Science news
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“Becoming Human,” 3 part series by NOVA, began last
Tuesday night and continues for 2 more weeks on
Tuesdays.
One hypothesis considered as an explanation of
evolution of human mental capacities/brain size: climate
change.
Earlier hypothesis emphasized bidpedalism, but that was
before we found fossils of other hominids with relatively
small brains.
Prediction? NY Times review: If we go through another
period of increasingly hot and dry climate, our
descendants might be much smarter … and have heads
the size of basketballs 
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Science news
Signs of early Homo sapiens in China?
Fossils over 100,000 years old found in southern
China
Taken by Chinese scientists to challenge the
hypothesis that the species originated in Africa
and spread from there
Critics: Far too little evidence
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A fragment of a lower jaw bone and some teeth
Challenges to Falsificationism
Complicating the logic of falsification
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‘If H, then I’ is really ‘If [H & (A1… An)], then I’
More from Hempel:
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‘I’ in ‘If H, then I’
is itself shorthand for ‘If C, then E’
where ‘C’ symbolizes some condition, and ‘E’ some
event or phenomenon.
And ‘if C, then E’
is understood as “if some condition is brought about,
then we will observe E .”
If this is correct, then the actual logic of falsification, on
Hempel’s model, is
Challenges to Falsificationism
If [H & (A1… & An)], then (if C then E)
Not E
---------------------------------------------Either not H & (A1… & An) or not C
On the left side, H may be incorrect – but it could be
correct and one or more of the auxiliary assumptions is
the problem (Brahe).
Or (as indicated by the right side), it may be that the
conditions weren’t brought about (med students didn’t
wash their hands...)
Holism as yet another challenge to
Falsificationism
Duhem/Quine thesis: It is bodies of theory (or
systems of theories), not individual hypotheses,
that entail predictions.
 If T (for some body of theory), then (if H, then I)
 Not I
 --------------------------------------------Not some one or more statements of T or not H
Pierre Duhem: a bench physicist writing in the 1930s
W.V. Quine: philosopher of science writing from the
mid twentieth century to its end
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Holism
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If T, then (if H, then I)
not I
-----------------------------Not some part of T or not H
Given what actually follows logically and empirically
from ‘not I’, one needs to decide that ‘not H’ follows,
rather than some part or whole of T; i.e., one has to
choose to hold T firm and H infirm.
Are the choices arbitrary? Made on the basis of selfinterest?
What are the consequences for objectivity?
Holism
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Duhem’s examples (you do not need to
memorize the details… just what he uses them to
illustrate):
 Neumann
assumed a hypothesis that, if correct, was
taken to predict that in an experiment involving a
light beam reflected at a particular degree of angle,
there ought to appear alternatively dark and light
interference bands
 Weiner, who challenged Neumann’s hypothesis,
performed a test in which the predicted interference
bands did not appear.
 Had he, in fact, falsified, Neumann’s hypothesis?
Holism
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Duhem’s examples:
 No,
according to Duhem, because Weiner had not
only used Neumann’s hypothesis to get the prediction
and design the experiment: instead he brought and
joined a lot of hypotheses to do both.
 So what he actually demonstrated was that either
Neumann’s hypothesis is incorrect, or one or more of
the assumptions Weiner himself made, was/were
incorrect.
Holism
In the case concerning whether light would travel faster in
water than in air or vice versa as a test of Newton’s
hypothesis that light consists of tiny projectiles vs. that
light consists of waves moving through a medium:
 It was the whole system Newton proposed that was
under test, not the hypothesis that light is made up of
projectiles
 So, the moral is the same:
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Nothing, logically or experimentally, stops us from accepting
the hypothesis allegedly falsified and shifting the weight of the
experimental contradiction to some other hypothesis or part
of the larger theory that the experimenter assumes.
Both experiments Duhem cites had been taken as
among the most decisive ones in optics; he is
challenging this.
Holism
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The model of Falsificationism as how scientists do or should
reason, reflects “unfamiliarity with physics’ actual
functioning”
Such people assume that “each one of the hypotheses
employed in physics can be taken in isolation, checked by
experiment, and then when many varied tests have
established its validity, given a definitive place in the system
of physics.”
“In reality, this is not the case. Physics is not a machine
which lets itself be taken apart… physical science is a system
that must be taken as a whole… If something goes wrong, if
some discomfort is felt it, the physicist will have to ferret out
… which “organ” needs to be remedied or modified without
the possibility of isolating this organ and examining it apart.”
Holism
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So-called crucial experiments:
Assume the logic of Reductio ad absurdum, an
argument form that works in mathematics
But not, Duhem argues, in empirical science
Either P or Q
1. Either H1 or H2
Not P
2. Not H2
----------------------------------Q
H1
Recall Paley’s reasoning…
Holism
 Reductio
ad absurdum only works if one can list
all the hypotheses that can account for some
phenomena and then by experimental
contradiction, eliminate all except one.
