What is Science

1
What is Science?

• Summary of lecture 1

2
Motivation

• Scientific knowledge is held in high regard, but
  can its status be justified?
• Is there a method for doing science that
  distinguishes it from other forms of
  investigating the world?
• Can we prove that the theories we produce using
  the scientific method provide a true description
  of reality?
• Is the concept of an objective reality
  sustainable?

3
A common view of science
Objective Reality independent of humanity
Theory
True Theory
There is no place for the human subject in this
picture
Our theory represents the world as it really is.
But which methods must be used to guarantee the
truth of theory?
4
18C Views on the Methodology Which Guarantees the
Truth of Ideas

• Empiricism
• Versus
• Rationalism

5
Empiricism
Rationalism

• All knowledge comes from foundational concepts
  known intuitively through reason, such as innate
  ideas.
• Other concepts are then deductively drawn from
  these.
• Rejects the idea that knowledge is based on both
  sense experience.

• All knowledge is grounded in experience
  (observation and experiment).
• Knowledge is developed by inductive argument.
• Rejects the theory of innate ideas

6
Failure of Rationalism

• Mathematics was an ideal-type for Rationalism,
  but problems such as Russells paradox and
  Goedels theorem showed that it was impossible to
  deduce all of mathematics from a few self-evident
  axioms.
• What were the innate ideas from which we could
  deduce our knowledge of the physical world?

7
Empiricism
Induction
8
The principle of Induction

• If a large number of A's (swans) have been
  observed under a variety of conditions and all
  A's have the property B (white), then by
  induction all A's have the property B. Valid
  general laws can be inferred from true
  observation statements.

9
(No Transcript)
10
Russells Inductivist Turkey
11
Inductivism a description of the principles of
science

• Accumulation Science grows by the accumulation
  of well-attested facts grounded in observation.
• Induction
• The principle of confirmation The more
  confirming instances there are the more plausible
  is the law.

12
Failure of Inductivism

• Induction cannot be justified by appeal to logic
  it goes beyond what is given and therefore is
  not guaranteed.
• Cannot be justified either on the basis of
  experience or by using a "principle of
  uniformity" as this leads to circular reasoning.
• Cannot be saved by a retreat from certainty to
  probability. There is no measure for the degree
  of inductive support that a given universal
  statement enjoys. (The paradox of the ravens, the
  problem of grue).

13

• We cannot prove that our scientific knowledge
  must be true as a result of the fact that we use
  a guaranteed method.
• Empiricists argue that nonetheless, science must
  be based on observation and experiment that is
  what enabled the great progress made in the
  scientific revolution.
• Positivism the idea that all knowledge must be
  based on directly observable, and therefore
  certain, quantities. All unobservable quantities
  (ego, mind, emotion) must be regarded as just
  short-hand for sets of observations.

14
Impact on psychology as an emerging discipline
15
Impact on Psychology
16
(No Transcript)
17

• Brentano (sophisticated Cartesian late 19c)
  psychology is the science of the soul (the
  mind-stuff), but it is an empirical science to be
  advanced by the study of the mental events in our
  own stream of consciousness by means of carefully
  controlled introspection under laboratory
  conditions. Cartesian laboratories were set up
  (e.g. William James at Harvard) and produced
  "some of the most tedious descriptive literature
  that had ever been written". Around the turn of
  the century the Cartesians dominated in
  psychology.
• However, introspection did not produce much and
  came to be seen as too subjective, as not
  scientific, not based on agreed data, whilst
  animal behaviour experimentalists (Pavlov and
  Watson for example) seemed to be producing
  interesting results.
• Perhaps the most striking example of the
  far-reaching influence of the inductivists is in
  the movement in psychology known as Behaviourism.
  The leading proponent of this school, B F
  Skinner, has had a major influence especially in
  educational psychology1.

18
(No Transcript)
19
(No Transcript)
20
Falsification Sir Karl Popper

• Theories can come from anywhere we dont and
  cant establish their truth by the method we use
  to develop them.
• No amount of evidence can verify that a theory is
  true.
• A single counter example can show that a theory
  is false.

