Underdetermination as an
Epistemological Test Tube:
Expounding Hidden Values
of the Scientific Community
Martin Carrier (Bielefeld University)
Underdetermination thesis: any given set of data can
always be represented by different, conceptually
Claim: underdetermination plays a fruitful role in
epistemology by pinpointing the impact of non-
empirical virtues or cognitive values on theory
=> Underdetermination contributes to illuminating
what scientific rationality actually is.
Duhem-Quine underdetermination brings to light the
non-empirical epistemic commitments which prevail
in the scientific community and which form an indis-
pensible part of our understanding of scientific
3. Duhem’s Master Argument for
Duhem: Confirmation and refutation of particular
hypotheses cannot be grounded on logic and
Hypothetico-deductive confirmation: The same
observational consequences may equally follow from
a different hypothesis incompatible with the first.
Example from geocentric astronomy: Eccenter
hypothesis and epicycle hypothesis as two empiri-
cally equivalent accounts of annual solar motion.
Hypothetico-deductive refutation: no hypothesis can
be refuted by relying on logic and experience only.
An anomalous observation merely demonstrates
that at least one of the assumptions brought to bear
in the test procedure is mistaken.
Principle of the uniformity of celestial motions.
Apparently non-uniform annual motion of the sun:
The two constructions saved the uniformity principle
at the expense of adjusting other assumptions.
Theories are creations of the human mind and never
lose their dependence on human imagination.
Nature always leaves room for alternative accounts.
Neither proofs nor refutations are part of scientific
4. Duhem, Quine, and Beyond: The
Career of Underdetermination
Duhemian characteristics of underdetermination:
• Reference to real-life theories, not to artificially
contrived toy models.
• The possibility of alternative accounts is stressed
but no recipe for actually constructing them is
• Underdetermination is confined to a given range
=> Duhem had temporary indistinguishability in
Temporary underdetermination plays an important
epistemological role: it serves to illuminate the
bearing of non-empirical virtues in judging hypoth-
eses and adopting theories.
Confirmational version: any given set of data can
always be represented by different, conceptually
Refutational variant: arbitrary hypotheses can be
maintained in the face of arbitrary evidence if one is
prepared to adjust the system of beliefs, maybe
profoundly, in other respects.
Discussion of underdetermination in the second half
of the 20th century: articulation of the thesis.
— Distinction between the observed and the unob-
served behavior of entities.
Rejected with reference to the goal of conceptual
— “Deoccamization”: supplanting a theoretical
quantity of a theory by a fixed combination of
several other quantities none of which has
separate empirical bearing.
=> Underdetermination as a proven theorem.
But the rephrased versions are completely depend-
ent conceptually on their respective originals.
Critics: The underdetermination thesis is either trivial
Underdetermination only obtains in general if no con-
straints of plausibility are placed on the necessary
Quine’s version of the underdetermination thesis
licenses recourse to what the critics would call “trivial
Nevertheless, the underdetermination thesis serves a
non-trivial epistemological function.
5. In Defense of Duhem-Quine Under-
Duhem-Quine underdetermination can be construed
as a positive claim about options left to scientific
theorizing by experience.
Empirically equivalent alternatives: no experience-
Yet the scientific community makes a choice in such
Scientists quite unanimously vote against nomo-
logical splits and deoccamized theories.
=> These choices are necessarily guided by non-
empirical virtues—in this cases “conceptual
Non-empirical values which are usually operative
in a hidden or implicit way are laid open in the
choice between empirically equivalent alternatives.
Underdetermination provides us with an opportu-
nity to elucidate in which sense the preferred
accounts are superior.
Duhem-type examples: competing real-life accounts
that were indistinguishable in empirical respect.
Struggle between Ptolemaic geocentrism, Coperni-
can heliocentrism and Tychonic geoheliocentrism in
late 16th century astronomy.
All three accounts yielded the planetary motions with
roughly the same accuracy.
Yet Copernican astronomy excelled in explanatory
power as regards the qualitative features of
Geocentric astronomy outperformed its Copernican
rival regarding its coherence with the accepted
The Tychonic compromise system preserved the
explanatory achievements of the Copernican
approach and remained in agreement with most of
the received physics and cosmology
=> (1) The scientific community did make a choice
between empirically equivalent alternatives and
(2) the criteria operative in this choice were
explanatory power and coherence with back-
Conventionality of physical geometry: alternative
space-time structures that are compatible with the
same set of spatiotemporal measurements.
Alternative accounts required the introduction of
force fields for which no sources could be identified.
Universal dismissal of these non-standard alterna-
tives by invoking the non-empirical criterion of the
preservation of causality.
Quantum mechanics: The picture behind Bohm’s
theory is at variance with standard quantum
mechanics, but the two are indistinguishable in
“Testability” militates against Bohm’s theory.
The historical fact is that the scientific community
does not rest undecided, wavering helplessly be-
tween different Duhem-Quine options. They rather
pick an account.
Theory choice goes beyond the austere hypothetico-
deductivist framework and bears witness to the
influence of non-empirical virtues.
6. Platonism and Aristotelianism as
Divergent Approaches to Nature
Model debate: The details of the phenomena
typically escape the grip of comprehensive theory.
However, the conceptual structure of the models
used for coping with the phenomena is typically still
shaped by general theory.
“Orifice problem” in hydrodynamics: amount of
liquid that streams out of a circular hole in a
Received treatment by invoking the conservation of
But in fact, the flow is considerably smaller.
Correction factor that varies with the profile of the
opening and is assessed empirically.
Possibility of replacing the combination of theoreti-
cal derivation and empirical adjustment by a
phenomenological approach which connects
directly the measured rates for various tanks and
A phenomenological approach and a theory-shaped
approach can easily come out empirically equivalent
and the preference for one of them is based on
The two approaches exemplify divergent attitudes
Platonism is committed to the rule of law; the uni-
versal is supposed to pervade the whole of nature.
Aristotelianism insists on the basic character of
=> The preference within the scientific community
for the theory-centered approach is not dictated by
7. The Invisibility of Underdetermination
Underdetermination is denied by many scientists and
philosophers of science: it is difficult enough to
identify one account that is in accordance with the
phenomena; thinking up an alternative is often
Whereas the freedom of choice has been over-
estimated by some philosophers and sociologists of
science, it has been underrated by many scientists.
Relevant arguments often invoke substantive
principles and methodological commitments; they
include the non-empirical values that Duhem-Quine
underdetermination places in the limelight.
The underdetermination thesis establishes a leeway
for science when faced with the verdict of nature.
The reason for the significance of this leeway is that
the criteria appealed to in picking an account from the
collection of empirically admissible options bear wit-
ness to our epistemological intuitions.
The pertinent non-empirical criteria uncover the
features of experience we consider worth knowing.
Epistemic values are constitutive of what we under-
stand by scientific knowledge.
They are the basis of normative judgments about the
adequacy of assessments within science.