiricist attempts to dispense with a priori justification end in nearly total scepticism.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §4.1)
     A reaction: My working theory is neither of the above. Because we can abstract from the physical world, we can directly see/experience generalised (and even necessary) truths about it.
A priori justification can vary in degree [Bonjour]
     Full Idea: A priori justification can vary in degree.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §4.5)
     A reaction: This idea, which I trace back at least to Russell, seems to me one of breakthrough ideas in modern thought. It means that a priori knowledge can be reconnected with a posteriori knowledge.
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / e. Pro-foundations
The main argument for foundationalism is that all other theories involve a regress leading to scepticism [Bonjour]
     Full Idea: The central argument for foundationalism is simply that all other possible outcomes of the regress of justifications lead inexorably to scepticism.
     From: Laurence Bonjour (Externalist Theories of Empirical Knowledge [1980], §I)
     A reaction: If you prefer coherence to foundations, you need the security of reason to assess the coherence (which seems to be an internal foundation!).
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / f. Foundationalism critique
The induction problem blocks any attempted proof of physical statements [Bonjour]
     Full Idea: The attempt to prove physical statements on the basis of sensory evidence is defeated by the problem of induction.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §3.6)
     A reaction: This sounds like a logician's use of the word 'prove', which would be a pretty forlorn hope. Insofar as experience proves anything, fully sensing a chair proves its existence.
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
A coherence theory of justification can combine with a correspondence theory of truth [Bonjour]
     Full Idea: There is no manifest absurdity in combining a coherence theory of justification with a correspondence theory of truth.
     From: Laurence Bonjour (The Structure of Empirical Knowledge [1985], 5.1)
     A reaction: His point is to sharply (and correctly) distinguish coherent justification from a coherence theory of truth. Personally I would recommend talking of a 'robust' theory of truth, without tricky commitment to 'correspondence' between very dissimilar things.
There will always be a vast number of equally coherent but rival systems [Bonjour]
     Full Idea: On any plausible conception of coherence, there will always be many, probably infinitely many, different and incompatible systems of belief which are equally coherent.
     From: Laurence Bonjour (The Structure of Empirical Knowledge [1985], 5.5)
     A reaction: If 'infinitely many' theories are allowed, that blocks the coherentist hope that widening and precisifying the system will narrow down the options and offer some verisimilitude. If we stick to current English expression, that should keep them finite.
Empirical coherence must attribute reliability to spontaneous experience [Bonjour]
     Full Idea: An empirical coherence theory needs, for the beliefs of a cognitive system to be even candidates for empirical justification, that the system must contain laws attributing a high degree of reliability to a variety of spontaneous cognitive beliefs.
     From: Laurence Bonjour (The Structure of Empirical Knowledge [1985], 7.1)
     A reaction: Wanting such a 'law' seems optimistic, and not in the spirit of true coherentism, which can individually evaluate each experiential belief. I'm not sure Bonjour's Observation Requirement is needed, since it is incoherent to neglect observations.
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / b. Pro-coherentism
The best explanation of coherent observations is they are caused by and correspond to reality [Bonjour]
     Full Idea: The best explanation for a stable system of beliefs which rely on observation is that the beliefs are caused by what they depict, and the system roughly corresponds to the independent reality it describes.
     From: Laurence Bonjour (The Structure of Empirical Knowledge [1985], 8.3)
     A reaction: [compressed] Anyone who links best explanation to coherence (and to induction) warms the cockles of my heart. Erik Olson offers a critique, but doesn't convince me. The alternative is to find a better explanation (than reality), or give up.
A well written novel cannot possibly match a real belief system for coherence [Bonjour]
     Full Idea: It is not even minimally plausible that a well written novel ...would have the degree of coherence required to be a serious alternative to anyone's actual system of beliefs.
     From: Laurence Bonjour (The Structure of Empirical Knowledge [1985], 5.5)
     A reaction: This seems correct. 'Bleak House' is wonderfully consistent, but its elements are entirely verbal, and nothing occupies the space between the facts that are described. And Lady Dedlock is not in Debrett. I think this kills a standard objection.
The objection that a negated system is equally coherent assume that coherence is consistency [Bonjour]
     Full Idea: Sometimes it is said that if one has an appropriately coherent system, an alternative system can be produced simply be negating all of the components of the first system. This would only be so if coherence amounted simply to consistency.
     From: Laurence Bonjour (The Structure of Empirical Knowledge [1985], 5.5)
     A reaction: I associate Russell with this original objection to coherentism. I formerly took this to be a serious problem, and am now relieved to see that it clearly isn't.
A coherent system can be justified with initial beliefs lacking all credibility [Bonjour]
     Full Idea: It is simply not necessary in order for [the coherence] view to yield justification to suppose that cognitively spontaneous beliefs have some degree of initial or independent credibility.
     From: Laurence Bonjour (The Structure of Empirical Knowledge [1985], 7.2)
     A reaction: This is thoroughly and rather persuasively criticised by Erik Olson. But he always focuses on the coherence of a 'system' with multiple beliefs. I take the credibility of each individual belief to need coherent assessment against a full background.
