1
The Demarcation Problem(Science and
pseudo-science)

• Case one Geocentrism (an earth-centered
  universe) vs. Heliocentrism (a sun centered
  universe).

2
The Demarcation Problem(Science and
pseudo-science)

• Case one Geocentrism (an earth-centered
  universe) vs. Heliocentrism (a sun centered
  universe).

3
The Demarcation Problem

• Case one Geocentrism (an earth-centered
  universe) vs. Heliocentrism (a sun centered
  universe).
• Was geocentrism a scientific hypothesis?
• How much of it was based on theology or appeals
  to ancient authorities (such as Aristotle),
  rather than on empirical evidence and/or
  scientific reasoning?
• Was heliocentrism a scientific hypothesis?
• How could it be if it so obviously clashed with
  our experience?
• Where is the wind? Why dont we feel the earths
  motion?
• How does a telescope work? How do we know what
  Galileo claimed to see (e.g., that Jupiter has
  moons) werent just artifacts produced by his
  telescope?

4
Popper Falsifiability is the criterion

• Why reject verifiability?
• By then (for reasons we will study shortly),
  scientists and philosophers recognized that no
  empirical theory could ever be proven.
• This seemed to take any degree of certainty off
  the table
• Moreover, according to Popper, verifications or
  confirmations of a theory were, in many cases,
  all too easy to come by.

5
Popper Falsifiability is the criterion

• By then (for reasons we will study shortly),
  scientists and philosophers recognized that no
  empirical theory could ever be proven.
• But Popper has logic on his side for while no
  empirical theory can be proven, any (genuinely)
  empirical theory can be disproven and, at least
  in principle, by just one failed experiment or
  prediction.

6
The logic of confirmation vs. the logic of
falsification

• If H, then I
• I
• ------------------
• H
• Logic of confirmation
• Affirming the consequent
• Deductively invalid

• If H, then I
• Not I
• ------------------
• Not H
• Logic of falsification
• Modus Tollens
• Deductively valid.

7
Popper Falsifiability is the criterion

• In 1919, Popper compares 4 then popular and much
  discussed theories Relativity, Marxism,
  Freudianism, and Adlerian Psychology
• Although the last three might contain important
  truths or insights, and although they are said to
  enjoy extensive confirmations (supporting
  observations and experiments), they turn out
  not to be scientific, according the Popper.
• Although it was unclear at the time whether
  Einsteins theory was true, it turns out to be
  scientific on Poppers view.

8
Eddingtons experiment

• Einsteins theories predicted that light, like
  material objects, is subject to the gravitational
  pull of large objects
• Hypothesis light traveling from a star that is
  located behind the sun from the perspective of
  the Earth should bend as it passes the sun
• A bold hypothesis and one that would take years
  to carry out. Scientists had to wait for a solar
  eclipse so that a stars light would be visible

9
Eddingtons experiment

• A reconstruction of what Eddingtons photographs
  demonstrated

10
Eddingtons experiment

• A bold hypothesis and one that would take years
  to carry out. Scientists had to wait for a solar
  eclipse so that a stars light would be visible
• But it was not its confirmation that struck
  Popper, but its falsifiability and boldness even
  before Eddingtons experiment confirmed it,
  scientists knew what would, in principle, falsify
  the hypothesis namely, not observing the bending
  of the light traveling from the star toward Earth.

11
Falsifiability

• The criterion used to make these judgments and to
  be generalized
• Every genuinely scientific theory is a
  prohibition. It forbids certain things to happen.
• A theory that is not falsifiable (refutable) by
  any conceivable event is not scientific.
• Confirmations should only count as supporting a
  theory if, like that of Relativity, they involve
  risky and bold predictions.

