Lecture 2 Is science rational and progressive? Realism and
instrumentalism Inference to the best explanation Criteria for
theory choice Logical positivists Thomas Kuhn and revolutions in
science Constructivism Examples: plate tectonics and
geomorphology
Slide 3
A 1950s education in Freud, Marx, and modernism is not a
sufficient qualification for a thinking person. Indeed, the
traditional intellectuals are, in a sense, increasingly
reactionary, and quite often proudly (and perversely) ignorant of
many of the truly significant intellectual accomplishments of our
time. Their culture, which dismisses science, is often non-
empirical. It uses its own jargon and washes its own laundry. It is
chiefly characterized by comment on comments, the swelling spiral
of commentary eventually reaching the point where the real world
gets lost. John Brockman (science publisher www.edge.org) A
scientific realist says...
Slide 4
Scientific Realism versus Instrumentalism Scientific realism
the aim of science is to provide true theories of the world All
theories are attempted descriptions of reality Instrumentalism
(anti-realism) the aim of science is to provide predictive theories
only Not global anti-realism i.e. poststructuralism (language trap)
Science provides true descriptions of the observable universe but
has no knowledge of unobservable universe Scientific theories are
instruments to predict observations
Slide 5
Do scientific theories represent reality? 1. How do we know
current theories are true if past theories were found to be false?
Quantity and quality of observational evidence 2. How do we know
which theories are true if multiple theories are consistent
withdata? Science requires additional criteria to make an inference
to the best explanation
Slide 6
Inference to the Best Explanation A type of non-deductive
inference On Christmas morning presents had been left by the tree
and the mince pies and sherry were gone! Late on Christmas Eve
footsteps were heard on the staircase Who delivered the presents
and ate the goodies? We learn to infer the best explanation based
on personal criteria and experience
Slide 7
What are the criteria for choosing explanations? Accuracy,
scope, consistency, fruitfulness, simplicity etc. E.g. Evolution by
natural selection explains similarities by descent from a common
ancestor replication & mutation & competition adaptation
Simplicity (parsimony) and explanatory power are evidence of its
truth How do you know that reality is simple and not complex?
natural selection intelligent design
Slide 8
The Logical Positivists (1920s to 1960s) Impressed by
objectivity of science and verification Context of discovery
historical, emotional, subjective Context of justification testing,
evidence, objective e.g. Kekule and the structure of benzene They
thought philosophy of science should address justification of
theory They were not interested in history
Slide 9
Thomas Kuhn (1922 - 1996) Is sociology of science important? An
historian of science who thought that ignoring history gives a nave
picture of the scientific enterprise Interested in scientific
revolutions when scientific ideas are replaced by radically new
ones e.g. Einsteinian revolution in physics, Darwinism in biology,
plate tectonics in geology Reference: Kuhn, T. S., 1962. The
Structure of Scientific Revolutions
Slide 10
Paradigms Shared assumptions, beliefs and values that unite the
community and allow normal science to take place Two components: A
set of fundamental theoretical assumptions accepted by the
scientific community A set of exemplars classic problems solved by
these theoretical assumptions
Slide 11
Normal Science A paradigm defines normal science for a period
sets the standards and specifies objectives for relevant research
coordinates research and initiates students into the tradition
Scientists work within a paradigm to solve minor puzzles When
anomalies are few they are ignored
Slide 12
Revolutionary Science As anomalies accumulate a crisis develops
Confidence in the old paradigm breaks down Fundamental scientific
ideas are up for grabs Paradigm shift a new paradigm is
established
Slide 13
Example 1: Tectonic shifts in paradigm? 19 th century: Static
Continents Observations: uplifted strata, geological folds and
faults E.g. James Dana Manual of Geology (1863) Explanations (no
unifying theory): undermining due to volcanic eruptions sudden
formation of volcanic vapours weight of accumulated formations
movement of the globes interior fluids temperature related
expansion and contraction
Slide 14
Earlier 20 th century growing unease Observations: matching
coastlines continuity of Permo- Carboniferous glacial sediments
similar fossils records Explanation: continental drift (Alfred
Wegener, 1912) Not generally supported due to lack of evidence for
a suitable mechanism
Slide 15
Later 20 th century: Plate Tectonicsa paradigm shift?
Observations: earthquake zones & deep earthquakes beneath ocean
trenches variable magnetic field direction in rocks of different
ages (1956) magnetic striping at ocean ridges suggests seafloor
spreading (1961) Explanations: constructive margins, subduction
zones etc Unifying theory for geology & geomorphology of the
Earth
Slide 16
Can paradigms be compared? Kuhn - alternative paradigms so
different they cannot be compared - no common language for
translation e.g. Newtonian and Einsteinian physicists (supposedly)
have a different concept of mass and in discussion they talk past
each other Criticism of incommensurability: If it is agreed that
theories are incompatible then they must be comparable and cannot
be incommensurable Kuhn: Newtons and Einsteins theories are
incompatible
Slide 17
Are data independent and objective? Cannot isolate
theory-neutral data because: Perception is conditioned by
background beliefs Reporting of data is couched in theoretical
language Criticisms of theory-ladenness of data: Data may be
adequately free of theoretical contamination to be acceptable to
proponents of alternative paradigms e.g. Believers in geocentric
and heliocentric paradigms could still agree on statements like on
14 th May the Sun rose at 5:30 am
Slide 18
Some criticisms of Kuhns ideas... Between Kuhns normal science
and extraordinary science there are many gradations (Popper, 1970)
If an experiment does not hold out the possibility of causing one
to revise ones views, it is hard to see why it should be done at
all (Medawar, 1979)
Slide 19
Example 2: Changing paradigms in geomorphology? Catastrophism
uniformitarianism Shift (Orme, 2002 Geomorphology 47)
Kuhns controversies: Is science rational? Adopting a new
paradigm involves a degree of faith and is not purely based on
objective evidence The transfer of allegiance from one paradigm to
another is a conversion experience Peer pressure plays a large role
in paradigm acceptance Is science progressive? Facts about the
world are paradigm-relative Scientific knowledge is not necessarily
cumulative Does the concept of objective truth even make
sense?
Slide 22
Kuhns clarifications Science may be viewed as rational
Incommensurabilty between paradigms is partial Paradigm choice is
made by reasonable shared criteria: accuracy, scope, consistency,
simplicity, fruitfulness etc. Paradigm choice based on reasonable
shared criteria is rational Science may be viewed as progressive
Conceived as a set of instruments for solving technical puzzles in
selected areas, science clearly gains in precision and scope with
the passage of time. As an instrument, science undoubtedly
progresses
Slide 23
So...can the scientific method be rigorously defined? Many have
attempted to define the criteria for a good theory Simplicity
(parsimony), breadth, goodness of fit etc. No rigorous algorithm
(sequence of instructions) Kuhn claimed there is no algorithm for
theory choice Science appears to conform to a looser definition and
more relaxed concept of rationality than often assumed
Slide 24
Summary Realism and instrumentalism Inference to the best
explanation Logical positivists emphasis on theory Thomas Kuhns
emphasis on history Paradigms, normal and revolutionary science
Science is more loosely defined than often assumed Science is
rational when viewed against shared criteria As an instrument, it
progressively solves empirical questions Final thought: What are
appropriate and inappropriate applications of science in
geography?