Karl Popper (1902-1994)
was an Austro-British philosopher of science born in
Vienna, on July 28, 1902, to an upper middle class family. Although he
was of Jewish descent, his family converted to Lutheranism before he
Popper was educated at the University of Vienna where his father was a
doctor of Law. From his father he inherited both a love of books (he
left him over 12,000 volumes from his personal library) and a keen
interest in the classics, philosophy, and socio-political issues all of
which laid the groundwork for his future thinking.
At the University of Vienna, Popper earned his PhD with a thesis on the
nature of method in psychology which qualified him to teach physics and
mathematics in high school. While he was teaching, his thesis gained
the attention of a group of philosophers, mathematicians and physicists
(the Vienna Circle) who were instrumental in the logical positivist
movement during the 1920's and 1930's. With the group's help, he
published his first book The Logic of Scientific
. It was widely read and Popper was
invited to lecture at universities in the United States and Great
In The Logic of Scientific Discovery
Popper sets out the doctrine of falsificationism in which he attempts
to repudiate the classical observationalist form of scientific method.
In it he even claims to have solved Hume's
According to Popper, the point of a scientific theory is whether it
makes predictions which could in principle serve to falsify it. The
more predictions a theory makes, "the better it is." He calls this
falsification a response to the 'myth of induction'. Induction, as put
, is the method of arriving at theories, laws or
generalizations by observing regularities in experience.
is, however, that no number of observed cases in which some
possess property y elicits the conclusion that all
possess property y
. Therefore this
principle cannot be justified on either logical or experiential
Popper attempts to avoid the
problem of induction by arguing
that scientific rationality consists of the falsification of theories
than the inductive verification of them.
Instead of generalizations being characterized as conclusions
inferred from evidence, they can logically be considered conjectures.
They can be tentative hypotheses on trial in "the court of experience."
In this regard,
Hume's problem of induction disappears because
generalizations are not supported or justified by observation. Rather,
generalizations can either be refuted by experience (as when some x's
are found to lack y) or continue to await further
observations. Experience can never verify a theory to be true, it can
only falsify it. Generalizations first come about through conjecture
and are then held up to the scrutiny of experience to be refuted.
Thus, according to Popper, in experimental testing, no number of
positive outcomes can confirm a scientific theory, but a single
counterexample can imply it to be false. While the term 'falsifiable'
does not mean something is false, it does indicate that if it is false,
it can be demonstrated by observation or experiment.
Popper used falsifiability as his criterion to differentiate
between what is, and what is not, genuinely scientific. Consequently, a
theory should be considered scientific if, and only if, it is
falsifiable. Popper's falsifiablity resembled
Charles Peirce's fallibilism, which he purportedly wished to
have read about earlier in his career.
As well as being known for his self-described philosophy of critical
rationalism, Karl Popper was a vigorous defender of liberal democracy
and a social critic. In his book The Open Society and
Its Enemies (1945), Popper criticizes
Plato and his idea of philosopher-kings, and in the second
volume he tackles
Karl Marx, the rise of totalitarianism and what should be
done about it.
Ultimately, Karl Popper's influence has served to further promote
debate in the philosophy of science. It also helped give rise to the
works of Lakatos, Kuhn and Feyerabend.
Karl Popper remains a philosopher of considerable standing in the
fields of science, social and political thought, a dedicated opponent
of skepticism, conventionalism, and a staunch defender of the 'Open
Charles Sanders Peirce