Verificationism, also known as the verification principle or the verifiability criterion of meaning, is a doctrine in philosophy which asserts that a statement is meaningful only if it is either empirically verifiable (can be confirmed through the senses) or a tautology (true by virtue of its own meaning or its own logical form). Verificationism rejects statements of metaphysics, theology, ethics and aesthetics as meaningless in conveying truth value or factual content, though they may be meaningful in influencing emotions or behavior. [1]
Verificationism was a central thesis of logical positivism, a movement in analytic philosophy that emerged in the 1920s by philosophers who sought to unify philosophy and science under a common naturalistic theory of knowledge. [2] The verifiability criterion underwent various revisions throughout the 1920s to 1950s. However, by the 1960s, it was deemed to be irreparably untenable. [3] Its abandonment would eventually precipitate the collapse of the broader logical positivist movement. [4]
The roots of verificationism may be traced to at least the 19th century, in philosophical principles that aim to ground scientific theory in verifiable experience, such as C.S. Peirce's pragmatism and the work of conventionalist Pierre Duhem, [3] who fostered instrumentalism. [5] Verificationism, as principle, would be conceived in the 1920s by the logical positivists of the Vienna Circle, who sought an epistemology whereby philosophical discourse would be, in their perception, as authoritative and meaningful as empirical science. [6] The movement established grounding in the empiricism of David Hume, [7] Auguste Comte and Ernst Mach, and the positivism of the latter two, borrowing perspectives from Immanuel Kant and defining their exemplar of science in Einstein's general theory of relativity. [8]
Ludwig Wittgenstein's Tractatus , published in 1921, established the theoretical foundations for the verifiability criterion of meaning. [9] Building upon Gottlob Frege's work, the analytic–synthetic distinction was also reformulated, reducing logic and mathematics to semantical conventions. This would render logical truths (being unverifiable by the senses) tenable under verificationism, as tautologies. [10]
Logical positivists within the Vienna Circle recognized quickly that the verifiability criterion was too stringent. Specifically, universal generalizations were noted to be empirically unverifiable, rendering vital domains of science and reason, including scientific hypothesis, meaningless under verificationism, absent revisions to its criterion of meaning. [11]
Rudolf Carnap, Otto Neurath, Hans Hahn and Philipp Frank led a faction seeking to make the verifiability criterion more inclusive, beginning a movement they referred to as the "liberalization of empiricism". Moritz Schlick and Friedrich Waismann led a "conservative wing" that maintained a strict verificationism. Whereas Schlick sought to redefine universal generalizations as tautological rules, thereby to reconcile them with the existing criterion, Hahn argued that the criterion itself should be weakened to accommodate non-conclusive verification. [12] Neurath, within the liberal wing, proposed the adoption of coherentism, though challenged by Schlick's foundationalism. However, his physicalism would eventually be adopted over Mach's phenomenalism by most members of the Vienna Circle. [11] [13]
In 1936, Carnap sought a switch from verification to confirmation. [11] Carnap's confirmability criterion (confirmationism) would not require conclusive verification (thus accommodating for universal generalizations) but allow for partial testability to establish degrees of confirmation on a probabilistic basis. Carnap never succeeded in finalising his thesis despite employing abundant logical and mathematical tools for this purpose. In all of Carnap's formulations, a universal law's degree of confirmation was zero. [14]
In Language, Truth and Logic , published that year, A. J. Ayer distinguished between strong and weak verification. This system espoused conclusive verification, yet allowed for probabilistic inclusion where verifiability is inconclusive. He also distinguished theoretical from practical verifiability, proposing that statements that are verifiable in principle should be meaningful, even if unverifiable in practice. [15] [16]
Philosopher Karl Popper, a graduate of the University of Vienna, though not a member within the ranks of the Vienna Circle, was among the foremost critics of verificationism. He identified three fundamental deficiencies in verifiability as a criterion of meaning: [17]
Popper regarded scientific hypotheses to never be completely verifiable, as well as not confirmable under Carnap's thesis. [9] [18] He also considered metaphysical, ethical and aesthetic statements often rich in meaning and important in the origination of scientific theories. [9]
Other philosophers also voiced their own criticisms of verificationism:
In The Logic of Scientific Discovery (1959), Popper proposed falsifiability, or falsificationism. Though formulated in the context of what he perceived were intractable problems in both verifiability and confirmability, Popper intended falsifiability, not as a criterion of meaning like verificationism (as commonly misunderstood), [24] but as a criterion to demarcate scientific statements from non-scientific statements. [9]
