Popper:

1
Popper Falsifiability is the criterionLecture
updated!

• 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.
• Falsifiability is a criterion scientists often
  site as do their critics!

2
Popper Falsifiability is the criterion

• Falsifiability
• Do be scientific, a claim, hypothesis, or theory
  must be, in principle at least?, falsifiable
• It must rule out/prohibit some observable (in
  principle?) object or event that, if observed,
  would demonstrate the claim, hypothesis or theory
  is false.
• If a claim or theory is compatible with all and
  any states of affairs, it is not falsifiable and
  thus not scientific (or, as Popper claims it is
  pseudo-scientific

3
Popper Falsifiability is the criterion

• Exhibit A
• In court cases decided (in one instance) by the
  US Supreme Court and by state supreme courts,
  first Creation Science and, more recently,
  Intelligent Design were banned from public
  schools on the grounds that they were not
  falsifiable, thus not scientific but rather
  religion (which cant be taught in public
  schools).
• Advocates of CS and ID then argued that
  evolutionary theory isnt falsifiable and, thus,
  not science!
• BTW is String Theory falsifiable?

4
Popper Falsifiability is the criterion

• His targets
• Adlerian psychology
• Freudian psychology
• Marxist theory
• What they have in common
• Their advocates see confirmations everywhere
• Where (I contend) they differ
• The first two may well be unfalsifiable
• The problem with Marxism (which was falsifiable)
  was with its advocates, not the theory itself

5
Popper Falsifiability is the criterion

• His targets
• Adlerian psychology
• Freudian psychology
• What renders them unfalsifiable?
• Not the uncritical attitude of their advocates
• The second has a protective belt that
  effectively repels all counter-evidence
• The first is simply compatible with any way an
  agent behaves!

6
Popper Falsifiability is the criterion

• 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, by just one observation.

7
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.

8
The Minds Big Bang

• The Paleolithic period (or Old Stone Age) is the
  earliest period of human development. Dating from
  about 2 million years ago, and ending in various
  places between 50,000 and 10,000 years ago, it is
  roughly co-extensive with the geologic period
  known as the Pleistocene some would update
  timeline
• An epoch which was marked by continuous cooling,
  which resulted in several ice ages. During the
  period, hominids become increasingly advanced in
  terms of fire and tool making, and modern humans
  emerge.

9
The Minds Big Bang

• Evidence of Cro-Magnon humans (one of several
  varieties of modern humans that lived during the
  period) indicates they lived some 50,000-10,000
  years ago. Anatomically the same as todays Homo
  sapiens and fossil remains, graves, artifacts,
  and dwellings have been found throughout Europe.
• It is believed that their arrival in Europe, when
  they encountered another hominid species, the
  Neanderthals, resulted in the extinction of the
  latter.
• In a recent article in The Science Times, it
  was hypothesized that Cro-Magnons were so
  startled to be confronted with another bi-pedal,
  tool using (and much larger!) hominid, that they
  developed the practice of designing beads that
  would identify them.

10
The Minds Big Bang

• The discovery of decorative beads
• Differences in the treatment that humans and
  Neanderthals provided the dead
• Cave paintings
• Fossil evidence (particularly skulls) of
  differences between Neanderthals and humans
• Relatively quick innovations (in, for example,
  spears and spear heads)
• Migrations of early humans across Europe
• Cave instruments and music
• Biological changes in the brain
• Comparison of humans and chimpanzees
• The emergence and significance of language
• Cultural forces overriding biological forces

11
Popper Falsifiability is the criterion

• Although it was unclear at the time whether
  Einsteins theory was true, it turns out to be
  scientific on Poppers view.
• 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

12
Eddingtons experiment

• A reconstruction of what Eddingtons photographs
  demonstrated

13
Eddingtons experiment

• Again, it was not the confirmation of Relativity
  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.
• Moreover, confirmations of a theory should only
  count as significant when the theory in question
  is bold

14
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)

15
Things we will later consider

• The difference between a theory actually being
  un-falsifiable, 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)