Logical Empiricism
The logical empiricism (sometimes called logical positivism, neo-positivism, empiricism or rational) is a school philosophy mainly illustrated by the Vienna Circle , a group founded by bringing together scientists and philosophers in Vienna in the years 1920. Although logical positivism is known for his radical proposals, the Vienna Circle was primarily a place for discussion among scientists, ( Niels Bohr and Einstein are occasionally intervened) and philosophers who do not share the same beliefs. It forms around the philosopher Moritz Schlick , and there are particular mathematicians Hans Hahn , Kurt Gdel and Karl Menger , the physicist Philipp Frank , the sociologist Otto Neurath , philosophers Rudolf Carnap and Victor Kraft , and students in philosophy as Friedrich Waismann and Herbert Feigl. At the same time, in Berlin , supporters gather around Hans Reichenbach and the Gesellschaft fr Empirische Philosophie (Society for empirical philosophy). Founded in 1928, it welcomed Carl Gustav Hempel , Richard von Mises , David Hilbert and Kurt Grelling.
The Vienna Circle is the author of a manifesto published in 1929 under the title The scientific world , where he exhibited his main theses. It also included Alfred J. Ayer , who summarized the major theses of logical positivism, in his work Language, Truth and Logic (1936). We can briefly summarize them as follows: there is not, as alleged by Kant , of synthetic judgments a priori. Therefore, the metaphysics can not be a science. In addition, any statement of knowledge is either analytic or synthetic a posteriori, and thus verifiable by experience. Therefore, forward ethical and metaphysical are as set out prescriptive and not descriptive and verifiable necessarily "meaningless" The legacy of positivist Logical positivism, or neo-positivism comes from the positivism of Ernst Mach , of Henri Poincare and the thought of the young Wittgenstein. Positivism is primarily focused on the study of science. It seeks to break with the methods of theology and the " metaphysical ", which would seek, in their view, the gods or causes to explain the mysterious phenomena. Positivism waives give causes to phenomena and seeks only to give laws to describe and predict them. On this point, logical positivism is perfectly faithful to the first positivism , formulated in the nineteenth century by Auguste Comte (one might even add that it does not differ on this point, the critical Kantian distinction between knowledge and the phenomena, impossible, noumena : logical positivism and shared, to some extent, the perspective on the Kantian distinction between science and belief ). This is to describe and justify the scientific discoveries by analyzing their approach and their principles, to ask how the world can it be? (And why is it not so?). It is however different from the positivism of Auguste Comte by his empiricism. Comte, in fact, the experience sensitive is largely determined by the theories we have to understand and has no priority. While logical positivism considers the continuation of the empiricism of Locke and Hume , that sensation is the foundation of knowledge. The sensations are absolutely unmistakable, and can, once formulated in precise language, used to create scientific theories. The feelings must take the form of protocol sentences describing a certain sensation was felt at such place and such time by such person. The proposed protocol is absolutely true, science has only to understand the relationships between these proposals for a comprehensive theory of physical reality. In that, Ernst Mach is the forerunner of the Vienna Circle . According to the manifesto of 1929 , science is a worldview in itself, and not just a discipline to which we may or may not engage. The policy also must renounce his "metaphysical dogma" and be led by scientific principles The dimension "logic" of positivism The main novelty of the Vienna Circle is its use of logic developed by Frege and Russell for the study of scientific problems. The design philosophy is so radically changed, to focus on epistemology and philosophy of science : the rest is merely false problems for which we can not expect any scientific solution. Philosophy must be the "logic of science", that is to say, consider scientific theories, and identify the logical relationships. It should show how the language of observation made by the "protocol proposals," or "observational statements", provides the premises on which we can deduce the main scientific, or theoretical, per se. Science, meanwhile, is threatened by the metaphysical , simple myth akin to poetry. Carnap says that the metaphysician is a musician with no musical talent " ). According to positivism, statements are divided into analytic statements (proposals of logic and mathematics, reducible to tautologies ) and synthetic statements , which constitute the empirical sciences. The analytic statements do not learn about the world, and are true to the meaning of terms they contain (for example, "all bachelors are unmarried"). These are proposals and not Sinnlos unsinnig: not "absurd" but "meaningless" . The reductionist logic of Frege and Russell then show, by reducing the mathematical logic of mathematical statements, as they are formed of tautologies . Agreeing with Wittgenstein , Russell abandoned his position of 1903 (in Principles of Mathematics), where he considered that Kant was right in the Critique of Pure Reason , to characterize the mathematics of "synthetic", but that should have also given this status to logical statements . For a synthetic statement is meaningful, it must, therefore, focuses on an empirical fact observed. If it is not verifiable using the experience, then it is pseudo-science or metaphysics. Thus a proposal stating "there is a God" is neither true nor false but simply meaningless because unverifiable. Empiricism and logic divides the set of scientific theories as "logical expressions" and "descriptive phrases" bring together those logical connectives and quantifiers , and are shared by all the sciences, while they are specific to each science (eg the concept of " strength "of" electron "or" molecule ") . Descriptive terms themselves are divided into "observational language" and "theoretical language": language observational means publicly observable entities (that is to say, observable seen naked, for example a "chair"), while theoretical language that includes terms denoting unobservable