- Project MUSE - Kant's Theory of A Priori Knowledge (review)
- A priori and a posteriori
- New Essays on the A Priori
- Most Downloaded Articles
By contrast, if a proposition is known or is capable of being known a posteriori , then it is known as a result of experiential evidence. For example, your knowledge that there is a computer in front of you, that you ate breakfast this morning, that snow is white, that Indian elephants have smaller ears than African elephants, all count as a posteriori knowledge. The distinction between a priori and a posteriori corresponds to the distinction between empirical and non-empirical knowledge.
It is important to distinguish  the claim that a proposition is knowable without any experience from  that claim that experience is not necessary for the proposition to be known. Clearly this knowledge requires the conceptual and linguistic capacities involved in an understanding of English. Crucially, then, to say that a proposition is known a priori is not to endorse , but only to endorse .
A proposition is known a priori only if, in addition to any experience needed to have beliefs at all, or to grasp the proposition that p , your justification for believing that p does not depend on experience.
Project MUSE - Kant's Theory of A Priori Knowledge (review)
Similarly, your knowledge that women are female human beings presupposes, but is not based on, experience, and counts as a priori knowledge. Although the primary usage of the terms a priori and a posteriori is with reference to knowledge and justification, philosophers sometimes also speak of a priori or a posteriori concepts. It is reasonable to think that concepts are constituents of propositions, and are therefore neither true nor false, and so are not capable of being known.
Reference to a priori concepts may then be naturally understood as those that have significance or meaning independently of experience and do not require experience for legitimatization. Similarly, a posteriori concepts are those that cannot be understood independently of particular experiences.
The distinction between a priori and a posteriori knowledge must be separated from two other distinctions with which it is closely connected and sometimes confused. These are the metaphysical distinction between necessary and contingent truths and the semantic distinction between analytic and synthetic propositions. Historically, most philosophers have maintained that all a priori knowledge corresponds to knowledge of necessary truths.
A priori and a posteriori
A necessary truth is a proposition that cannot be false; it is true in all possible worlds. By contrast, a contingent truth is a proposition that is true, as things are, but is conceivably false. For example, it seems contingently true that the population of New York is greater than five million.
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This proposition is said to be contingent because we can easily imagine it to be false. Whatever the initial plausibility of the claim that a priori knowledge is restricted to knowledge of necessary truths, this view has been challenged by some eminent contemporary philosophers. Saul Kripke argues that some propositions known a priori are contingently true, while some propositions known a posteriori are necessarily true.
Kripke argues that although this proposition is known a priori it is contingently true since the length of S might not have been one meter long. A number of philosophers have held that a priori knowledge is restricted to knowledge of analytic propositions, and a posteriori knowledge to synthetic propositions see the entry on the analytic-synthetic distinction.
An analytic proposition is roughly, a proposition true by meaning alone, whereas, generally, the truth or falsity of a synthetic proposition does not depend on meaning. Kant famously challenged the alignment of a priori with analytic and a posteriori with synthetic, arguing that truths of arithmetic and geometry are synthetic propositions, which are capable of being known a priori.
However, the analytic explanation of a priori knowledge has undergone several criticisms. Most notably, the American philosopher W. Quine argued that the analytic-synthetic distinction is illegitimate see Quine's rejection of the analytic-synthetic distinction. Quine states: "But for all its a priori reasonableness, a boundary between analytic and synthetic statements simply has not been drawn.
That there is such a distinction to be drawn at all is an unempirical dogma of empiricists, a metaphysical article of faith. The metaphysical distinction between necessary and contingent truths has also been related to a priori and a posteriori knowledge. A proposition that is necessarily true is one whose negation is self-contradictory thus, it is said to be true in every possible world. Consider the proposition that all bachelors are unmarried. Theoretically, its negation, the proposition that some bachelors are married, is incoherent, because the concept of being unmarried or the meaning of the word "unmarried" is part of the concept of being a bachelor or part of the definition of the word "bachelor".
To the extent that contradictions are impossible, self-contradictory propositions are necessarily false, because it is impossible for them to be true. Thus, the negation of a self-contradictory proposition is supposed to be necessarily true. By contrast, a proposition that is contingently true is one whose negation is not self-contradictory thus, it is said that it is not true in every possible world. As Jason Baehr states, it seems plausible that all necessary propositions are known a priori , because "[s]ense experience can tell us only about the actual world and hence about what is the case; it can say nothing about what must or must not be the case.
Following Kant, some philosophers have considered the relationship between aprioricity, analyticity, and necessity to be extremely close. According to Jerry Fodor, " Positivism , in particular, took it for granted that a priori truths must be necessary Analytic propositions were largely taken to be "true by virtue of meanings and independently of fact",  while synthetic propositions were not—one must conduct some sort of empirical investigation, looking to the world, to determine the truth-value of synthetic propositions.
Aprioricity, analyticity, and necessity have since been more clearly separated from each other. The American philosopher Saul Kripke , for example, provided strong arguments against this position. Kripke argued that there are necessary a posteriori truths, such as the proposition that water is H 2 O if it is true. According to Kripke, this statement is necessarily true since water and H 2 O are the same thing, they are identical in every possible world, and truths of identity are logically necessary and a posteriori since it is known only through empirical investigation.
Following such considerations of Kripke and others such as Hilary Putnam , philosophers tend to distinguish more clearly the notion of aprioricity from that of necessity and analyticity. Kripke's definitions of these terms, however, diverge in subtle ways from those of Kant. Taking these differences into account, Kripke's controversial analysis of naming as contingent and a priori would best fit into Kant's epistemological framework by calling it "analytic a posteriori". Thus, the relationship between aprioricity, necessity, and analyticity is not easy to discern.
Sign In Don't have an account? Please help to improve this page yourself if you can.. Contents [ show ]. In this pair of articles, Palmquist demonstrates that the context often determines how a particular proposition should be classified. A proposition that is synthetic a posteriori in one context might be analytic a priori in another. Baehr, Jason. Boghossian, Paul.
New Essays on the A Priori
Boghossian, P. In Cottingham, et al. Fodor, Jerry. Greenberg, Robert.
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Hume, David. Jenkins, C. Kant, Immanuel. Critique of Pure Reason , trans. Smith London: Macmillan, Online text Kant, Immanuel.