LOGICAL EMPIRICISM

INTRODUCTION.
There is a very popular and influential school of contemporary analytic philosophers known as logical empiricists. The goal of the school, also known as "logical positivisism," was to purify philosophy - shifting out its metaphysical elements, and reconstituting the discipline with logic as its organon or instrument. The goal of philosophy in this sense is working out the implications of the logic of science.
HISTORY OF LOGICAL EMPIRICISM.
Their philosphical ancestry is both British and Continental. On the British side, the line of descent may be traced back to Bertrand Russell (twentieth century) and John Stuart Mill (nineteenth century) to the Scotish philosopher David Hume (eighteenth century). The more important heritage of logical empiricism is from the Continental side and stems from the doctrines of a group of twentieth century philosophers known in the years before World War II as "the Vienna Circle." The group included Ludwig Wittgenstein, Morris Schlick, and Rudolf Carnap. The leaders of the Vienna Circle and their disciples were known as logical positivists - "logical" because their constructive work was concerned with the analysis of logic and language; "positive" because of the kinship of their enterprise to that of nineteenth-century French philosopher Auguste Comte, an admirer of the sciences, who believed that significant knowledge concerns only that which is open to "positive" observation. Cross-fertilization took place between these kindred British and Continental philosophic strains. The contemprary English logical empiricist A. J. Ayer acknowledges his debt to both Russell and Wittgenstein, who themselves influenced each other. Ayer's famous little book Language, Truth, and Logic (1936) popularized the tenets of the logical positivists. According to C. E. M. Joad, Ayer's book "has in Oxford since the end of the war acquired almost the status of a philosophic Bible." [1]
The general tone of the early logical positivists was harsh and dogmatic. The maintained that nearly all of traditional philosophy, and a great deal else besides, was non-sense, and that future philosophers would confine themselves to logical analysis. Some of the extremes to which the earlier logical positivists pushed their doctrines seem today rather amusing to the critics of the movement. For example, Wittgenstein's Tractatus Logico-Philosophicus demonstrates that a staggering quantity of what normally passes for meaningful statements is in fact nonsense. Then, at the conclusion of the Tractatus, Wittengenstein makes the startling announcement that his own work is nonsense too. But, he reassures his readers, it is useful nonsense; it is like a ladder one climbs over, then pushes away because it is no longer needed. [2] Logical empiricism is the name that is given to the doctrines of a school of analyic philosophy, popular today in England and America, which has developed the methods of logical positivism within a broader framework.
A variety of the logical emiricists approach, with particular reference to the methods of physical sciences, is known as operationalism, a term introduced by P. W. Bridgman (1882-1963). According to Bridgman, the meaning of a scientific concept is set forth in terms of the operations we use to define it. For example, the meaning of the word "foot" as a unit of length, is equivalent to the measuring operation we perform when we want to find out whether something is a foot long. Sentences which assert sccientific hypothese are meaningful only if the nature of those operations which could test them can be specified. [3]
HISTORY OF POSITIVISM.
Positivism is that family of philosophies characterized by an extremely positive evaluation of science and the scientific method. In its earlier versions, the methods of science were held to have the potential not only of reforming philosophy but society as well. Later versions have concentrated on the reform of philosophy.
The term "positivism" was introduced by Claude-Henri Saint-Simon (1760-1825) for whom the implications of the positive philosophy extended beyond philosophy to political, educational, and religious reform. He found society alternating between critical and organic epochs.
Auguste Comte (1798-1857), who popularized and systematized the use of the term "positivism" and "positive philosophy," was for seven years Saint-Simon's student and collaborator. Comte argued that societies proceed from a theological stage through a metaphysical stage into a scientific stage where the positive philosophy is dominant.
The term "positive philosophy" was also used by Friedrich Wilhelm Schelling (1775-1854) who employed it to distinguish the final stage of his philosophy from its earlier stages, which seemed to him largely negative and critical. Since this final stage recognized a philosophical validity in religious experience and mythology. Schelling's use of the term is very different from that of Saint-Simon and Comte, almost the polar opposite in fact. And even though Schelling's usage may have come first both in lecture and manuscript, the material of this stage of his thought was published posthummously. Saint-Simon's usage has primacy in terms both of publication and acceptance.
The most powerful development of positivist analysis, however, came from the Vienna Circle of Logical Positivists. The influence of this group, among whose many representatives are Schilck and Carnap, has been so great that today Positivism usually means Logical Positivism.
Alfred J. Ayer (1910-), who worried the verifiability criterion of meaning - favored by positivists - through a number revisions, has been the most persistent English expositor of Logical Positivism or, as he prefers to call his position, logical empiricism. In the tradition of David Hume (1711-1776), Ayer holds that all genuine statements are either empirical or analytic. The truths of logic and mathematics are analytic and devoid of factual content. At the same time, Ayer holds, they are not arbitary. He specifically says that the rules of logic are necessary. Ayer has considered at great length the criterion which should apply to all genuine empirical factual propositions. Ayer holds that the appropriate criterion has to do with the verifiability of the statement or proposition. But the appropriate expression of this principle has been extremely difficullt to obtain. According to Ayer, the criterion of verifiability, as advanced by logical positivists, held that a sentence is significant if one knows how to verify the proposition which the sentence expresses. Ayer holds that it is enough that the proposition be "verifiable in principle." According to Ayer, logical positivists required that the proposition in question be conclusively established in experience; that is, that the strong sense of "verifiable" be used. Ayer holds it is sufficient that the proposition be "rendered probable by experience"; that is, that the weak sense of "verifiable" be used. Finally, Ayer holds, it is not essential that a genuine factual proposition be equivalent to an experimental proposition. It is enough that some factual propositions can be deduced from it in conjunction with certain other premises without being deducible from these premises alone. On the basis of these modifications of the doctrine of logical positivism, Ayer calls himself a logical empiricist.
The verifiability criterion was subject to further qualification in the second edition of Language, Truth, and Logic. In this revision, the criterion is more complex that in its original form. But any empirical, or non-analytic, statement which does not meet the demands of the verifiability criterion is to be regarded as meaningless. Ayer believed that statements of metaphysics, theology, ethics, and aesthetics are alike in failing to pass the test. In the latter two fields, the statements are regared by Ayer as emotive with a note of command implicit in them. Ayer regarded the function of philosophy as analysis. And this analysis is the clarification of statements and their interpretation. The procedure involves the translation of the statements needing clarification into other statements which contain neither the key words of the original nor synomyms for them. In practice, philosophical analysis becomes for Ayer often a translation of sentences about material objects into a sense-datum language. On the basis of this, some have regarded him as a phenomenalist.
Gustav Bergmann (1905-), a lapsed positivist of the Vienna Circle, argues that all positivists are either materialists or phenomenalists. Born in Vienna, Bergmann studied at the University of Vienna as one of the second generation Logical Positivists. Bergmann traces his own course of thought from that of reluctant Phenomenalist to Phenomenological Realist to a Realism with the "phenomenological dross" removed. He held that ontology is primary, and epistemology is regarded as the ontology of the knowing situation.

END NOTES

[1] C. E. M. Joad, A Critique of Logical Positivism
(University of Chicago Press, 1950), p. 9.

[2] Ludwig Wittenstein, Tractatus Logico-Philosophicus
(Harcourt, Brace and CCo., 1922), p. 189.

[3]P. W. Bridgman, The Logic of Modern Physics
(The Macmillan Company, 1927).