| 11239 | The notion of a priori truth is absent in Aristotle [Aristotle, by Politis] |
| Full Idea: The notion of a priori truth is conspicuously absent in Aristotle. | |
| From: report of Aristotle (works [c.330 BCE]) by Vassilis Politis - Aristotle and the Metaphysics 1.5 | |
| A reaction: Cf. Idea 11240. |
| 20784 | There are non-sensible presentations, which come to us through the intellect [Stoic school, by Diog. Laertius] |
| Full Idea: Stoics say some presentations are sensible, some non-sensible. Those received through the sense organs are sensible; non-sensible are those which come through the intellect, for example, presentations of incorporeals and other things grasped by reason. | |
| From: report of Stoic school (fragments/reports [c.200 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.51 | |
| A reaction: The a priori used to be metaphysics (a world of truths), and in modern times is epistemology (a mode of justification), but here it is just a mode of experience, which is not, it seems, necessarily true. |
| 9156 | Kant's shift of view enables us to see a priority in terms of mental capacity, not truth and propositions [Burge on Kant] |
| Full Idea: Kant's shift in his understanding of apriority from the content of truth and of proof-sequences of propositions to the character of cognitive procedures opens more possibilities for understanding the sources of apriority, in capacities and mental acts. | |
| From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Tyler Burge - Frege on Apriority I | |
| A reaction: [Burge attributes the alternative view to Leibniz and Frege] This harmless-looking thought seems to me right at the heart of what I take to be a discrete cold war going on between logicians and philosophers. Logic is in retreat! |
| 7575 | A priori knowledge is limited to objects of possible experience [Kant, by Jolley] |
| Full Idea: Kant says that a priori knowledge is limited to objects of possible experience, and this is the core thesis of his distinctive doctrine of transcendental idealism. | |
| From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Nicholas Jolley - Leibniz Ch.8 | |
| A reaction: Some people would even challenge this bold claim for a priori knowledge, but this idea shows why Kant was said to have put an end to old fashioned speculative metaphysics. For Kant, a priori knowledge seems to be something like introspection. |
| 12414 | A priori knowledge occurs absolutely independently of all experience [Kant] |
| Full Idea: We will understand by a priori cognitions not those that occur independently of this or that experience, but rather those that occur absolutely independently of all experience. | |
| From: Immanuel Kant (Critique of Pure Reason [1781], B003) | |
| A reaction: Kitcher quotes this, and raises questions about how widely we should understand 'experience', and how strongly we can assert total 'independence'. But then he is attacking the whole idea of a priori knowledge. He modifies Kant's formulation (Idea 12415). |
| 9351 | One sort of a priori knowledge just analyses given concepts, but another ventures further [Kant] |
| Full Idea: Analysis of concepts affords us a multitude of cognitions which are illuminations or clarifications of what is already thought, and yields a priori cognition. Reason also surreptitiously makes a priori assertions, which add something alien to the concept. | |
| From: Immanuel Kant (Critique of Pure Reason [1781], B009/A5) | |
| A reaction: This is at the heart of Kant's programme, to disentangle these two, and especially to turn a strong critical light on the second one. He does not deny the possibility of a priori knowledge beyond conceptual analysis, but is wary. |
| 21476 | A priori propositions are those we could never be seriously motivated to challenge [Schopenhauer] |
| Full Idea: A dictate of reason is the name we give to certain propositions which we hold to be true without investigation, and of which we think ourselves so firmly convinced we should be incapable of seriously testing them even if we wanted to. | |
| From: Arthur Schopenhauer (Parerga and Paralipomena [1851], I:12) | |
| A reaction: This is closer to the cautious way modern thinkers are inclined to express the idea. Even Quine would be reasonably happy with this. |
| 9158 | For Frege a priori knowledge derives from general principles, so numbers can't be primitive [Frege] |
| Full Idea: If one took the numbers as primitive, one would not be deriving their existence and character from general principles- thus controverting Frege's view of the nature of an a priori subject. | |
| From: Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884]), quoted by Tyler Burge - Frege on Apriority II | |
| A reaction: He seems to be in tune with Leibniz on this. His view begs the obvious question of where the general principles come from. I would have thought that relationships between concepts might be known a priori, without principles being involved. |
| 8259 | Kripke has breathed new life into the a priori/a posteriori distinction [Kripke, by Lowe] |
| Full Idea: The a priori/a posteriori is still taken seriously, and has had new life breathed into it by the work of Saul Kripke. | |
| From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by E.J. Lowe - The Possibility of Metaphysics 1.1 | |
| A reaction: The distinction may be a good one, despite a blurred borderline. Did Egyptian quantity surveyors begin to suspect that Pythagoras's Theorem was a necessary truth, though they couldn't prove it? A priori understanding creeps into experience. |
| 16989 | Rather than 'a priori truth', it is best to stick to whether some person knows it on a priori evidence [Kripke] |
| Full Idea: A priori is supposed to mean something which can be known independently of experience, …but possible for whom? God, or the Martians? …Instead of 'a priori truth' it is best to stick to whether some person knows it based on a priori evidence. | |
| From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1) | |
| A reaction: [compressed] This is Kripke's famous attempt to establish that 'a priori' is strictly an epistemological term, and should not be taken as a term of metaphysics (or modal semantics?). I definitely prefer the Kripke view, though it downgrades the a priori. |
| 4947 | A priori truths can be known independently of experience - but they don't have to be [Kripke] |
| Full Idea: The traditional characterisation (since Kant) goes: a priori truths are those which can be known independently of any experience - ..but that doesn't mean they MUST be known a priori. | |