 If you could do this, the resulting hypothesis
would look like a certainty.
 But you cannot. One can never be sure one has
identified every possible hypothesis that might
account for the phenomena.
Holism
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An example: In the late 1980’s, researchers developed a
drug predicted to be capable of thwarting the
replication of the HIV virus implicated in AIDS.
H: “All things being equal … the drug will be effective”
In experiments, one group was given the drug and the
other a placebo.
The initial trials (running over 2 years) confirmed the
drug’s predicted success. But in the 3rd year, it stopped
being effective.
Initial results (showing effectiveness) were taken to be
mistaken
And the hypothesis was rejected by some
Holism
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Then current theories suggested that it didn’t matter if
the drug was stored and delivered in glass or plastic
containers.
After the initial 2 year period, the drug was stored and
delivered in plastic rather than glass containers.
Thus the conclusion that not H presumed the truth of
this background knowledge – and it was wrong.
Storing the drug in plastic containers did affect it.
Holism
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Critics of the Quine/Duhem (or Duhem/Quine) thesis
argued that if correct, theories could never be refuted
by evidence – but only by decisions made by scientists
in the relevant field
This, they argued, leads to relativism and/or degrees of
subjectivity that challenge scientific objectivity
Duhem and Quine: not so. It just means that science
isn’t a machine.
Duhem: the physicist is more like a doctor making a
diagnosis with available information, than a watchmaker
who fixes a watch.
Holism
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Later in the full chapter, Duhem argues that there are
values (epistemic or cognitive) that guide the scientist’s
choice
A list many cite includes:
Simplicity
Conservatism
Explanatory power
Empirical adequacy and/or success
Fruitfulness
Part 2
Introducing Kuhn
Kuhn’s The Structure of Scientific Revolutions (SSR)
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First published in 1962, Kuhn’s SSR was named one of the 50th
most important books of the 21st century by many lists
(including The New York Times)
Kuhn: a bench physicist who became interested in the history
of science (actual history) and argued that it did not match the
reconstructions philosophers and historians of science, and
scientists themselves, offered
While historians and philosophers of science (as well as
scientists) emphasized revolutions in science as models of how
science works, Kuhn emphasized what he called “Normal
Science” – the kind of science most scientists engage in all of
their lives that does not look what philosophers or historians
of science, or even working scientists, hold up as “scientific
method”
Kuhn’s SSR
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From “pre-science” to “normal science” to “crisis” to “revolution
Pre-science
Lots of “schools” arguing over fundamentals
No agreement over what is the most important phenomena to
be explained
No agreement on a basic theory or how the most basic
phenomena are to be explained
The emergence of a “paradigm”
The beginning of a “normal science” (as opposed to a prescience”) tradition
The emergence of a “paradigm” which
Solves a lot of puzzles (or promises to solve
puzzles) that need to be solved
Kuhn’s SSR
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Is like a “judicial decision” in that it invites further articulation
Brown v. Board of Education
 “Separate
but equal” is internally inconsistent
 Originally about racially-segregated schools
 But articulated to apply to other apparently “separate
but equal” laws and practices
 Gender
 Sexuality
 And other laws that cite “separate but equal”
standards”
Kuhn’s SSR
Once a science community accepts a paradigm
(Copernican astronomy, Newtonian physics,
Darwinian natural selection, Relativity, Quantum
physics…) the paradigm itself is unquestioned and
work begins on
 Puzzle solving: the paradigm indicates what
problems are important (nature of the orbits of
the planets, how natural selection works….) and
this results in a
 Puzzle-solving tradition
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Kuhn’s SSR
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Normal science (everyday, most of the time science)
involves puzzle solving
Assume that any puzzle suggested by a paradigm is
intrinsically important and
 Has a solution that the paradigm, itself, supplies
 Can be solved with sufficient ingenuity and/or
creativity
 Any failure to solve the puzzle is due to the
researcher (her or his understanding of the puzzle,
appropriate tests… but not the paradigm.
Kuhn’s SSR
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Normal science (everyday, most of the time, science) is a
closed-minded enterprise
Is not looking for anomalies
Seeks only confirming evidence of the Paradigm and any
subsidiary hypotheses it suggests
Is an attempt to “fit nature into the boxes the Paradigm
supplies”
Will only pay attention to anomalies (counter-examples)
when
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It is no longer reasonable to blame the individual
researcher/test or
To wait for scientists of the next generation to find a solution or
there is a “competing paradigm”
Kuhn’s SSR
 Kuhn’s “diagnosis” of how Popper “went wrong”
 Not because (as Duhem article would suggest)
that Popper didn’t know the history of science
 But because he focused his attention on episodes
of revolution
 These, according to Kuhn, are rare and not
“typical” of how science proceeds