Willard Van Orman Quine in the context of "Logician"

Philosophy of language is the philosophical study of the nature of language. It investigates the relationship between language, language users, and the world. Investigations may include inquiry into the nature of meaning, intentionality, reference, the constitution of sentences, concepts, learning, and thought.

Gottlob Frege and Bertrand Russell were pivotal figures in analytic philosophy's "linguistic turn". These writers were followed by Ludwig Wittgenstein (Tractatus Logico-Philosophicus), the Vienna Circle, logical positivists, and Willard Van Orman Quine.

Analytic philosophy is a broad movement and methodology within contemporary Western philosophy, especially anglophone philosophy, focused on: analysis as a philosophical method; clarity of prose; rigor in arguments; and making use of formal logic, mathematics, and to a lesser degree the natural sciences. It is further characterized by the linguistic turn, or a concern with language and meaning. Analytic philosophy has developed several new branches of philosophy and logic, notably philosophy of language, philosophy of mathematics, philosophy of science, modern predicate logic and mathematical logic.

The proliferation of analysis in philosophy began around the turn of the 20th century and has been dominant since the latter half of the 20th century. Central figures in its historical development are Gottlob Frege, Bertrand Russell, G. E. Moore, and Ludwig Wittgenstein. Other important figures in its history include Franz Brentano, the logical positivists (especially Rudolf Carnap), the ordinary language philosophers, W. V. O. Quine, and Karl Popper. After the decline of logical positivism, Saul Kripke, David Lewis, and others led a revival in metaphysics.

The analytic–synthetic distinction is a semantic distinction used primarily in philosophy to distinguish between propositions (in particular, statements that are affirmative subject–predicate judgments) that are of two types: analytic propositions and synthetic propositions. Analytic propositions are true or not true solely by virtue of their meaning, whereas synthetic propositions' truth, if any, derives from how their meaning relates to the world.

While the distinction was first proposed by Immanuel Kant, it was revised considerably over time, and different philosophers have used the terms in very different ways. Furthermore, some philosophers (starting with Willard Van Orman Quine) have questioned whether there is even a clear distinction to be made between propositions which are analytically true and propositions which are synthetically true. Debates regarding the nature and usefulness of the distinction continue to this day in contemporary philosophy of language.

In philosophy of science, the Duhem–Quine thesis, also called the Duhem–Quine problem, says that unambiguous falsifications of a scientific hypothesis are impossible, because an empirical test of the hypothesis requires one or more background assumptions. Rather than disproving the main hypothesis, the blame can be placed on one of the background beliefs or "auxiliary" hypotheses. It is named after French theoretical physicist Pierre Duhem and American logician Willard Van Orman Quine, who wrote about similar concepts.

In recent decades, the set of associated assumptions supporting a thesis sometimes is called a bundle of hypotheses, i.e. a hypothesis and its background assumptions. Although a bundle of hypotheses as a whole can be tested against the empirical world and be falsified if it fails the test, the Duhem–Quine thesis says it is impossible to isolate a single hypothesis in the bundle, a viewpoint called confirmation holism.

Naturalized epistemology is a collection of philosophic views about the theory of knowledge that emphasize the role of natural scientific methods. This shared emphasis on scientific methods of studying knowledge shifts the focus of epistemology away from many traditional philosophical questions, and towards the empirical processes of knowledge acquisition. There are noteworthy distinctions within naturalized epistemology. Replacement naturalism maintains that we should abandon traditional epistemology and replace it with the methodologies of the natural sciences. The general thesis of cooperative naturalism is that traditional epistemology can benefit in its inquiry by using the knowledge we have gained from cognitive sciences. Substantive naturalism focuses on an asserted equality of facts of knowledge and natural facts.

The name for such epistemology was coined by W. V. O. Quine. Objections to naturalized epistemology have targeted features of the general project as well as characteristics of specific versions. Some objectors argue that natural scientific knowledge cannot be circularly grounded by the knowledge obtained through cognitive science, which is itself a natural science. This objection from circularity has been aimed specifically at strict replacement naturalism. There are similar challenges to substance naturalism that maintain that the substance naturalists' thesis that all facts of knowledge are natural facts is not only circular but fails to accommodate certain facts. Several other objectors have found fault in the inability of naturalized methods to adequately address questions about what value forms of potential knowledge have or lack.

Neurath's boat (or Neurath's ship) is a simile used in anti-foundational accounts of knowledge, especially in the philosophy of science. It was first formulated by Otto Neurath. It is based in part on the Ship of Theseus which, however, is standardly used to illustrate other philosophical questions, to do with problems of identity. It was popularised by Willard Van Orman Quine in Word and Object (1960).

Neurath used the simile in several occasions, first in "Problems in War Economics" (1913). In "Anti-Spengler" (1921), he wrote:

The Society of Fellows is a group of scholars selected at the beginnings of their careers by Harvard University for their potential to advance academic wisdom, upon whom are bestowed distinctive opportunities to foster their individual and intellectual growth. Junior fellows are appointed by senior fellows based upon previous academic accomplishments and receive generous financial support for three years while they conduct independent research at Harvard University in any discipline, without being required to meet formal degree requirements or to be graded in any way. The only stipulation is that they maintain primary residence in Cambridge, Massachusetts, for the duration of their fellowship. Membership in the society is for life.

The society has contributed numerous scholars to the Harvard faculty and thus significantly influenced the tenor of discourse at the university. Among its best-known members are philosopher W. V. O. Quine, Jf '36; behaviorist B. F. Skinner, Jf '36; double Nobel laureate John Bardeen, Jf '38; economist Paul Samuelson, Jf '40; historian Arthur M. Schlesinger, Jr., Jf '43; presidential advisor McGeorge Bundy, Jf '48; historian and philosopher of science Thomas Kuhn, Jf '51; linguist and activist Noam Chomsky, Jf '55; biologist E. O. Wilson, Jf '56; cognitive scientist Marvin Minsky, Jf '57; former dean of the Harvard faculty, economist Henry Rosovsky, Jf '57; economist and whistleblower Daniel Ellsberg, Jf '59; philosopher Saul Kripke, Jf '66; ethnographer and photographer Bruce Jackson, Jf '67; Fields Medal-winning theoretical physicist Ed Witten, Jf '81; and writer, critic, and editor Leon Wieseltier, Jf '82.

In philosophy of science, confirmation holism, also called epistemological holism, is the view that no individual statement can be confirmed or disconfirmed by an empirical test, but rather that only a set of statements (a whole theory) can be so. It is attributed to Willard Van Orman Quine who motivated his holism through extending Pierre Duhem's problem of underdetermination in physical theory to all knowledge claims.

Duhem's idea was, roughly, that no theory of any type can be tested in isolation but only when embedded in a background of other hypotheses, e.g. hypotheses about initial conditions. Quine thought that this background involved not only such hypotheses but also our whole web of belief, which, among other things, includes our mathematical and logical theories and our scientific theories. This last claim is sometimes known as the Duhem–Quine thesis.