entities (or more difficult to observe, as a " proton ") . From this distinction between descriptive statements observational and descriptive statements theoretical verificationist theory of meaning comes to postulate that "a statement has a cognitive meaning (ie, makes a statement true or false) if and only if it is not analytic or contradictory and it is a logical deduction of a class of finite observable statements. " According to the distinction among the descriptive statements, statements between observational and theoretical statements, positivists try to "translate the theoretical vocabulary in the observational vocabulary" , since only it can provide empirical support for knowledge. In The Logic of Modern Physics (1927), PW Bridgman , future Nobel Prize in Physics and a supporter of the operationalism , said it was possible to achieve such a complete translation . Similarly, Ernst Mach , before him, and Rudolf Carnap , Der Aufbau der Welt Logical (1928), believed that such a reduction was possible in observational vocabulary . But in 1936-1937, Carnap shows the failure of this program, in an article entitled "Testability and Meaning . Consider the statement "A body is soluble if and only if when it was immersed in water it dissolves, which can translate into the observational theoretical concept of" solubility " . The antecedent (body is soluble) is true even when the antecedent of the second proposition is false: in other words, every body is so soluble that it has not dipped in water . Carnap then proposes to use statements of "reduction", eg "If a body is placed in water (at t), then this body is soluble if and only if it is dissolved (other time t). "Carnap therefore reverse the logical connectives : the biconditionnel ( iff ) takes the place of conditional . But this statement of reduction is lower than the definition in terms of observational: it specifies only partially the meaning of "soluble" . Positivists will then distinguish among mature scientific theories, and axiomatizable between the theoretical vocabulary, consisting of axioms or postulate and theorems derived from them, and observational predictions, made using vocabulary terms observational, these being attached to it by a system of "matching rules" ( Carnap and Nagel , Reichenbach speaks of "coordinating definitions" FP Ramsey and Campbell a "dictionary", and Hempel "system of interpretation" ). Alfred Ayer and criticized for this reason, the idealism of the British philosopher FH Bradley , in his book Language, Truth and Logic (1936), which popularized the theories of logical positivism in the Anglo-Saxon. The criterion verificationist was also intended to be used in the sciences, chased the metaphysical statements that were still present. Ayer also defended a conception metaethics described as a sentimentalist in this book, which opposes any moral cognitivism : the moral values can not be the subject of logical propositions, it is not possible, he says, to to argue rationally in moral matters. In addition, the Vienna Circle sharing an instrumental conception of scientific theories : they must allow to make prediction observable, not to explain the reality , that is to say to give representations (true or false) of reality . For cons, the status of logic is not unanimity in the Vienna Circle, and was subject to change views. Schlick defends a conception close to Wittgenstein , that makes sense an activity and not a theory , it recognizes in Introduction to Semantics (1942), written after the work of Tarski , "the need to resort to concepts semantics (such as reference and truth ) to determine the cognitive status of a language statements " . In 1934, parsing, logic, Carnap, allows him to restate the "formal idiom" the sentences of the "material idiom," which allows him to show he believes that some statements are metaphysical not absurd, but "give the illusion of transmitting information to the world" . He then joined the thesis of Wittgenstein in the Tractatus Logico-Philosophicus , which radically distinguishes the science of philosophy: philosophical statements, as they are not absurd, does not relate to the world, but about language: they express a preference for a linguistic framework . In the Logic of Scientific Discovery , Karl Popper has criticized the use of criterion verificationist as a scientific criterion of demarcation , distinguishing what is science and what is not. For him, a theory (not a statement) is scientific only if it is refutable. Quine , in Two Dogmas of Empiricism , it takes a more radical theories of the logical empiricism. He attacks the idea that we can make a sharp distinction between synthetic statements, relating to "facts", and analytic statements , so true a priori and necessary , only under the rules of logic. For him, the notion of analytical statement is unclear. The second dogma of empiricism "according to Quine, the reductionism of any statement to statements about sensations (the" protocol sentences "or" observational ") is not tenable. Quine advocates a holistic approach : the experience can not disprove a particular statement, but involves the whole theory , the investigator has the choice to change statements they want (they are "observational" or "theoretical") to give his theory to the experiment. Therefore, it suggests that the logic may also to some extent, and ultimately be revised, as any statement of fact. Unlike Carnap, who believed in the existence of real analytic set a priori , Quine thinks that no true statement, albeit it a priori, is compelling . It highlights that even Euclidean geometry was replaced by a non-Euclidean geometry , and that nothing prevents a priori evidence that the logic is classical could be replaced by a different logic . Another critic, on the dichotomy established by Carnap between "observational statements" and "theoretical statements," as well as the hope of Carnap to build a formal language , precise, without going through imprecise terms, "pre- scientists, "was developed by Hilary Putnam , in an article entitled "What theories are not" . This is based on two main points: The theory of meaning verificationist
Translating the theoretical vocabulary in the observational vocabulary
The sentimentalism of Alfred Ayer
The instrumental conception of scientific theories
The status of logic
Criticism of logical empiricism
References
See also
Bibliography
Founding Texts
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