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The semantics of the Newtonian and relativity
theories that Feyerabend says are incommensurable
may be examined by considering their synthetic
statements analytically.
By way of example consider one of the more
famous empirical tests of Einstein's general theory
of relativity, the 1919-eclipse test that had such a
formative influence on Popper.
Two British astronomers undertook this test,
Sir Arthur Eddington of Cambridge University and Sir
Frank Doyle of the Royal Greenwich Observatory.
The test consisted of measuring the
gravitationally produced bending of starlight
visible during an eclipse of the sun that occurred
on May 29, 1919, and then comparing measurements of
the visible stars' positions with the different
predictions made by Einstein's general theory of
relativity and by Newton's celestial mechanics.
The test design included the use of
telescopes and photographic equipment for recording
the telescopic images of the stars.
Firstly reference photographs were made
during ordinary night darkness of the stars that
would be visible in the proximity of the eclipsed
sun.
These photographs were used for comparison
with photographs of the same stars made during the
eclipse.
They were made with the telescope at Oxford
University several months prior to the eclipse, when
these stars would be visible at night in England.
Then the astronomers journeyed to the island
of Principe off the coast of West Africa, in order
to be in the path of the total solar eclipse.
During the darkness produced by the eclipse
they photographed the stars that were visible in the
proximity of the sun's disk.
They then had two sets of photographs: An
earlier set displayed images of the stars unaffected
by the gravitational effects of the sun.
A later set displayed images of the stars
near the edge of the disk of the eclipsed sun and
therefore produced by light rays affected by the
sun's gravitational influence.
The stars in both sets of photographs that
are farthest from the sun in the eclipse photographs
are deflected only negligibly in the eclipse
photograph.
And since different telescopes were used for
making the two sets of photographs, reference to
these effectively undeflected star images was used
to determine an overall magnification correction.
But correction furthermore had to be made for
distorting refraction due to atmospheric turbulence
and heat gradients.
The distortions are large enough to be
comparable to the effect being measured.
But they are also random from photograph to
photograph, and the correction were made by
averaging over the many photographs.
Such are the essentials of the design of the
Eddington eclipse experiment.
The amount of deflection calculated with the
general theory of relativity is 1.75 arc seconds.
Eddington's findings showed a deflection of
1.60 + 0.31 arc seconds.
The error in these measurements is small
enough to conclude that Einstein's general theory is
valid, and that the Newtonian celestial mechanics
can no longer be considered valid.
Later experiments have reduced the error of
measurement, thereby further validating the
relativity hypothesis.
In this experiment the test design statements
include description of the optical and photographic
equipment and of their functioning, of the
conditions in which they were used, and of the
photographs of the measured phenomenon made with
these measurement instruments.
These statements are universal, since they
describe the repeatable experiment, and are presumed
to be true characterizations of the experimental set
up.
The theory statements are also universal, and
each theory shares descriptive variables with the
same set of test design statements.
If the test design statements are viewed as
analytic statements, then any descriptive variable
occurring both in a test design statement and in
either theory has a univocal semantics with part of
its meaning contributed by one or several test
design statements. This semantics is shared by both
theories, and it makes the theories semantically
commensurable.
Feyerabend maintained that theories are
incommensurable, because there is no concept that is
general enough to include both the Euclidian concept
of space occurring in Newton's theory and the
Reimannian concept occurring in Einstein's theory.
In fact the common part of the meanings in
the semantics of the descriptive terms common to the
two theories and to the test design statements, are
not common meanings due to a more general
geometrical concept.
There is a common meaning because the test
design statements are silent about the claims made
by either theory, even as both the theories claim to
reference the same instances that the test design
statements definitively describe.
Before the test this silence constitutes the
vagueness in the common part of the meaning of the
terms shared by the theory statements and defined by
the test design statements.
In the case of the test design for
Eddington's eclipse experiment, it may be said that
before the test the meanings contributed by the test
design statements are not properly called either
Newtonian or Einsteinian.
For purposes of describing the experimental
set up, their semantics have the status as
Heisenberg's "everyday” concepts that are
silent about the relation between parallel lines at
distances much greater than those in the apparatus.
After the test is executed, the
nonfalsification of the relativistic theory and the
falsification of the Newtonian theory are known
outcomes of the test.
This acceptance of the relativity theory is a
pragmatic transformation giving it the semantically
defining status of an analytic statement, and the
statements of the theory supply part of the
semantics for each descriptive term common to the
theory and the test design statements.
