Science and Logical Positivism: Why Logical Positivism Fails?
What is scientific method? What makes it valid? After the end of the WWI, a group of philosophers began meeting in Vienna to discuss the implications of the development in logic. They broadly supported logical positivism which combines empiricism with rationalism incorporating mathematical and logico-linguistic constructs and deductions of epistemology. Mainly, logical positivists held the criterion of verification to examine the validity of science.
In this article, I will examine the basic idea of how logical positivists examine the scientific theories.
The Vienna Circle and Logical Positivism
In 1931, a group of philosophers, namely The Vienna Circle, claim that although logic is a very important tool in philosophical analysis, the philosophical problems are either meaningless or are to be analyzed in logical terms. In other words, they see continental philosophy as meaningless and analytic philosophy as meaningful because they believe that metaphysical claims are cognitively empty and have no meaning.
The Vienna Circle holds logical positivism view to reject metaphysics by means of the Verification Principle. Which is, the meaning of a proposition is the method of its verification. The idea is that all significant propositions could be reduced to statements about sense experiences or observations. In particular, terms in the vocabulary of theoretical terms have meaning only insofar as they can be transformed to terms in vocabulary of observation terms. For example, A white streak in a cloud chamber is an electron. Such connection between theoretical and observation terms calls Bridge Principles.
The Verification Principle wants to show two things: (1) Meaning and (2) Knowledge. First, this principle can guarantee the concepts that we are using are meaningful and not only appear to be so. Second, all our knowledge about the world can be based on sense experiences and observation.
The Nature of True Propositions
Logical positivists held the view that propositions are either analytic or synthetic.
(a) Analytic proposition has various definition but the most popular definition is that true in virtue of their meaning. An analytic proposition is true in virtue of the meanings of the words it contains. For example, bachelor is an unmarried man is true in virtue of the meanings of the words bachelor, unmarried man, and is. We do not have to check whether all bachelors in the world are unmarried men. This proposition is necessarily true, and it can be known to be so a priori.
(b) A synthetic statement is true in virtue of the way the world is. For example: there are over 1000 words in this articles. The truth of this proposition is necessary. It is a contingent matter.
What makes logical positivism fail? (1) Universal Proposition
In fact, a scientific theory contains universal statements such as all ravens are black and every action has an equal and opposite reaction. Such universal claims cannot be verified. To verify the proposition all ravens are black, we have to examine every single raven that is included those one in the past and those one in the future. Namely, they are not verifiable in principle because no finite number of observation can verify them.
Many of them tried to develop an inductive logic of confirmation. However, Karl Popper argues that the scientific knowledge should be only based on justified reasoning. While inductive logic of confirmation cannot give a justified reasoning, scientific method and knowledge should not be based on induction.
What makes logical positivism fail? (2) Science and Non-Science
Another problem that logical positivists face is the criterion between science and non-science. According to Karl Popper, the verification principle is both too narrow and too wide. It is too wide to allow for theories such as Marxism and psychoanalytic to count as science.
Marxism used to be scientific because it made predictions and they could be rejected. However, Marxists kept changing the theory, and it turned out that this theory could explain every event and could not be falsified. Similarly with Marxism, psychoanalytic theories explain human behaviours in terms of unconscious desires. In fact, these theories can explain any behaviour by referring to the same unconscious desires. If we accept a pyschoanalyst's interpretation of our behaviour, this is a confirmation. If we reject it, it is also regarded as a confirmation (For example, we are too afraid to admit our real unconscious desires).
Popper believes that it is illegitimate to accept these theories as science because these theories does not give us information about the world.
The verification principle is too narrow because it is doubtful that unobservable entities such as electrons and photons actually be verified or reduced to direct sense experience. If I say, "Electrons are elementary particles, " there is no direct observation that can verify. However, these theories make risky predictions that can be tested. While the verification principle attempts to show whether theories are meaningful or not, it does not provide a good distinction between science and non-science.
What makes logical positivism fail? (3) History of Science
Logical positivists believes that history of science has been cumulative. While science is more concerned with the observable part, history of science is only a history of our empirical knowledge. It implies that there no scientific revolutions because later scientific theories do not replace earlier scientific theories. For example, Newton's gravitation theory can explain Kepler's laws. Kepler's theory is reducible to Newton's theory. So, we have a kind of Russian doll model to explain history of science. While the older theories (smaller dolls) contain in later theories (bigger dolls) that are contained in yet future theories.
However, I do not think it is true at all. Although Newton's theory of gravity gives a unified account of the motions of the planets, Einstein's general relativity has totally introduced new idea to explain the motions of the planets, and it does not replace the Newton's earlier theory of gravity at all. Similarly, Thomas Kuhn totally rejects logical positivist view of history of science in his Structure of Scientific Revolutions. There are numbers of significant revolutions that overturned earlier scientific theories. He believes that science cannot be cumulative, but it is revolutionary. When Einstein introduced his general relativity, it is not merely a complex version of Newton's theory. General relativity has its direction, and there is "no coherent director of ontological development" for puzzle-solving.
Indeed, logical positivism has attempted to show that what makes science valid. Although it is true to say that to explain phenomenon scientifically should be both empirical and meaningful, it dismisses the metaphysical and normative pretensions of philosophical tradition. This explanation also leads to say that some phenomena such as electrons and black holes are invalid because they cannot be directly observed. Logical positivists also cannot provide a controversial account to explain history of science. Typically the explanation of Einstein's general relativity and Newton's theory of motions both lead to their own but different directions. Logical positivism was indeed once dominated in philosophy of science for many years. But, other doctrines appeal to have better explanation; it causes this view becomes one of the historical movement.