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / c. Coherentism critique
My incoherent beliefs about art should not undermine my very coherent beliefs about physics [Bonjour]
     Full Idea: If coherentism is construed as involving the believer's entire body of beliefs, that would imply, most implausibly, that the justification of a belief in one area (physics) could be undermined by serious incoherence in another area (art history).
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 3.1)
     A reaction: Bonjour suggests that a moderated coherentism is needed to avoid this rather serious problem. It is hard to see how a precise specification could be given of 'areas' and 'local coherence'. An idiot about art would inspire little confidence on physics.
Coherence seems to justify empirical beliefs about externals when there is no external input [Bonjour]
     Full Idea: The 1st standard objection to coherence is the 'isolation problem', that contingent apparently-empirical beliefs might be justified in the absence of any informational input from the extra-conceptual world they attempt to describe.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 3.2)
     A reaction: False beliefs can be well justified. In a perfect virtual reality we would believe our experiences precisely because they were so coherent. Messengers from the front line have top priority, but how do you detect infiltrators and liars?
Coherentists must give a reason why coherent justification is likely to lead to the truth [Bonjour]
     Full Idea: The 3rd standard objection to coherence is the demand for a meta-justification for coherence, a reason for thinking that justification on the basis of the coherentist view of justification is in fact likely to lead to believing the truth.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 3.2)
     A reaction: Some coherentists respond by adopting a coherence theory of truth, which strikes me as extremely unwise. There must be an underlying optimistic view, centred on the principle of sufficient reason, that reality itself is coherent. I like Idea 8618.
13. Knowledge Criteria / C. External Justification / 1. External Justification
Extreme externalism says no more justification is required than the truth of the belief [Bonjour]
     Full Idea: The most extreme version of externalism would be one that held that the external condition required for justification is simply the truth of the belief in question.
     From: Laurence Bonjour (Externalist Theories of Empirical Knowledge [1980], §II)
     A reaction: The question is, why should we demand any more than this? The problem case is, traditionally, the lucky guess, but naturalist may say that these just don't occur with any regularity. We only get beliefs right because they are true.
Externalist theories of justification don't require believers to have reasons for their beliefs [Bonjour]
     Full Idea: An externalist theory of epistemic justification or warrant need not involve the possession by the believer of anything like a reason for thinking that their belief is true.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §3.7)
     A reaction: That is the problem with externalism. If the believer does not have a reason, then why would they believe? Externalists are interesting on justification, but daft about belief. Why do I believe I know something, when I can't recall how I learnt it?
13. Knowledge Criteria / C. External Justification / 3. Reliabilism / a. Reliable knowledge
Reliabilists disagree over whether some further requirement is needed to produce knowledge [Bonjour]
     Full Idea: Reliabilist views differ among themselves with regard to whether a belief's being produced in a reliable way is by itself sufficient for epistemic justification or whether there are further requirements that must be satisfied as well.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 2.1)
     A reaction: If 'further requirements' are needed, the crucial question would be which one is trumps when they clash. If the further requirements can correct the reliable source, then it cannot any longer be called 'reliabilism'. It's Further-requirement-ism.
13. Knowledge Criteria / C. External Justification / 3. Reliabilism / b. Anti-reliabilism
External reliability is not enough, if the internal state of the believer is known to be irrational [Bonjour]
     Full Idea: External or objective reliability is not enough to offset subjective irrationality (such as unexplained clairvoyance).
     From: Laurence Bonjour (Externalist Theories of Empirical Knowledge [1980], §IV)
     A reaction: A good argument. Where do animals fit into this? If your clairvoyance kept working, in the end you might concede that you 'knew', even though you were baffled about how you managed it.
If the reliable facts producing a belief are unknown to me, my belief is not rational or responsible [Bonjour]
     Full Idea: How can the fact that a belief is reliably produced make my acceptance of that belief rational and responsible when that fact itself is entirely unavailable to me?
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 2.2)
     A reaction: This question must rival Pollock's proposal (Idea 8815) as the master argument against externalism. Bonjour is assuming that knowledge has to be 'rational and responsible', but clearly externalists take a more lax view of knowledge.
Knowledge from a drunken schoolteacher is from a reliable and unreliable process [Potter]
     Full Idea: Knowledge might result from a reliable and an unreliable process. ...Is something knowledge if you were told it by a drunken schoolteacher?
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 66 'Rel')
     A reaction: Nice example. The listener must decide which process to rely on. But how do you decide that, if not by assessing the likely truth of what you are being told? It could be a bad teacher who is inspired by drink.
13. Knowledge Criteria / C. External Justification / 10. Anti External Justification
Even if there is no obvious irrationality, it may be irrational to base knowledge entirely on external criteria [Bonjour]
     Full Idea: It may be that where there are no positive grounds for a charge of irrationality, the acceptance of a belief with only external justification is still subjectively irrational in a sense that rules out its being epistemologically justified.
     From: Laurence Bonjour (Externalist Theories of Empirical Knowledge [1980], §IV)
     A reaction: A key objection. Surely rational behaviour requires a judgement to be made before a belief is accepted? If you are consistently clairvoyant, you must ask why.