This semantical contribution by the
nonfalsified theory to each of these common
descriptive variables may be said to resolve some of
the vagueness in the whole meaning complex
associated with each of these common terms, and thus
the terms may be said to have Einsteinian semantics.
But the semantics supplied to these terms by
their test design statements is still vague, just as
before the test.
However, if the test design statements are
subsequently derived logically from the relativistic
theory, then these common terms receive still more
Einsteinian semantic values and additional structure
from the accepted relativity theory.
In this case everyday concepts may still
describe the phenomenon, but the Einsteinian
concepts are resolutions of the vagueness in the
everyday concepts in the descriptive terms in the
test design statements.
In either case, regardless of whether or not
the test design statements describing the
experimental set up can be logically derived from
the relativity theory, no resolution of the everyday
concepts to Newtonian concepts is involved either
before, during, or after the test, except for the
convinced advocates of the Newtonian theory before
the latter theory's falsification.
After the test outcome falsifying the
Newtonian theory, even the most convinced advocates
of the Newtonian theory must accept the semantically
controlling role of the test design statements, or
reconsider and reject the test design itself.
Nonetheless some physicists inaccurately
refer to the concepts in the test design statements
of relativity theory as Newtonian concepts.
This is because any relativistic effects in
the test equipment are too small to be detected or
measured, and therefore do not jeopardize the
conclusiveness of the test.
For example two different telescopes were
used in the Eddington eclipse experiment to produce
the photographs, one used before the eclipse and
another used during the eclipse.
Since the resulting two sets of photographs
were compared, a correction had to be made for differences
in magnification.
But no correction was even considered for
the different deflections of starlight inside the
telescopes due to the different gravitational
effects of their different masses even by those who
believed in the relativity theory, because such
differential relativistic effects are not
empirically detectable.
But the nonmeasurability or undetectability
does not imply that the test design statements
affirm the Newtonian theory.
For the test to have any contingency the test
design statements must be silent about the tested
theory and any alternative to it.
Consequently the concepts in the test design
statements describing the phenomena were vague about
any relativistic effect introduced by the different
masses of the two telescopes, and the concepts in
the test design statements are too vague to be
described as Newtonian or Einsteinian.
This vagueness in the concepts in test design
statements is indicated by a possible variation
retrospectively called a measurement error that is
not due to failure to execute the test in conformity
with the test design, and that is recognized only
after the test outcome is accepted.
There was such error in the Eddington
experiment, but it was very small relative to the
measured deflection of starlight by the sun's
gravitational force through interstellar distances.
This inaccuracy due to vagueness is relative
to the other concepts in the test design statements,
and it must be distinguished from the vagueness
relative to the concepts in the theory.
Before the test the meaning parts or semantic
values defined by the test design statements are
vague with respect to those defined by the theory
statements, but this vagueness does not affect the
measurement accuracy, since the condition of
independence precludes the theory statements being
used for measurement.
In addition to Bohr's complementarity thesis
and his own incommensurability thesis, Feyerabend is
led to his radical historicism by the view that
whether in philosophy of science or in any social
science, cultural views and values including the
criteria and research practices of empirical science
are inseparable from historical conditions.
In its radical variant it says that
particular historical circumstances do not function
to supply initial conditions for universal theories
describing recurrent aspects of human social
behavior, but rather preclude the validity of
universals altogether.
The persuasive objection to this historicism
is that concepts are inherently universal (or as
Popper says, all terms are disposition terms).
The metatheory, which proposes using
synthetic universal statements analytically for
semantical description, which also enables
exhibiting semantical continuity through scientific
change through history, is a variation on this old
but valid objection to this old philosophy of
historicism.
However, Feyerabend's historicism enjoys a
novel plausibility that could not be admitted by
philosophies from Platonism to Positivism, which
advance a naturalistic philosophy of the semantics
of terms.
Platonic Ideas, Aristotelian forms and simple
apprehensions, Romantic intuitions, and Positivistic
phenomena, sensations, sense data, and
operationalist definitions are all variations on the
myth of the given.
The scientific revolutions of the twentieth
century have forced philosophers, and specifically
Pragmatists, to affirm that meaning and belief are
mutually conditioning, and in this sense are
relativized to one another.
But universal statements used to describe the
real world condition this relativism.
The real world is what imposes constraints on
this mutual conditioning in language that makes
falsification possible, and that reveals the real
world to us.
Given any selected set of concepts, only some
statements can be maintained; and conversely given
any selected set of stated beliefs, only some
concepts may be defined.