12
Falsifiability

• Using the criterion to judge Marxism,
  Freudianism, and Adlerian Psychology as examples
  of pseudo-science
• The problems with Freudian and Adlerian
  psycyhology
• Each is compatible with every possible state of
  affairs.
• Each contains within it the means to explain
  conflicting results (e.g., whether an adult jumps
  into water to save a drowning child or does not
  jump in explanation his or her feelings of
  inadequacy)
• The unconscious of Freudian theory undercuts
  any individuals claim not to experience what
  Freud predicts every male, or every female,
  experiences.

13
Falsifiability

• Marxism is rendered pseudo-scientific not because
  the original theory was not falsifiable.
• Marx and Engels claims about upcoming
  proletariat revolutions in capitalist societies
  were falsifiable, and in most cases, falsified.
• But advocates of Marxism, in efforts to save the
  theory from the falsifications, introduce Ad hoc
  hypotheses to save it.
• Ad hoc From the Latin for this purpose (in
  this case, saving the theory)

14
Falsifiability

• Ad hoc hypotheses and Marxism
• According to Marxism, each society has an
  ideology a guiding set of ideas that
  informs its political and economic theories and
  institutions
• Ideologies function to make the present political
  and economic status quo look natural
• So, workers (members of the proletariat) dont
  recognize that capitalism exploits them and have
  to be taught to see through the ideology that
  their economic system is a meritocracy with
  unlimited possibilities to succeed.

15
Falsifiability

• When the many revolutions Marx and Engels
  predicted did not occur, later advocates of the
  theory pointed to the capitalist ideology as the
  culprit workers couldnt see through it and
  recognize the truth. Hence, few revolutions.
• Note that this is a different kind of case from
  Freudian and Adlerian psychology its not the
  theory that is unfalsifiable, its the attitude
  of its advocates and their willingness to propose
  Ad hoc hypotheses to save it from falsification

16
Things we will later consider

• The difference between a theory actually being
  unfalsifiable, by its nature or structure, and a
  theorys advocates resorting to ad hoc hypotheses
  to save it.
• Isnt it possible that a genuinely scientific
  theory will be confirmed repeatedly and no
  counter-examples encountered?
• The in principle caveat is important. There is
  a little red school house on the dark side of
  Jupiter is silly but falsifiable in principle.
• How easy or straightforward is it to identify
  added hypotheses that ARE ad hoc, but added
  hypotheses that are NOT ad hoc (i.e., are
  defensible)

17
The Elegant Universe preview

• The two pillars of contemporary physics
  Relativity and Quantum mechanics are (it
  appears) incompatible.
• Relativity theory concerns very large objects
  (galaxies, starts, and the like)
• Quantum mechanics concerns very small objects
  (atoms and subatomic particles)
• They yield different laws.
• Unification a theory of everything is for
  many physicists the Holy Grail.

18
The Elegant Universe preview

• String Theory is seen by some physicists as
  precisely the theory that will unite Relativity
  and Quantum mechanics it is (it will turn out
  to be) the theory of everything.
• It posits that everything, including Ledermans
  quarks and leptons, is made of tiny, vibrating
  strands of energy (theyre called strings)
• It has led to some strange predictions parallel
  universes and 11 (yes, 11!) dimensions, among
  other things.

19
The Elegant Universe preview

• Note how string theory, like particle physics,
  quantum theory, the Greeks of Miletus, and
  Democritus, assumes there is one stuff out of
  which everything is made.
• Strings are, by their nature, unobservable (and,
  indeed, there are no technologies able to
  indirectly observe their effects although some
  hope LHC will help here)
• Note the primary reasons physicists who are not
  String Theorists reject its status as
  scientific!

20
The Elegant Universe preview

• Some of the players
• Brian Greene, narrator and author of the book of
  the same title. Professor of physics at Columbia
  University. An advocate of String Theory
• Sheldon Glashow, Professor of Physics, Harvard,
  Noble Prize in Physics, author of the Credo we
  read earlier.
• Steven Weinberg, Professor of Physics, University
  of Texas, Austin. Shared the Noble Prize with
  Glashow for their construction of The Standard
  Model in physics.