Philosophy - EXAM - May 23, 2019
Lecture 6 - Chapter 7
Karl Popper
Philosophy of science
- Philosophers looked for foundation of knowledge (up until WW2, Vienna Circle), foundational
epistemology = real knowledge is only possible if it stands on a foundation of certain and
necessary principles
- Logical positivism: source of knowledge is science, shift from philosophy of knowledge to
philosophy of science, combining empiricism with modern logic
- Karl Popper as critic of logical positivism: he agreed with the importance of logic and
mathematics for science and appreciated emphasis on empirical testing, but felt like they
missed the rational aspect to knowledge and science which he considered of fundamental
importance, for Popper theory always comes before observation
- Popper: new direction of philosophy, fallibilist epistemology = our understanding of reality is
fallible (error prone), scientific knowledge can be more or less conformed but it cannot be
guaranteed to be free of error
- Popper as proponent of rationalism (= the practice or principle of basing opinions and actions
on reason and knowledge rather than on religious belief or emotional response), but very critical
rationalism
Popper’s encounter with Marxism
- Made him think what determines the scientific character of a theory (Marxist theory and
scientific theories)
- Learned that humans are liable to make mistakes, humans are fallible (= prone to make
mistakes/errors) creatures; learned that there is a significant difference between dogmatic
theories (like the Marxist theory) and critical thinking
- If a theory is able to explain all the relevant data and if it is allegedly supported by an incessant
stream of confirmations, this in fact a vice and not a virtue
Popper meets Alfred Adler
- Adler was a disloyal member of Sigmund Freud’s psychoanalytic movement, developed a
theory called ‘Individualitätspsychologie’ leading to the concept of the ‘inferiority complex’ (=
lack of self-esteem and feelings of not measuring up to standards, often subconscious)
- Popper confronted Adler with a case that seemed unexplainable by Adler’s theory, but he could
explain it and was sure of it, Popper asked him how, Adler said through his experience
- Popper started realizing that, just like Marxism, these are theories that were capable of
explaining everything (also like astrology)
- Felt like unlimited explanatory power was not a strength but a sign of unscientific character of
such theories
,Popper on Marx and Adler
- Their formulation makes them always right
- They adjust the theory after observations
- Their theory explains everything
- That cannot be scientific says Popper
Popper and the bending of light
- There were two theories about the bending of light: Newton’s and Einstein’s
- Eddington and other British scientists wanted to test theories and decide which one is correct,
did that during solar eclipse of 1919
- The data showed that perditions based on Newton’s theory were wrong and predictions on
Einstein’s theory were right
- Showed Popper how real science is conducted and made him doubt the scientific status of
theories (as those of Adler and Marx)
The problem with verification
- Confirming evidence can be perceived everywhere, if you believe in something (also
conspiracies) you find conformation everywhere
- The empirical base of verification is either certain but subjective (phenomenalism) or
intersubjective but not certain (physicalism)
- Vienna Circle did not solve the problem about the foundation if scientific statements
- Also, two branches of verification
- Phenomenalism: certain but subjective (I am certain my bottle is blue but someone else
might see it as something else) (mental eye)
- Tie theoretical statements to protocol sentences about sensory experiences (phenomenal
language); verification is personal and comes directly with the statement: certain but
subjective (n=1, ‘I’); compare (test) these to reality (truth is correspondence of facts with
reality); problematic with statements about pain, fear etc.
- Physicalism: intersubjective but not certain (We agree that my bottle is blue but it might not
be) (bodily eye)
- Tie theoretical statements to protocol sentences about the physical world, observable
material objects (physical language); verification is intersubjective but not certain (n>1,
‘we’); compare statements with other statements (truth is a coherent system of
statements); problematic because it can lead to relativism: anything goes as long as it’s a
coherent story
, Popper’s new idea
- Because the boundary between science and non-science is not clear
- Empiricist solutions don’t work good enough: verification too strong, conformation too weak
- Verification: a complete and definitive establishment of the truth; is never possible as you
cannot observe everything, it’s impossible to check each and every instance
- Schlick’s response: theories are not the absolute truth but an instrument to predict; universal
laws are neither true nor false, they are more of a rule or guideline used to generate predict e.g.