| From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1) | |
| A reaction: You may discover through experience that nine matches can't be divided into two equal piles, but Leibniz (and others) say you will only see the necessity of this a priori. No necessity is visible in the matches. |
| 6982 | Long arithmetic calculations show the a priori can be fallible [Jackson] |
| Full Idea: We know that being fallible and being a priori can co-exist - the results of long numerical additions are well-known examples. | |
| From: Frank Jackson (From Metaphysics to Ethics [1998], Ch.2) | |
| A reaction: I see this realisation as a good example of progress in philosophy. Russell, who says self-evidence comes in degrees, deserves major credit. It is the key idea that once again makes rationalism respectable. |
| 16892 | Is apriority predicated mainly of truths and proofs, or of human cognition? [Burge] |
| Full Idea: Whereas Leibniz and Frege predicate apriority primarily of truths (or more fundamentally, proofs of truths), Kant predicates apriority primarily of cognition and the employment of representations. | |
| From: Tyler Burge (Frege on Apriority (with ps) [2000], 1) |
| 12390 | A priori knowledge comes from available a priori warrants that produce truth [Kitcher] |
| Full Idea: X knows a priori that p iff the belief was produced with an a priori warrant, which is a process which is available to X, and this process is a warrant, and it makes p true. | |
| From: Philip Kitcher (The Nature of Mathematical Knowledge [1984], 01.4) | |
| A reaction: [compression of a formal spelling-out] This is a modified version of Goldman's reliabilism, for a priori knowledge. It sounds a bit circular and uninformative, but it's a start. |
| 9333 | A priori belief is not necessarily a priori justification, or a priori knowledge [Horwich] |
| Full Idea: It is one thing to believe something a priori and another for this belief to be epistemically justified. The latter is required for a priori knowledge. | |
| From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §8) | |
| A reaction: Personally I would agree with this, because I don't think anything should count as knowledge if it doesn't have supporting reasons, but fans of a priori knowledge presumably think that certain basic facts are just known. They are a priori justified. |
| 20471 | Epistemic a priori conditions concern either the source, defeasibility or strength [Casullo] |
| Full Idea: There are three suggested epistemic conditions on a priori knowledge: the first regards the source of justification, the second regards the defeasibility of justification, and the third appeals to the strength of justification. | |
| From: Albert Casullo (A Priori Knowledge [2002], 2) | |
| A reaction: [compressed] He says these are all inspired by Kant. The non-epistemic suggested condition involve necessity or analyticity. The source would have to be entirely mental; the defeasibly could not be experiential; the strength would be certainty. |
| 20477 | The main claim of defenders of the a priori is that some justifications are non-experiential [Casullo] |
| Full Idea: The leading claim of proponents of the a priori is that sources of justification are of two significantly different types: experiential and nonexperiential. Initially this difference is marked at the phenomenological level. | |
| From: Albert Casullo (A Priori Knowledge [2002], 5) | |
| A reaction: He cites Plantinga and Bealer for the phenomenological starting point (that some knowledge just seems rationally obvious, certain, and perhaps necessary). |
| 3306 | The clearest a priori knowledge is proving non-existence through contradiction [Benardete,JA] |
| Full Idea: One proves non-existence (e.g. of round squares) by using logic to derive a contradiction from the concept; it is precisely here, in such proofs, that we find the clearest example of a priori knowledge. | |
| From: José A. Benardete (Metaphysics: the logical approach [1989], Ch. 4) |
| 20298 | The traditional a priori is justified without experience; post-Quine it became unrevisable by experience [Rey] |
| Full Idea: Where Kant and others had traditionally assumed that the a priori concerned beliefs 'justifiable independently of experience', Quine and others of the time came to regard it as beliefs 'unrevisable in the light of experience'. | |
| From: Georges Rey (The Analytic/Synthetic Distinction [2013], 3.7) | |
| A reaction: That throws a rather striking light on Quine's project. Of course, if the a priori is also necessary, then it has to be unrevisable. But is a bachelor necessarily an unmarried man? It is not necessary that 'bachelor' has a fixed meaning. |
| 9128 | It is propositional attitudes which can be a priori, not the propositions themselves [Sorensen] |
| Full Idea: The primary bearer of apriority is the propositional attitude (believing, knowing, guessing and so on) rather than the proposition itself. A proposition could be a priori to homo sapiens but a posteriori to Neandethals. | |
| From: Roy Sorensen (Vagueness and Contradiction [2001], 6.3) | |
| A reaction: A putative supreme being is quite useful here, who might even see the necessity of Arsenal beating Manchester United next Saturday. Unlike infants, adults know a priori that square pegs won't fit round holes. |
| 9130 | Attributing apriority to a proposition is attributing a cognitive ability to someone [Sorensen] |
| Full Idea: Every attribution of apriority to a proposition is tacitly an attribution of a cognitive ability to some thinker. | |
| From: Roy Sorensen (Vagueness and Contradiction [2001], 6.3) | |
| A reaction: The ability would include a range of background knowledge, as well as a sheer power of intellect. If you know all of Euclid's theorems, you will spot facts about geometrical figues quicker than me. His point is important. |
| 4645 | 'A priori' does not concern how you learn a proposition, but how you show whether it is true or false [Baggini /Fosl] |
| Full Idea: What makes something a priori is not the means by which it came to be known, but the means by which it can be shown to be true or false. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §4.01) | |
| A reaction: Helpful. Kripke in particular has labelled the notion as an epistemological one, but that does imply a method of acquiring it. Clearly I can learn an a priori truth by reading it the newspaper. |