Notably, the falsifiability criterion would allow for scientific hypotheses (expressed as universal generalizations) to be held as provisionally true until proven false by observation, whereas under verificationism, they would be disqualified immediately as meaningless. [9]
In formulating his criterion, Popper was informed by the contrasting methodologies of Albert Einstein and Sigmund Freud. Appealing to the general theory of relativity and its predicted effects on gravitational lensing, it was evident to Popper that Einstein's theories carried significantly greater predictive risk than Freud's of being falsified by observation. Though Freud found ample confirmation of his theories in observations, Popper would note that this method of justification was vulnerable to confirmation bias, leading in some cases to contradictory outcomes. He would therefore conclude that predictive risk, or falsifiability, should serve as the criterion to demarcate the boundaries of science. [25]
Though falsificationism has been criticized extensively by philosophers for methodological shortcomings in its intended demarcation of science, [17] it would receive acclamatory adoption among scientists. [18] Logical positivists too adopted the criterion, even as their movement ran its course, catapulting Popper, initially a contentious misfit, to carry the richest philosophy out of interwar Vienna. [24]
In 1967, John Passmore, a leading historian of 20th-century philosophy, wrote, "Logical positivism is dead, or as dead as a philosophical movement ever becomes". [4] Logical positivism's fall heralded postpositivism, where Popper's view of human knowledge as hypothetical, continually growing and open to change ascended [24] and verificationism, in academic circles, became mostly maligned. [3]
In a 1976 TV interview, A. J. Ayer, who had introduced logical positivism to the English-speaking world in the 1930s [26] was asked what he saw as its main defects, and answered that "nearly all of it was false". [4] However, he soon said that he still held "the same general approach", referring to empiricism and reductionism, whereby mental phenomena resolve to the material or physical and philosophical questions largely resolve to ones of language and meaning. [4] In 1977, Ayer had noted: [3]
"The verification principle is seldom mentioned and when it is mentioned it is usually scorned; it continues, however, to be put to work. The attitude of many philosophers reminds me of the relationship between Pip and Magwitch in Dickens's Great Expectations . They have lived on the money, but are ashamed to acknowledge its source."
In the late 20th and early 21st centuries, the general concept of verification criteria—in forms that differed from those of the logical positivists—was defended by Bas van Fraassen, Michael Dummett, Crispin Wright, Christopher Peacocke, David Wiggins, Richard Rorty, and others. [3]
Falsifiability is a deductive standard of evaluation of scientific theories and hypotheses, introduced by the philosopher of science Karl Popper in his book The Logic of Scientific Discovery (1934). A theory or hypothesis is falsifiable if it can be logically contradicted by an empirical test.
Logical positivism, later called logical empiricism, and both of which together are also known as neopositivism, is a movement whose central thesis is the verification principle. This theory of knowledge asserts that only statements verifiable through direct observation or logical proof are meaningful in terms of conveying truth value, information or factual content. Starting in the late 1920s, groups of philosophers, scientists, and mathematicians formed the Berlin Circle and the Vienna Circle, which, in these two cities, would propound the ideas of logical positivism.
Philosophy of science is the branch of philosophy concerned with the foundations, methods, and implications of science. Amongst its central questions are the difference between science and non-science, the reliability of scientific theories, and the ultimate purpose and meaning of science as a human endeavour. Philosophy of science focuses on metaphysical, epistemic and semantic aspects of scientific practice, and overlaps with metaphysics, ontology, logic, and epistemology, for example, when it explores the relationship between science and the concept of truth. Philosophy of science is both a theoretical and empirical discipline, relying on philosophical theorising as well as meta-studies of scientific practice. Ethical issues such as bioethics and scientific misconduct are often considered ethics or science studies rather than the philosophy of science.
Otto Karl Wilhelm Neurath was an Austrian-born philosopher of science, sociologist, and political economist. He was also the inventor of the ISOTYPE method of pictorial statistics and an innovator in museum practice. Before he fled his native country in 1934, Neurath was one of the leading figures of the Vienna Circle.
Rudolf Carnap was a German-language philosopher who was active in Europe before 1935 and in the United States thereafter. He was a major member of the Vienna Circle and an advocate of logical positivism.
The Logic of Scientific Discovery is a 1959 book about the philosophy of science by the philosopher Karl Popper. Popper rewrote his book in English from the 1934 German original, titled Logik der Forschung. Zur Erkenntnistheorie der modernen Naturwissenschaft, which literally translates as, "Logic of Research: On the Epistemology of Modern Natural Science"'.