‘All metals expand when heated’ has no truth value but is a statement used to predict that this
particular piece of iron will expand when heated
- Verification considered oversimplified, Carnap proposed modification of it, attempt to increase
a statement’s degree of confirmation; verifiability replaced by confirmability
- Confirmation: a theory must be in agreement with established facts; partial verification or
degree of confirmation (Carnap’s solution), perfect confirmation = 1, no confirmation = 0
- Every white swan that I observe counts as an empirical confirmation of my theory that all
swans are white, with every sighting of a white swan the degree of confirmation of the theory
increases
- Popper: verification is to weak as a criterion of demarcation, supports pseudosciences such as
astrology too much
- Popper’s new idea: falsifiability; any legitimate scientific theory will make predictions that can in
principle be falsified, scientific statements must be capable of conflicting with possible or
conceivable observations
- Does not demand that a theory should actually be falsified, it is the possibility of falsification
that is important, an active search for refuting evidence of a statement/theory is the heart if the
scientific method
- Four main aspects of falsificationism
- (1) Falsification is an adequate criterion of demarcation
- (2) Only theories that can be falsified are informative
- (3) Humans are fallible, we are seekers for truth
- (4) Knowledge grows through conjectures and refutations, trial and error, deduction instead
of induction
- Knowledge grows through deduction (from general to specific reasoning) instead of induction
- e.g. theory: All swans are white
- Positivists look for specific cases (verification: white swans) and say all swans are white
- Popper says: ‘all swans are white’ is a working theory, necessary to look for specific cases
(falsification: non white swans), if one is found, the theory is wrong and if not then the theory
is corroborated (deduction)
- Obviously the problem with deduction about the truth of the first premise, but Popper
believes that a theory can never be proven, therefore it works
Lecture 6 - Chapter 7
Karl Popper
Philosophy of science
- Philosophers looked for foundation of knowledge (up until WW2, Vienna Circle), foundational
epistemology = real knowledge is only possible if it stands on a foundation of certain and
necessary principles
- Logical positivism: source of knowledge is science, shift from philosophy of knowledge to
philosophy of science, combining empiricism with modern logic
- Karl Popper as critic of logical positivism: he agreed with the importance of logic and
mathematics for science and appreciated emphasis on empirical testing, but felt like they
missed the rational aspect to knowledge and science which he considered of fundamental
importance, for Popper theory always comes before observation
- Popper: new direction of philosophy, fallibilist epistemology = our understanding of reality is
fallible (error prone), scientific knowledge can be more or less conformed but it cannot be
guaranteed to be free of error
- Popper as proponent of rationalism (= the practice or principle of basing opinions and actions
on reason and knowledge rather than on religious belief or emotional response), but very critical
rationalism
Popper’s encounter with Marxism
- Made him think what determines the scientific character of a theory (Marxist theory and
scientific theories)
- Learned that humans are liable to make mistakes, humans are fallible (= prone to make
mistakes/errors) creatures; learned that there is a significant difference between dogmatic
theories (like the Marxist theory) and critical thinking
- If a theory is able to explain all the relevant data and if it is allegedly supported by an incessant
stream of confirmations, this in fact a vice and not a virtue
Popper meets Alfred Adler
- Adler was a disloyal member of Sigmund Freud’s psychoanalytic movement, developed a
theory called ‘Individualitätspsychologie’ leading to the concept of the ‘inferiority complex’ (=
lack of self-esteem and feelings of not measuring up to standards, often subconscious)
- Popper confronted Adler with a case that seemed unexplainable by Adler’s theory, but he could
explain it and was sure of it, Popper asked him how, Adler said through his experience
- Popper started realizing that, just like Marxism, these are theories that were capable of
explaining everything (also like astrology)
- Felt like unlimited explanatory power was not a strength but a sign of unscientific character of
such theories
,Popper on Marx and Adler
- Their formulation makes them always right