Externalism means we have no reason to believe, which is strong scepticism [Bonjour]
     Full Idea: If externalism is the final story, we have no reason to think that any of our beliefs are true, which amounts to a very strong and intuitively implausible version of scepticism.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §3.7)
     A reaction: A very good point. I may, like a cat, know many things, with good external support, but as soon as I ask sceptical questions, I sink without trace if I lack internal reasons.
14. Science / A. Basis of Science / 5. Anomalies
Anomalies challenge the claim that the basic explanations are actually basic [Bonjour]
     Full Idea: The distinctive significance of anomalies lies in the fact that they undermine the claim of the allegedly basic explanatory principles to be genuinely basic.
     From: Laurence Bonjour (The Structure of Empirical Knowledge [1985], 5.3)
     A reaction: This seems plausible, suggesting that (rather than an anomaly flatly 'falsifying' a theory) an anomaly may just demand a restructuring or reconceptualising of the theory.
14. Science / C. Induction / 2. Aims of Induction
Induction must go beyond the evidence, in order to explain why the evidence occurred [Bonjour]
     Full Idea: Inductive explanations must be conceived of as something stronger than mere Humean constant conjunction; …anything less than this will not explain why the inductive evidence occurred in the first place.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §7.7)
15. Nature of Minds / B. Features of Minds / 1. Consciousness / f. Higher-order thought
If neither the first-level nor the second-level is itself conscious, there seems to be no consciousness present [Bonjour]
     Full Idea: In the higher-order thought theory of consciousness, if the first-order thought is not itself conscious and the second-order thought is not itself conscious, then there seems to be no consciousness of the first-level content present at all.
     From: Laurence Bonjour (A Version of Internalist Foundationalism [2003], 4.2)
     A reaction: A nice basic question. The only plausible answer seems to be that consciousness arises out of the combination of levels. Otherwise one of the levels is redundant, or we are facing a regress.
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
Traditionally there are twelve categories of judgement, in groups of three [Potter]
     Full Idea: The traditional categorisation of judgements (until at least 1800) was as universal, particular or singular; as affirmative, negative or infinite; as categorical, hypothetical or disjunctive; or as problematic, assertoric or apodictic.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 02 'Trans')
     A reaction: Arranging these things in neat groups of three seems to originate with the stoics. Making distinctions like this is very much the job of a philosopher, but arranging them in neat equinumerous groups is intellectual tyranny.
18. Thought / C. Content / 1. Content
All thought represents either properties or indexicals [Bonjour]
     Full Idea: I assume that the contents of thought can be accounted for by appeal to just two general sorts of ingredient - properties (including relations) and indexicals.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §6.7)
     A reaction: I don't accept that relations are a type of properties. Since he does not include objects or substances, I take it that he considers objects to be bundles of properties.
18. Thought / D. Concepts / 3. Ontology of Concepts / c. Fregean concepts
The phrase 'the concept "horse"' can't refer to a concept, because it is saturated [Potter]
     Full Idea: Frege's mirroring principle (that the structure of thoughts mirrors that of language) has the uncomfortable consequence that since the phrase 'the concept "horse"' is saturated, it cannot refer to something unsaturated, which includes concepts.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 16 'Conc')
19. Language / C. Assigning Meanings / 4. Compositionality
Compositionality should rely on the parsing tree, which may contain more than sentence components [Potter]
     Full Idea: Compositionality is best seen as saying the semantic value of a string is explained by the strings lower down its parsing tree. It is unimportant whether a string is always parsed in terms of its own substrings.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 05 'Sem')
     A reaction: That is, the analysis must explain the meaning, but the analysis can contain more than the actual ingredients of the sentence (which would be too strict).
'Direct compositonality' says the components wholly explain a sentence meaning [Potter]
     Full Idea: Some authors urge the strong notion of 'direct compositionality', which requires that the content of a sentence be explained in terms of the contents of the component parts of that very sentence.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 05 'Sem')
     A reaction: The alternative is that meaning is fully explained by an analysis, but that may contain more than the actual components of the sentence.
Compositionality is more welcome in logic than in linguistics (which is more contextual) [Potter]
     Full Idea: The principle of compositionality is more popular among philosophers of logic than of language, because the subtle context-sensitivity or ordinary language makes providing a compositional semantics for it a daunting challenge.
     From: Michael Potter (The Rise of Analytic Philosophy 1879-1930 [2020], 21 'Lang')
     A reaction: Logicians love breaking complex entities down into simple atomic parts. Linguistics tries to pin down something much more elusive.
19. Language / F. Communication / 6. Interpreting Language / b. Indeterminate translation
Indeterminacy of translation is actually indeterminacy of meaning and belief [Bonjour]
     Full Idea: The thesis of the indeterminacy of translation would be better described as the thesis of the indeterminacy of meaning and belief.
     From: Laurence Bonjour (In Defence of Pure Reason [1998], §3.5)
     A reaction: Not necessarily. It is not incoherent to believe that the target people have a coherent and stable system of meaning and belief, but finding its translation indeterminate because it is holistic, and rooted in a way of life.