24 ideas
| 8893 | 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. |
| 13030 | Extensionality: ∀x ∀y (∀z (z ∈ x ↔ z ∈ y) → x = y) [Kunen] |
| Full Idea: Axiom of Extensionality: ∀x ∀y (∀z (z ∈ x ↔ z ∈ y) → x = y). That is, a set is determined by its members. If every z in one set is also in the other set, then the two sets are the same. | |
| From: Kenneth Kunen (Set Theory [1980], §1.5) |
| 13032 | Pairing: ∀x ∀y ∃z (x ∈ z ∧ y ∈ z) [Kunen] |
| Full Idea: Axiom of Pairing: ∀x ∀y ∃z (x ∈ z ∧ y ∈ z). Any pair of entities must form a set. | |
| From: Kenneth Kunen (Set Theory [1980], §1.6) | |
| A reaction: Repeated applications of this can build the hierarchy of sets. |
| 13033 | Union: ∀F ∃A ∀Y ∀x (x ∈ Y ∧ Y ∈ F → x ∈ A) [Kunen] |
| Full Idea: Axiom of Union: ∀F ∃A ∀Y ∀x (x ∈ Y ∧ Y ∈ F → x ∈ A). That is, the union of a set (all the members of the members of the set) must also be a set. | |
| From: Kenneth Kunen (Set Theory [1980], §1.6) |
| 13037 | Infinity: ∃x (0 ∈ x ∧ ∀y ∈ x (S(y) ∈ x) [Kunen] |
| Full Idea: Axiom of Infinity: ∃x (0 ∈ x ∧ ∀y ∈ x (S(y) ∈ x). That is, there is a set which contains zero and all of its successors, hence all the natural numbers. The principal of induction rests on this axiom. | |
| From: Kenneth Kunen (Set Theory [1980], §1.7) |
| 13038 | Power Set: ∀x ∃y ∀z(z ⊂ x → z ∈ y) [Kunen] |
| Full Idea: Power Set Axiom: ∀x ∃y ∀z(z ⊂ x → z ∈ y). That is, there is a set y which contains all of the subsets of a given set. Hence we define P(x) = {z : z ⊂ x}. | |
| From: Kenneth Kunen (Set Theory [1980], §1.10) |
| 13034 | Replacement: ∀x∈A ∃!y φ(x,y) → ∃Y ∀X∈A ∃y∈Y φ(x,y) [Kunen] |
| Full Idea: Axiom of Replacement Scheme: ∀x ∈ A ∃!y φ(x,y) → ∃Y ∀X ∈ A ∃y ∈ Y φ(x,y). That is, any function from a set A will produce another set Y. | |
| From: Kenneth Kunen (Set Theory [1980], §1.6) |
| 13039 | Foundation:∀x(∃y(y∈x) → ∃y(y∈x ∧ ¬∃z(z∈x ∧ z∈y))) [Kunen] |
| Full Idea: Axiom of Foundation: ∀x (∃y(y ∈ x) → ∃y(y ∈ x ∧ ¬∃z(z ∈ x ∧ z ∈ y))). Aka the 'Axiom of Regularity'. Combined with Choice, it means there are no downward infinite chains. | |
| From: Kenneth Kunen (Set Theory [1980], §3.4) |
| 13036 | Choice: ∀A ∃R (R well-orders A) [Kunen] |
| Full Idea: Axiom of Choice: ∀A ∃R (R well-orders A). That is, for every set, there must exist another set which imposes a well-ordering on it. There are many equivalent versions. It is not needed in elementary parts of set theory. | |
| From: Kenneth Kunen (Set Theory [1980], §1.6) |
| 13029 | Set Existence: ∃x (x = x) [Kunen] |
| Full Idea: Axiom of Set Existence: ∃x (x = x). This says our universe is non-void. Under most developments of formal logic, this is derivable from the logical axioms and thus redundant, but we do so for emphasis. | |
| From: Kenneth Kunen (Set Theory [1980], §1.5) |
| 13031 | Comprehension: ∃y ∀x (x ∈ y ↔ x ∈ z ∧ φ) [Kunen] |
| Full Idea: Comprehension Scheme: for each formula φ without y free, the universal closure of this is an axiom: ∃y ∀x (x ∈ y ↔ x ∈ z ∧ φ). That is, there must be a set y if it can be defined by the formula φ. | |
| From: Kenneth Kunen (Set Theory [1980], §1.5) | |
| A reaction: Unrestricted comprehension leads to Russell's paradox, so restricting it in some way (e.g. by the Axiom of Specification) is essential. |
| 13040 | Constructibility: V = L (all sets are constructible) [Kunen] |
| Full Idea: Axiom of Constructability: this is the statement V = L (i.e. ∀x ∃α(x ∈ L(α)). That is, the universe of well-founded von Neumann sets is the same as the universe of sets which are actually constructible. A possible axiom. | |
| From: Kenneth Kunen (Set Theory [1980], §6.3) |
| 8888 | 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'. |
| 8887 | 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. |
| 8897 | 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. |
| 8896 | 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. |
| 8891 | 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. |
| 8892 | 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? |
| 8894 | 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. |
| 8889 | 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. |
| 8890 | 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. |
| 8895 | 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. |
| 7829 | God no more has human perfections than we have animal perfections [Spinoza] |
| Full Idea: To ascribe to God those attributes which make a man perfect would be as wrong as to ascribe to a man the attributes that make perfect an elephant or an ass. | |
| From: Baruch de Spinoza (Letters to Blijenburgh [1665], 1665), quoted by Matthew Stewart - The Courtier and the Heretic Ch.10 | |
| A reaction: This would be a difficulty for Aquinas's Fourth Way (Idea 1432), and one which I think Aquinas might acknowledge, given his desire that we should be humble when trying to comprehend God (Idea 1410). It leaves us struggling to grasp the concept of God. |
| 7830 | A talking triangle would say God is triangular [Spinoza] |
| Full Idea: If a triangle could speak it would say that God is eminently triangular. | |
| From: Baruch de Spinoza (Letters to Blijenburgh [1665], 1665), quoted by Matthew Stewart - The Courtier and the Heretic Ch.10 | |
| A reaction: Spinoza had a rather appealing waspish wit. This nicely dramatises an ancient idea (Idea 407). You can, of course, if you believe in God, infer some of His characteristics from His creation. But then see Hume: Ideas 1439, 6960, 6967, 1440. |