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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.
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,
Logical positivism was not only interested in pure
philosophical research, but also in political and educational activity.
The ideas of its members were progressive, liberal and
sometimes socialist. But in 1933 Hitler became Chancellor of Germany;
Nazism was hostile towards neopositivism.
The basic tenets of logical positivism are that there are exactly 2 ways to
know truth, and 1 false way:
- Analytic a priori: Math statements like 2 + 2 = 4.
- Synthetic a postiori: Science statements like "all crows are black"
- 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