The selection of truths is negotiable among
interested scientists.
But outside the narrow limits of measurement
error and associated conceptual vagueness, truth
conditioning expressed in universal statements
linking initial conditions and test outcomes is not
negotiable once test design statements are chosen.
New experiences anomalous to our universal
beliefs force revisions of those universal beliefs
and therefore of their semantics.
In empirical science the locus of the
semantical revision is a proposed universal
hypothesis conditioned upon chosen universal test
design statements.
The empirical test is the window to new
vision.
The evolution of thinking from Conant's
recognition of prejudice in science to Feyerabend's
counterinduction thesis has brought to light an
important limitation in Popper's falsificationist
thesis of scientific criticism.
In this respect Feyerabend's philosophy of
science represents a development beyond Popper, even
after discounting Feyerabend's radical relativism.
Popper had rejected the Positivists'
naturalistic philosophy of the semantics of
language, and maintained that every statement in
science can be revised.
But the paradigmatic status he accorded to
Eddington's 1919 eclipse experiment as a crucial
experiment had deflected Popper from exploring the
implications of the artifactual semantics thesis,
because he identified all semantical analysis with
essentialism.
He saw that the decidability of a crucial
experiment depends on the scientist sticking to his
problem, which is to say that the scientist should
not redefine his problem by reconsidering any
experiment's test design, especially after the test
outcome has been a falsification of the proposed
theory.
Such reconsiderations in Popper's view have
no contributing function in the development of
science; they are objectionable because they are ad
hoc content-decreasing stratagems, merely
evasions.
But the prejudiced or tenacious response of a
scientist to an apparently falsifying test outcome
does have a contributing function in the development
of science, as Feyerabend illustrates in his
examination of Galileo's arguments for the
Copernican cosmology.
Use of the apparently falsified theory as a
detecting device by letting his prejudicial belief
in the heliocentric theory control the semantics of
observational description, enabled Galileo to
reinterpret observations previously described with
the equally prejudiced alternative semantics built
into the Aristotelian cosmology.
This was also the strategy used by Heisenberg,
when he reinterpreted the observational description
of the electron in the Wilson cloud chamber
experiment with the semantics of his indeterminacy
relations pursuant to Einstein's anticipation of
Feyerabend's Thesis I, i.e. that theory decides what
the scientist can observe.
As it happens, the cloud chamber experiment
was not designed to decide between Newtonian and
quantum mechanics.
The water droplets suggesting discontinuity
in the tracks are very large in comparison to the
electron, and the produced effect admits easily to
either interpretation.
The counterinduction strategy could also have
been used by tenacious Newtonians who chose to
reject the findings from Eddington's eclipse
experiment.
The artifactual status of the semantics of
language permits the dissenting scientists to view
the falsifying test outcome as a refutation of one
or several test design statements rather than as a
refutation of the Newtonian theory, although such a
dissenting Newtonian would likely be expected by his
colleagues to offer an alternative test design.
In any event what some scientists view as
definitive test design statements, others may decide
to view as falsified theory.
Feyerabend recognizes that there are
semantical consequences to counterinduction.
In "Trivializing Knowledge" he
states that the contents of theories and experiments
are constituted by the refutation performed and
accepted by the scientific community, rather than
being the basis on which falsifiability can be
decided and refutation can be carried out as Popper
maintains.
He considers the stock theory "All
ravens are black", and states that while a
white raven falsifies the theory, the refutation
depends on the reasons for the anomalous raven's
whiteness.
Earlier in his "Popper's Objective
Knowledge" he gives the same example, and says
that the decision about the significance of the
anomalously white raven depends on having a theory
of color production in animals.
But his discussion by means of this stock
theory pertains more to the factors that motivate a
scientific community to decide between test design
and theory statements, than to a description of the
semantics resulting from that decision.
Feyerabend has no metatheory of semantical
description for characterizing the contents of
theories and experiments.
In this respect Feyerabend's philosophy
suffers the same deficiency as Popper's.
The conflicts between Popper and Feyerabend
were struggles between giants in the philosophy of
science profession.
Having started in the theatre before turning
to philosophy, Feyerabend chose a theatrical writing
style that offends the droll scholars of the
profession, who tend to treat him dismissively.
But every profession has its pedantic slow
learners.
Feyerabend stands above the academic crowd by
an order of magnitude. He was an outstanding
twentieth century philosopher of science, who
advanced the frontier of the discipline, as it was
turning from an encrusted Positivism to the
contemporary Pragmatism.
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