The Vienna Circle of logical empiricism was a group of elite philosophers and scientists drawn from the natural and social sciences, logic and mathematics who met regularly from 1924 to 1936 at the University of Vienna, chaired by Moritz Schlick. The Vienna Circle had a profound influence on 20th-century philosophy, especially philosophy of science and analytic philosophy.
Naïve empiricism is a term used in several ways in different fields.
In philosophy of science and in epistemology, instrumentalism is a methodological view that ideas are useful instruments, and that the worth of an idea is based on how effective it is in explaining and predicting natural phenomena. According to instrumentalists, a successful scientific theory reveals nothing known either true or false about nature's unobservable objects, properties or processes. Scientific theory is merely a tool whereby humans predict observations in a particular domain of nature by formulating laws, which state or summarize regularities, while theories themselves do not reveal supposedly hidden aspects of nature that somehow explain these laws. Instrumentalism is a perspective originally introduced by Pierre Duhem in 1906.
Critical rationalism is an epistemological philosophy advanced by Karl Popper on the basis that, if a statement cannot be logically deduced, it might nevertheless be possible to logically falsify it. Following Hume, Popper rejected any inductive logic that is ampliative, i.e., any logic that can provide more knowledge than deductive logic. This led Popper to his falsifiability criterion.
In philosophy of science and epistemology, the demarcation problem is the question of how to distinguish between science and non-science. It also examines the boundaries between science, pseudoscience and other products of human activity, like art and literature and beliefs. The debate continues after more than two millennia of dialogue among philosophers of science and scientists in various fields. The debate has consequences for what can be termed "scientific" in topics such as education and public policy.
Postpositivism or postempiricism is a metatheoretical stance that critiques and amends positivism and has impacted theories and practices across philosophy, social sciences, and various models of scientific inquiry. While positivists emphasize independence between the researcher and the researched person, postpositivists argue that theories, hypotheses, background knowledge and values of the researcher can influence what is observed. Postpositivists pursue objectivity by recognizing the possible effects of biases. While positivists emphasize quantitative methods, postpositivists consider both quantitative and qualitative methods to be valid approaches.
The deductive-nomological model of scientific explanation, also known as Hempel's model, the Hempel–Oppenheim model, the Popper–Hempel model, or the covering law model, is a formal view of scientifically answering questions asking, "Why...?". The DN model poses scientific explanation as a deductive structure, one where truth of its premises entails truth of its conclusion, hinged on accurate prediction or postdiction of the phenomenon to be explained.
Positivism is a philosophical school that holds that all genuine knowledge is either true by definition or positive –meaning a posteriori facts derived by reason and logic from sensory experience. Other ways of knowing, such as intuition, introspection, or religious faith, are rejected or considered meaningless.
Language, Truth and Logic is a 1936 book about meaning by the philosopher Alfred Jules Ayer, in which the author defines, explains, and argues for the verification principle of logical positivism, sometimes referred to as the criterion of significance or criterion of meaning. Ayer explains how the principle of verifiability may be applied to the problems of philosophy. Language, Truth and Logic brought some of the ideas of the Vienna Circle and the logical empiricists to the attention of the English-speaking world.
The problem of religious language considers whether it is possible to talk about God meaningfully if the traditional conceptions of God as being incorporeal, infinite, and timeless, are accepted. Because these traditional conceptions of God make it difficult to describe God, religious language has the potential to be meaningless. Theories of religious language either attempt to demonstrate that such language is meaningless, or attempt to show how religious language can still be meaningful.
Inductivism is the traditional and still commonplace philosophy of scientific method to develop scientific theories. Inductivism aims to neutrally observe a domain, infer laws from examined cases—hence, inductive reasoning—and thus objectively discover the sole naturally true theory of the observed.
An index list of articles about the philosophy of science.
This is a list of articles in analytic philosophy.
The descriptive fallacy refers to reasoning which treats a speech act as a logical proposition, which would be mistaken when the meaning of the statement is not based on its truth condition. It was suggested by the British philosopher of language J. L. Austin in 1955 in the lectures now known as How to Do Things With Words. Austin argued that performative utterances are not meaningfully evaluated as true or false but rather by other measures, which would hold that a statement such as "thank you" is not meant to describe a fact and to interpret it as such would be to commit the descriptive fallacy.