21
Falsification

• All As are B
• This A is not B
• Therefore it is not true that All As are B
• The above is a logically valid argument.
• The general theory is falsified by a single
  counter observation.
• To be scientific a theory must be capable of
  falsification.

22
Problems with falsification

• Hypotheses or theories are never subjected to
  experimental test in isolation.
• Auxillary hypotheses are always necessarily
  (tacitly or explicitly) relied on.
• Any idea can be saved provided we adjust our
  auxillary hypotheses.
• Scientists do not reject theories when they do
  not agree with the observations or facts.
  (Fortunately).

23
Empiricism
Induction
Falsification is logically valid, but depends on
agreement about the facts or observations?
24
Observation

• There is more to seeing than meets the eyeball

Are these really separable consider visual
perception
Observations
Theory
Facts
25
Depends on prior knowledge
26
(No Transcript)
27
Depends on context
N R Hanson. (1958) Patterns of Discovery. CUP
28
(No Transcript)
29

• Is there a level of incorrigible observation?
• Up to know we have considered the basic
  observational level to be non-problematic, but is
  this idea sustainable? What is the fundamental
  level of certainty in our observations?
• Psychologism (Phenomenalism). The fundamental
  level is the sense data of a particular
  individual and physical objects are constructions
  from sense data.
• Physicalism An observation statement should not
  refer to sense-data but to physical objects1.
  The motivation behind physicalism is the belief
  that statements about physical objects are
  inter-subjective and that intersubjectivity is a
  necessary condition for science. Statements about
  private sense data are not capable of
  corroboration by others and so cannot form the
  basis for science. Statements about private sense
  data are incorrigible, but statements about
  physical objects are fallible.
• 1 Carnap (1995) argued that even in psychology
  observation statements should refer to physical
  objects and not subjects reports of their
  immediate subjective experiences.

30

• Fallibility of Observations
• The observed size of Venus does not vary
  throughout the year.
• In the Ptolemaic system (200AD) Venus was
  supposed to travel in a circular orbit around the
  stationary Earth (along with the Moon, the Sun
  and the other planets). It follows that the
  observed size of Venus should be constant.
• Copernican theory predicted that the observed
  size of Venus in the sky should vary throughout
  the year since in this system it orbits the sun.
  Even so, observations at the time of Copernicus
  of a non-varying size of Venus were generally
  accepted as true.
• However, the observation that Venus does not vary
  in size is now considered false, being based on
  the false assumption that the naked eye could
  judge the size of distance objects accurately.

31
Fallibility of Observations

• Observation statements are as fallible as the
  theories on which they depend and so cannot
  constitute a secure foundation for laws and
  theories.

32

• If observations are not objective, they cannot be
  the ultimate arbiter of theories.
• How can we rationally choose between rival
  theories? Is theory choice a rational process?
• Perhaps we need psychological/sociological
  explanations for science as well.

33
Summary

• The whole notion that there is an objective
  reality that can be revealed, as it is in itself,
  by the guaranteed scientific method does not seem
  tenable.
• There is no guaranteed scientific method.
• Theory choice is not a rational process.

34
Reading

• Yearley, S. (2005) Making Sense of Science.
  Chapter 1. Sage Publications. London.
• Chalmers, A. F.(1982). What is this thing called
  science? - - 2nd ed. Milton Keynes Open
  University Press.
• Harre, Rom. The rediscovery of the human mind
  http//www.massey.ac.nz/alock/virtual/korea.htm
  On line. Accessed 18/02/2003.
• Feyerabend P.K. (1975) Against Method. Chapters 6
  and 7. New Left Books.
• Popper, K.R. (1968) The Logic of Scientific
  Discovery. Chapter 5. Hutchinson.

35
On-Line

• The Internet Encyclopedia of Philosophywww.iep.ut
  m.edu/ accessed 17/02/05
• http//www.stephenjaygould.org/ctrl/popper_falsifi
  cation.html