Epistemology

====Analytic–synthetic distinction====
[[File:Immanuel Kant portrait c1790.jpg|thumb|The analytic–synthetic distinction was first proposed by [[Immanuel Kant]].]]
{{Main|Analytic–synthetic distinction}}
[[Immanuel Kant]], in his ''[[Critique of Pure Reason]]'', drew a distinction between "analytic" and "synthetic" propositions. He contended that some propositions are such that we can know they are true just by understanding their meaning. For example, consider, "My father's brother is my uncle." We can know it is true solely by virtue of our understanding in what its terms mean. Philosophers call such propositions "analytic". Synthetic propositions, on the other hand, have distinct subjects and predicates. An example would be, "My father's brother has black hair." Kant stated that all mathematical and scientific statements are synthetic a priori propositions because they are [[logical truth|necessarily true]], but our knowledge about the attributes of the mathematical or physical subjects we can only get by logical inference.

While this distinction is first and foremost about [[Meaning (philosophy of language)|meaning]] and is therefore most relevant to the [[philosophy of language]], the distinction has significant epistemological consequences, seen most prominently in the works of the [[logical positivism|logical positivists]].<ref name="SEP Analytic Synthetic"/> In particular, if the set of propositions which can only be known ''a posteriori'' is coextensive with the set of propositions which are synthetically true, and if the set of propositions which can be known ''a priori'' is coextensive with the set of propositions which are analytically true (or in other words, which are true by definition), then there can only be two kinds of successful inquiry: Logico-mathematical inquiry, which investigates what is true by definition, and empirical inquiry, which investigates what is true in the world. Most notably, this would exclude the possibility that branches of philosophy like [[metaphysics]] could ever provide informative accounts of what actually exists.<ref name="SEP apriori"/><ref name="SEP Analytic Synthetic"/>

The American philosopher [[Willard Van Orman Quine|W. V. O. Quine]], in his paper "[[Two Dogmas of Empiricism]]", famously challenged the analytic-synthetic distinction, arguing that the boundary between the two is too blurry to provide a clear division between propositions that are true by definition and propositions that are not. While some contemporary philosophers take themselves to have offered more sustainable accounts of the distinction that are not vulnerable to Quine's objections, there is no consensus about whether or not these succeed.<ref>Russell, G.: Truth in Virtue of Meaning: A Defence of the Analytic/Synthetic Distinction. Oxford: Oxford University Press. 2008</ref>