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Lecture 18: Positivism

Positivism has both a narrow and an expanded definition. In its narrow definition, it describes the philosophy of the Vienna and Berlin Circles, which in the 1920's attempted to rationalize not just philosophy, but all the sciences, based on a strict set of rules. In its wider definition, positivism is the belief that all of science is a steady upward progress that can be assisted by following the rules. As a strict philosophy, positivism had a brief life in the first half of the 20th century, but its impact can still be seen in the religion vs science debates continuing up to today.

Vienna Circle

The philosophers that collected in Vienna in the 1920's included Moritz Schlick, who was asassinated by a Nazi in 1936, and it was the ascendance of the Nazi party which scattered his colleagues, Rudolf Carnap, Hans Reichenbach and Carl Gustav Hempl to America, where there influence was perhaps greater than in Europe. The Vienna circle began under the influence of Ernst Mach's (1838-1916) views on science and metaphysics, calling itself, "The Ernst Mach Society". Mach had been both a first-rate physicist and anti-realist, radical empiricist philosopher who disliked the Newtonian metaphysics. With Einstein's breakthrough of special relativity (and his lectures on what science really measures), there finally appeared to be a good reason to abandon Newton's metaphysics. For Mach, the error lay in assuming the existence of something we can't see or prove, Newton's insistence on absolute space and time. Thus to avoid Newton's errors, we must not allow ourselves to predict or believe in a "reality behind" the observations. Mach wanted to remove the dependence on metaphysics from the pursuit of science. For the Vienna circle, this desire was realized in the techniques and skills being developed by Russell among others in symbolic logic, and the new-found ability to subject language to the rigors of mathematics. With the principle at heart and techniques in hand, they began to construct what such a scientific, metaphysic-free, world would look like.

However, there are other motivating factors in the development of logical positivism. One factor is the belief that all the ills of the preceding centuries, and in particular, the ills caused by religion, were the result of bad metaphysics. Heaven and hell, for example, should be seen as unprovable constructs that must be abandonned in the name of good science. Furthermore, true heaven would be the concrete realization of peace and prosperity that resulted from scientific progress, the inevitable result of applying scientific methods to everyday life. Russell, a british philosopher who was part of the program, and also influenced the Vienna circle, wrote a book in 1927 entitled, "Why I am not a Christian", which clearly tied this philosophy to an atheistic world view. One way to view logical positivism is as an increasing secularization of science in the same spirit as Darwin; Kant's wall between religion and science became a shrinking boundary around a religious ghetto. To quote the internet encyclopedia of philosophy,
The basic tenets of logical positivism are that there are exactly 2 ways to know truth, and 1 false way:
  1. Analytic a priori: Math statements like 2 + 2 = 4.
  2. Synthetic a postiori: Science statements like "all crows are black"
  3. Synthetic a priori: Science statements like "Invisible atoms are responsible for the laws of gases (PV=nRT).
A statement has meaning if and only if one can logically verify it. Since synthetic a priori cannot be verified, they have no meaning. By detecting and removing the false synthetic a priori, we can purge our science and religion of all sorts of outdated and dangerous concepts like "souls" or "God". Unfortunately, there were a number of problems with this view, because lots of useful theories could never be based on these two acceptable techniques. That is, one cannot prove that all of math is based on step-by-step construction of a priori truthful statements. There were some perfectly reasonable mathematical statements that were neither true nor false. Nor is it fair to dismiss most accepted models in science, just because they use a synthetic a priori.

The Vienna circle influenced people like Kurt Goedel, Karl Popper, and Ludwig Wittgenstein who all responded to its siren song in different ways. Popper, for example, argued with the Vienna circle about their "verification" principle, saying that it was more accurate to say that a model should have ways to falsify it. E.g., a Freudian theory that always explained everything in the end explained nothing. Better a theory that delimited itself by saying in effect "if you make this observation then my theory is false." Popper attributes this insight to Einstein, who said the 1919 eclipse expedition was a chance to falsify his theories. (Curiously, this aspect of positivism has been used against Evolution for being a unfalsifiable theory, to which proponents sniff that this is "Popper chopping".) Even this rescusitation was too limiting, and in the end, no philosopher of science today will attempt to defend strict positivism.

Characteristic of this change, Ludwig Wittgenstein, Bertrand Russell's brightest student, wrote a very significant support of positivism known as the Tractatus Logico-Philosophicus in which he delineates the project of positivism in terms of language. But a few years later after attempts to build such a world view, he reverses himself in The Blue and Brown Books" and his posthumous Philosophical Investigations in which he argues that truth cannot be so easily confined in language, rather it is localized to the little world under discussion, or "language game". This conclusion founded the field of "analytic philosophy" wherein philosophers no longer attempt to find absolute truth, but uncover the rules of a particular language game.

Kurt Goedel, who came to Princeton during WWII, wrote a mathematical proof using symbolic logic, illustrating why ambiguity was unavoidable. This was a great blow to the program. For years, Russell and Whitehead had been collaborating on an encyclopaedia " Principia Mathematica which intended to demonstrate that all mathematics could be based on the simple Peano assumptions plus logic alone. But can logic always determine the truth of a mathematical statement? Russell gives the brain puzzler "Suppose in a certain small town there is a barber who shaves everyone who does not shave himself. Who shaves the barber?" (My favorite answer is "She doesn't need to.") One can distill that story into the proposition "This statement is false." Is that a true or false sentence? Russell goes to great lengths to exclude such nonsense from his philosophy, but Kurt Goedel's proof demonstrated that self-referential statements were the bane of logic, and could never be excluded. i.e. if Russell will make a rule to exclude such statements, Goedel will include that rule in his new version. Thus any language Russell can invent will never be completely self-consistent, it can never categorically demonstrate the truth or falsehood of every theorem, it will be always incomplete, it will always need "outside help" to determine meaning. Douglas Hofstetter, in his book Goedel, Escher, Bach points out that self-referentiality has important consequences. For example, AIDS is a virus that infects the body's anti-virus machinery, with devastating results. We will discuss later in the course why self-referentiality has important theological ramifications as well.

One last story of the demise of positivism is worth telling. Rudolf Carnap came to America to escape the Nazis and had a long and successful career beginning at the University of Chicago. He persuaded a student, Thomas Kuhn, to write an article for the International Encyclopaedia of the Unified Sciences on scientific theory development, probably believing that it would illustrate the principles of logical positivism. Instead, Kuhn discovered that science progresses not at all logically, and his article became the book "The Structures of Scientific Revolution", which ironically sounded the death knell for an optimistic positivism view of scientific progress. That is, not only does positivism fail in principle, as Goedel and Wittgenstein argued, it failed in practice, as Kuhn showed.

Thus logical positivism failed to accomplish its noble goals of firmly establishing all of science and life on simple logic and observation. For many people including most scientists, this failure was percieved as a limitation of the tools, not of the stated goals. That is, the goal of secularization was still valid, only the approach required some more tinkering. If I can make a generalization, this reduced intensity positivism became a widespread article of faith in "materialistic naturalism" that finds so much expression in our schools and academies today. Contrast this view with that of Wittgenstein who completely forsook any attempt for logical proof of absolute truth. This paradox, that scientists continue to believe in the search for absolute truth while philosophers have abandonned it, lies at the heart of the dilemma facing the current, post-modern culture. Once again, it appears that epistemology is crucial to understanding our present impasse. Whether it be theology, science or philosophy, whether it be metaphysics or ethics, it appears that Pilate's question, "What is Truth?" remains basic.
Last modified, March 4, 2002, RbS