The Duhem-Quine thesis, also called the underdetermination proposition, is a popular philosophy and sociology of science assertion. The epistemic challenge arising from it is not limited to the scientific context. Rather, it remains readily perceptible in classical skeptical knowledge attacks. For example, Rene Descartes famously undertook to disprove his knowledge of things by supposing the existence of an Evil Demon whose only aim was to cause worldwide deception. Descartes’ challenge appeals to an underdetermination variety by suggesting that people’s sensory processes would remain the same if the Evil Demon (and not the physical, external world) caused them.
Similarly, the 1955 “New Riddle Induction” by Nelson Goodman ignites the idea that the existing evidence of tangible things and general knowledge could support inductive generalizations that are principally different from those they normally support, thereby producing radically variable consequences for future events. The Duhem-Quine thesis is a simple and familiar two-versioned predicament that is important for measuring and examining scientific and general knowledge derived from experimental and other investigations.
To understand the meaning and importance of the Duhem-Quine thesis, it is important to consider the history of its traditional locus classicus. The thesis is obtained from the separate but related works of Pierre Maurice Marie Duhem and Willard Van Orman Quine. Particularly, the French physicist, historian, and philosopher P.M.M. Duhem formulated various scientific underdetermination problems in especially compelling and perspicuous ways in his seminal works “The Aim and Structure of Physical theory” and “Physical Theory and Experiment.” Surprisingly, Duhem himself argued that these problems created serious challenges to scholars’ efforts to ascertain physics’ theories.
In the mid-20th century, the American philosopher and logician W.V.O Quine suggested that the challenges identified by Duhem applied to all knowledge claims, not just scientific theories. Thus, Quine’s treatment and further development of Duhem’s assertion became an important component of human knowledge’s general account. However, neither Duhem nor Quine systematically distinguished between the contrastive and holist forms of underdetermination, even though these two varieties are discernible in Duhen and Quine’s independent works.
Holist underdetermination is one of the profoundly distinct forms of the Duhem-Quine thesis. It arises every time the failure to test a hypothesis in isolation causes underdetermination in responding to disconfirming pieces of evidence such as a failed forecast. In other words, because hypotheses contain empirical consequences only when they operate based on some other hypotheses as background information, a falsified empirical implication or a failed prediction typically makes it blaming and possibly abandoning one or all of the background pieces of information underpinning the prediction open to the knowledge seeker (Duhem “The aim and structure of physical theory” 77).
Notably, the scholar or any other knowledge seeker will opt to abandon the auxiliary hypothesis or background information rather than the hypothesis they sought to test for various reasons. Particularly, “as long as the experiment lasts, the theory should remain to wait, under strict orders to stay outside the door of the laboratory” (Duhem “Physical Theory and Experiment” 258). Essentially, the auxiliary hypothesis must remain silent and never distract the knowledge seeker.
After all, “the demonstrative value of the experimental method is far from being so rigorous or absolute: the conditions under which it functions are much more complicated than is supposed in what we have just said: the evaluation of results is much more delicate and subject to caution” (Duhem “Physical Theory and Experiment” 261). The unfortunate thing is that when an empirical prediction proves falsified, the experimenter will not know where the problem lies. Indeed, the issue could lie with the original hypothesis that the researcher seeks to test, or it could be within the other assumptions and background information used in the failed forecast.
Contrastive underdetermination is the other fundamental form of the Duhen-Quine thesis. It involves the probability that each body of available evidence confirms more than one theory. That is to say, even though a particular piece of evidence confirms some theory that the author sought to understand, that particular piece of evidence might also confirm other theories that the scholar or knowledge seeker may or may not know. Even when the researcher suspends concerns arising due to holist underdetermination, there is the second variety which is still an obstacle to theoretical science’s truth discovery. That second variety – the contrastive form – questions the evidence’s ability to confirm any hypothesis and compares it to possible alternatives and their supposed characters.
The contrastive variety of the Duhem-Quine thesis raises fundamentally different concerns compared to what the holist version does. Indeed, this fact is clearly perceptible in Duhem’s writing. For example, referring to the Foucault’s experiment, Duhem notes that People will be mistaken to “attribute to Foucault’s experiment so simple a meaning and so decisive an importance; for it is not between two hypotheses, the emission and wave hypotheses, that Foucault’s experiment judges trenchantly; it decides rather between two sets of theories each of which has to be taken as a whole, i.e., between two entire systems, Newton’s optics and Huygens’ optics” (Duhem “Physical Theory and Experiment” 265).
Evidently, although the two-versioned Duhem-Quine thesis is an uncomplicated and customary predicament, it merely scrapes the top of the multiple manners in which underdetermination problems may arise during scientific and general knowledge investigations.
The underdetermination theory is a significant assertion about the experimental testing of theories. From the discussion, it is evident that no logical simplicity exists in the experimental testing of theory despite contrary opinion. Thus, the Duhen-Quine thesis postulates that, in principle, numerous theories fitting an observed fact, more or less sufficiently, may exist. The proponents of the thesis argue that, in the face of any evidence, one can maintain any theory provided that they make adequately radical changes elsewhere in their beliefs. The thesis also suggests that one must invoke social factors to explain an individual’s adoption of a given theory. In this regard, at the thesis’ core is the idea that any available evidence at any given time may not be enough to help one determine the beliefs they should hold.
As such, if a mother spends $10 on bananas and mangoes, and that bananas cost $1 each while mangoes cost $2 each, then it is clear that the mother did not buy six mangoes. However, it is not clear if she bought eight bananas and one mango. This conundrum is the same principle behind the popular and sensible methodological declaration that “correlation does not imply causation” (Duhem “Physical Theory and Experiment”428). The thesis has two fundamentally different forms. Regardless of the form, the thesis plays a crucial role in scientific and non-scientific investigations as it shows that hypothesis testing in isolation is impossible. In other words, no scientific or other postulation can – individually and by itself – predict the truth.
Duhem, Pierre Maurice Marie. “Physical Theory and Experiment”, in M Curd, Martin, and Jan A. Cover. Philosophy of science: The central issues. Norton, 1998, pp. 257-280.
Duhem, Pierre Maurice Marie. The aim and structure of physical theory. Vol. 13. Princeton University Press, 1991.