The Problem of Holism: A Critical Examination of Popper’s Falsifiability Criterion
Karl Popper’s philosophy of science, centred on the principle of falsifiability, has profoundly influenced scientific methodology by providing a seemingly clear and objective criterion for distinguishing science from non-science (Sfetcu, 2019). According to Popper, a theory is scientific if, and only if, it is falsifiable - if it can be tested and potentially refuted by empirical observation (Popper, 1959). This framework has been widely praised for its simplicity and its portrayal of science as a dynamic process of bold conjectures and rigorous testing, which contrasts with pseudo-scientific ideas that are insulated from falsification (Popper, 1959; Mitra, 2020). However, this simplicity has also attracted significant criticism, with the most compelling objection stemming from the problem of holism (Godfrey-Smith, 2009).
Holism highlights the fact that scientific theories are never tested in isolation; rather, they rely on a web of auxiliary assumptions and background knowledge to connect theoretical predictions with empirical observations (Duhem, 1962). This interdependence creates ambiguity in falsification, as a failed prediction might reflect a flaw in an auxiliary assumption rather than in the core theory itself (Godfrey-Smith, 2009). Consequently, Popper’s claim that falsifiability serves as a definitive marker of scientific theories is called into question. If falsification cannot decisively refute a theory without ambiguity, the boundary between science and non-science becomes blurred, undermining the objectivity of Popper’s demarcation criterion (Godfrey-Smith, 2009).
This essay will examine holism as the central challenge to Popper’s view of science, explore his response to this objection, and evaluate the effectiveness of his proposed solutions. It will argue that while Popper’s emphasis on critical scientific behavior and his acknowledgment of the conjectural nature of auxiliary assumptions offer valuable insights, his response ultimately fails to resolve the logical and practical issues posed by holism. By focusing on normative ideals of scientific conduct rather than providing a robust solution to the problem, Popper shifts the discussion away from the original goal of identifying a clear and objective criterion for demarcation.
The following argument will explore how the problem of holism fundamentally challenges Karl Popper’s falsificationism framework by demonstrating the complexities involved in testing scientific theories. Drawing on the insights of philosophers like W.V.O. Quine and Peter Godfrey-Smith, this argument will illustrate that no scientific hypothesis can be tested in isolation, as it is embedded within a network of interconnected assumptions (Quine, 1992). Consequently, the apparent falsification of a theory may stem not from the theory itself but from flaws in these auxiliary assumptions, thus complicating Popper’s conception of falsification and demarcation (Godfrey-Smith, 2009).
The most significant objections to Karl Popper’s view of science is rooted in the problem of holism, which challenges the very foundation of Popper’s falsificationism framework (Godfrey-Smith, 2009). Holism, in the context of scientific testing, refers to the idea that any attempt to test a scientific theory inevitably relies on a network of auxiliary assumptions (Quine, 1992; Godfrey-Smith, 2009; Wagner, 1986). These auxiliary assumptions are necessary for bringing a theory into "contact" with empirical observations (Quine, 2000). For instance, when testing the claim that “iron expands when heated,” one must assume that the sample being tested is indeed iron, that the measurement instruments accurately record temperature and expansion, and that the environmental conditions of the experiment are not interfering with the results (Godfrey-Smith, 2009). If the observed result contradicts the theoretical prediction - if, for example, the iron appears to contract when heated - it is not immediately clear whether the theory itself is at fault or whether one of the auxiliary assumptions has failed (Godfrey-Smith, 2009). Therefore, this interdependence between theories and auxiliary assumptions complicates the concept of decisive falsification, which is central to Popper’s philosophy, since these assumptions are integral to any scientific test, the reasons behind a theory’s success or failure can be varied and complex (Godfrey-Smith, 2009).
To explain this aforementioned point, the reason why this ambiguity challenges Popper’s falsificationism framework is because, central to Poppers view of science is the notion that theories have the form of generalisation’s, and they take risk by prohibiting certain kinds of particular events from being observed (Popper, 1959; Mitra, 2020). If we believe that all pieces of iron, of whatever size and shape, expand when heated, then our theory forbids the observation of something that we know to be a piece of iron contracting when heated (Godfrey-Smith, 2009). A problem may have occurred to you: how sure can we be that, if we see a piece of “iron” contracting when heated, that it is really iron? We might also have doubts about our measurements of the contraction and the temperature change. Maybe the generalisation about iron expanding when heated is true, but our assumptions about the testing situation and our ability to know that a sample is made of iron are false (Godfrey-Smith, 2009). Whenever we try to test a theory by comparing it with observations, we must make a large number of additional assumptions in order to bring the theory and the observations into “contact” with each other (Verhaegh., 2017; Quine, 2000). If we want to test whether iron always expands when heated, we need to make assumptions about our ability to find or make reasonably pure samples of iron (Godfrey-Smith, 2009). If we observe an unexpected result (iron contracting on heating), it is always possible to blame one of these extra assumptions rather than the theory we are trying to test (Godfrey-Smith, 2009).