- They adjust the theory after observations
- Their theory explains everything
- That cannot be scientific says Popper
Popper and the bending of light
- There were two theories about the bending of light: Newton’s and Einstein’s
- Eddington and other British scientists wanted to test theories and decide which one is correct,
did that during solar eclipse of 1919
- The data showed that perditions based on Newton’s theory were wrong and predictions on
Einstein’s theory were right
- Showed Popper how real science is conducted and made him doubt the scientific status of
theories (as those of Adler and Marx)
The problem with verification
- Confirming evidence can be perceived everywhere, if you believe in something (also
conspiracies) you find conformation everywhere
- The empirical base of verification is either certain but subjective (phenomenalism) or
intersubjective but not certain (physicalism)
- Vienna Circle did not solve the problem about the foundation if scientific statements
- Also, two branches of verification
- Phenomenalism: certain but subjective (I am certain my bottle is blue but someone else
might see it as something else) (mental eye)
- Tie theoretical statements to protocol sentences about sensory experiences (phenomenal
language); verification is personal and comes directly with the statement: certain but
subjective (n=1, ‘I’); compare (test) these to reality (truth is correspondence of facts with
reality); problematic with statements about pain, fear etc.
- Physicalism: intersubjective but not certain (We agree that my bottle is blue but it might not
be) (bodily eye)
- Tie theoretical statements to protocol sentences about the physical world, observable
material objects (physical language); verification is intersubjective but not certain (n>1,
‘we’); compare statements with other statements (truth is a coherent system of
statements); problematic because it can lead to relativism: anything goes as long as it’s a
coherent story
, Popper’s new idea
- Because the boundary between science and non-science is not clear
- Empiricist solutions don’t work good enough: verification too strong, conformation too weak
- Verification: a complete and definitive establishment of the truth; is never possible as you
cannot observe everything, it’s impossible to check each and every instance
- Schlick’s response: theories are not the absolute truth but an instrument to predict; universal
laws are neither true nor false, they are more of a rule or guideline used to generate predict e.g.
‘All metals expand when heated’ has no truth value but is a statement used to predict that this
particular piece of iron will expand when heated
- Verification considered oversimplified, Carnap proposed modification of it, attempt to increase
a statement’s degree of confirmation; verifiability replaced by confirmability
- Confirmation: a theory must be in agreement with established facts; partial verification or
degree of confirmation (Carnap’s solution), perfect confirmation = 1, no confirmation = 0
- Every white swan that I observe counts as an empirical confirmation of my theory that all
swans are white, with every sighting of a white swan the degree of confirmation of the theory
increases
- Popper: verification is to weak as a criterion of demarcation, supports pseudosciences such as
astrology too much
- Popper’s new idea: falsifiability; any legitimate scientific theory will make predictions that can in
principle be falsified, scientific statements must be capable of conflicting with possible or
conceivable observations
- Does not demand that a theory should actually be falsified, it is the possibility of falsification
that is important, an active search for refuting evidence of a statement/theory is the heart if the
scientific method
- Four main aspects of falsificationism
- (1) Falsification is an adequate criterion of demarcation
- (2) Only theories that can be falsified are informative
- (3) Humans are fallible, we are seekers for truth
- (4) Knowledge grows through conjectures and refutations, trial and error, deduction instead
of induction
- Knowledge grows through deduction (from general to specific reasoning) instead of induction
- e.g. theory: All swans are white
- Positivists look for specific cases (verification: white swans) and say all swans are white
- Popper says: ‘all swans are white’ is a working theory, necessary to look for specific cases
(falsification: non white swans), if one is found, the theory is wrong and if not then the theory
is corroborated (deduction)
- Obviously the problem with deduction about the truth of the first premise, but Popper
believes that a theory can never be proven, therefore it works
