Karl Popper was an influential 20th century philosopher best known for his rejection of the idea that science aims to verify theories. He argued that science progresses through bold conjectures being subjected to attempts at falsification, not verification. Popper also believed in fallibilism, the idea that all knowledge is conjectural and subject to revision. He developed the concept of critical rationalism, which uses criticism to eliminate errors in theories and progress toward the truth. Popper analyzed the differences between open and closed societies and advocated for piecemeal social engineering over utopian attempts to reshape society.

1. The Philosophy of Karl Raimund
Popper
"We have to learn the lesson that intellectual honesty
is fundamental for everything we cherish".

2.  Popper is a systematic philosopher with wide-
ranging interests.
 He is a critical fallibilist (imperfectionist) in
epistemology and an anti-perfectionist in politics.
 His ontology is based on the idea that there are
three worlds, the first of material entities, the second
of subjective minds and the third of objective
knowledge.
 He wrote very little about education directly yet his
work has interested philosophers of education
working on such diverse topics as
 the relationship between theory and practice,
 the nature of science education,
 learning theory, political philosophy, critical thinking,
 problem-solving and social and organisational
change.

3.  What is critical rationalism?
 "Critical Rationalism" is the name given to a
strand of philosophy that considers the nature of
problems and their solutions. It encourages a
style of thinking that addresses real problems in
a practical way, leading to real solutions.
 The main Questions addressed are
 1. How do we know what we know, and how can
we tell whether it is true or not?
 2. What is the best way to solve problems?
 "Problems" is used in a wide sense here: you
are in a given situation, and you would like to
change it. Life, in this sense, is series of
problems, and so is the acquisition of new
knowledge.

4.  Karl Popper ‘s philosophy reveals through his
works
 First one is The Logic of Scientific Discovery ,1934
 Although scientific theories cannot be verified or
even rendered probable by evidence, they can be
falsified. Science makes progress by putting
forward falsifiable conjectures.
 When a scientific theory is falsified empirically, the
task then becomes to think up an even better
theory.
 The new theory must predict all the success of the
old theory, predict successfully the phenomena that
falsified the old theory, and predict new phenomena

5.  In The Poverty of Historicism
Demolishes the view that social science can
predict the way how societies evolve.
 The Logic of Scientific Discovery
Deals how the view of social science should
be developed like that of natural science.

6.  The Open Society and Its Enemies
 Popper argues that a fundamental problem confronting
humanity is that of moving from a closed, tribal way of life
to an open society.
 The closed society is a society that has just one view of the
world, one set of values, one basic way of life. It is a world
dominated by dogma, fixed taboos and magic, devoid of
doubt and uncertainty.
 The open society, by contrast, tolerates diversity of views,
values and ways of life.
 In the open society learning through criticism is possible
just because diverse views and values are tolerated. For
Popper, the open society is the civilized society, in which
individual freedom and responsibility, justice, democracy,
humane values, reason and science can flourish.

7.  Conjectures and Refutations, is a collection of
essays which restate alsification in a more
accessible way.
 Objective Knowledge, draws on the analogy
between Darwinian evolution and scientific
progress
 There exists, in addition to the material world and
the psychological world, a third world of theories,
problems and arguments
 The Self and Its Brain, written with the neurologist
John Eccles applies Popper's "third world" view
to the mind-body problem.
 Three volumes of The Postscript deals with the

8.  Two issues were of central concern to Popper.
 The first was the problem of how to
distinguish science from pseudo-science.
 Popper was impressed by the difference
between the theories of Marx, Freud and Adler
on the one hand, and Einstein's general theory
of relativity, on the other.
 The former theories seemed able to explain
phenomena and nothing could tell against
these theories.

9.  Einstein's theory, by contrast, issued in a
definite prediction; light travelling near the sun
would pursue a curved path due to the
gravitational field of the sun. If this did not
happen, Einstein's theory would be refuted.

 Popper considered that this constituted the
key difference between pseudo and genuine
scientific theories: whereas the former were
unrefutable, the latter were open to empirical
refutation.

10.  The other problem that preoccupied Popper
was the logic, or methodology, of scientific
discovery:
 How does science acquire new knowledge?
 How this can be adopted for the advent of
social theories?


11.  Moving from the closed to the open society imposes a great
psychological burden on the individuals involved, "the strain of
civilization".
 Instead of the security of the tribe, organic, dogmatic and
devoid of doubt, there is all the uncertainty and insecurity of
the open society, the painful necessity of taking personal
responsibility for one's life in a state of ignorance, the lack of
intimacy associated with the "abstract society" in which
individuals constantly rub shoulders with strangers.
 This transition, from the closed to the open society is, for
Popper, "one of the deepest revolutions through which
mankind has passed.
 Many cannot bear the burden of freedom and doubt, and long
for the false security and certainties of the closed society.
 Some of the greatest thinkers like Plato and Aristotle in more
recent times, Hegel and Marx have done this.

12.  Unrestricted capitalism of Marx's time has subsequently
become both more economically successful and more just and
humane as a result of diverse political interventions.
 It is also too easy to suppose that the new political leaders
would seize and hold onto power, justifying this by exploiting
and twisting the revolutionary ideology and by invoking the
threat of counter-revolutionary forces.
 Marx's economic historicism is not just false; it is pseudo-
scientific. Long-term prediction is possible only for
exceptionally simple systems.
 In the case of social systems, incredibly complex and open to
the influence of a multitude of unpredictable factors, the idea
that science should be able to deliver long-term predictions is
hopelessly unwarranted

13.  According to Karl Popper
 Both scientific method and rationality need to be
understood in social terms.
 It should not be imagined that a study of the past will
enable the future to be predicted with any reliable degree
of certainty.
 Using utopian social engineering to attain an ideal social
order, such as socialism is a failure. Instead a ‘piecemeal
social engineering’ process that searches for and fights
against the greatest and most urgent evils of society is
to be sought for constantly.

14.  Science makes progress by proposing bold
conjectures in response to problems, which are then
subjected to sustained attempted empirical refutation.
 This falsificationist conception of scientific method is
then generalized to form a general methodology for
solving problems or making progress.
 This is refered to as critical rationalism.

15.  CRITICAL RATIONALISM can be understood, in Popper’s
own words, as admitting that,
 ‘I may be wrong and you may be right’, and that
 ‘by an effort, we may get nearer to the truth’.
 We have to think
 negative about positives and
 positive about negatives and turn the
 conformation of truths to falsification of generalisations.
 By this he refutes the utopian idea of
“ Ultimate Solution of Problems”

16.  Three Core Concepts of Critical Rationalism
 Critical Rationalism is an effort by which we discover a
problem, propose a theory as a tentative solution, implement
the theory to eliminate errors that we find in it, and by
eliminating those errors we progress to the discovery of a new
problem.
 The three core concepts of critical rationalism are
 FALLIBILISM, CRITICISM & VERISIMILITUDE.

17.  FALLIBILISM
 Popper argued that
 What was once substantiated historically by fact may later turn
out to be false.
 Our scientific knowledge is fallible because we cannot ‘justify’
our theories by showing that they are always and actually true.
 In addition, there is also the limitation of our ability to predict
the future course of history, not because of our inability to
predict the future growth of human knowledge, but because
such a thing as growing human knowledge, then we cannot
anticipate today what we shall know only tomorrow.
 Thus, his fallibilism disregards authoritative sources of
knowledge. Instead, he argues that nothing is secure and that
our knowledge is conjectural and fallible.

18.  CRITICISM
 Since we learn from our mistakes, fallibilism should not lead to
skeptical or relativist conclusions.
 Popper claims that criticism is the only way we have of
detecting our mistakes, and of learning from them in a
systematic way.
 Criticism includes criticising the theories or conjectures of
others and of our own. It consists of deductive logical reasoning
to remove inconsistencies from our theories, modify or refine
or replace our theories when they do not do what they are
intended to do or when contradictions occur.
 Popper rejected all attempts to justification of theories; instead
he replaced justification with criticism.

19. VERISIMILITUDE
getting closer to the truth
 Popper regarded the search for verisimilitude rather than
truth as a more realistic aim of science because while we
cannot have sufficiently good arguments for claiming that
we have attained the truth, we can have good arguments
for claiming that we have made progress towards the truth.
 In other words, P2 is epistemicaly more progressive than
its predecessor P1 and therefore it is preferred.
P1 ---> TT ---> EE ---> P2

20. Popper’s Three Worlds
According to Popper individuals engage with their
surroundings on three levels.
World 1
Physical world or the world of physical states
World 2
Mental world or the world of mental states
World 3
World of ideas
It is a world of possible objects of thought:
the world of theories in themselves and their logical
relations; of arguments in themselves ;
and of problem situations in themselves.

21. The three Worlds are so interrelated that
the first two can interact and the last two can interact.
We can say that the second world, which is the world of
subjective or personal experiences, interacts with
each of the other two Worlds.
The first and third Worlds cannot interact; they can only
do so through the intervention of the second World,
the world of subjective or personal experiences.
In other words, the second World acts as a mediator
between the first and the third.