Thus, the problem of holism impacts Popper’s view of science in many manifold ways: firstly, it highlights a strong degree of ambiguity pertaining to the falsification criterion for demarcating science from nonscience, as falsification is rarely definitive (Thornton, 2007; Zhou, 2024). Thus, what Popper envisioned as a clear and objective process for distinguishing scientific theories – namely that scientific theories can be falsified, whereas pseudo-scientific theories can’t be falsified - becomes muddied by the practical realities of testing, where auxiliary assumptions can always be questioned or adjusted to preserve a theory (Godfrey-Smith, 2009). If failed tests do not unambiguously falsify a theory, scientists may choose to revise or reject auxiliary assumptions instead, which makes it difficult to determine when a theory should be abandoned (Godfrey-Smith, 2009). This means that the supposed risk-taking nature of scientific theories, central to Popper’s philosophy, is often mitigated by the flexibility inherent in scientific practice, undermining his claim that falsifiability provides a definitive and reliable marker of scientific ideas (Godfrey-Smith, 2009).
Popper responded to the problem of holism with two key arguments. First, he acknowledged that scientific testing relies on interconnected assumptions but argued that these auxiliary assumptions are conjectures that can be independently tested and scrutinised to identify specific issues (Zhou., 2024; Godfrey-Smith, 2009). Secondly, he emphasised the importance of scientists adopting a critical and open-minded approach, exposing their theories to genuine risk and avoiding ad hoc modifications (Godfrey-Smith, 2009). Popper believed that this commitment to critical inquiry would enable science to navigate the complexities of holism and continue to progress.
To focus on the first issue, is the problem of auxiliary assumptions which are baked within scientific theories; this means that, as noted beforehand, that when an observation fails to align with the predictions, there remains the possibility that the fault lies not with the theory itself, but instead with one of these auxiliary assumptions (Godfrey-Smith, 2009). Thus, Popper argues that the solution to this problem was simple: Popper believed that the extra assumptions needed to connect theories with testing situations – these themselves are also additional conjectures too, and thus we can test these conjectures separately (Godfrey-Smith, 2009; Zhou., 2024). In this sense, Popper viewed the entire scientific process as an interconnected web of conjectures, each of which must be critically scrutinised and potentially falsified (Zhou., 2024). By performing experiments that attempt to falsify or refute these conjectures, we can then find out which one of the subsystem are causing the failure in prediction (Zhou., 2024).
Moreover, Popper asserted specific qualities of a scientists behaviour, and how their behaviour should be orientated to embrace the spirit of critical inquiry, through willingly exposing their theories to genuine risk and thus refraining from deflecting criticism by attributing failures to external factors unless compelling evidence justifies doing so (Godfrey-Smith, 2009; Thornton, 2007). Popper said that a scientist must have a set of traits and behavioural qualities in order to successful overcome the problem of holism (Godfrey-Smith, 2009). Popper believes that for science to progress successfully, scientists should adopt a critical attitude towards their hypotheses and not hold attitudes that are dogmatic (Zhou., 2024). Through this critical attitude and mindset, theories can be constantly tested for errors and attempts can be made to falsify them whenever possible (Zhou., 2024; Godfrey-Smith, 2009). Moreover, Popper argued that attempts to “save” or “hold onto” a hypothesis, theory or belief by introducing ad-hoc changes or hand-waving anomalies and falsifying evidences to “immunise” the old theory hinders scientific development and should not be encouraged (Godfrey-Smith, 2009; Zhou., 2024).
To address Popper’s first response pertaining to the web of auxiliary assumptions – each of these auxiliary assumptions themselves being conjectures and thus open to refutations - a central weakness is apparent. This is because, the constant possibility of questioning and revising auxiliary assumptions creates an endless cycle of deferrals, preventing the definitive falsification of a core theory and undermining the clarity and reliability of Popper's falsification criterion (Godfrey-Smith, 2009; Zhou., 2024). As mentioned above, one of Popper’s arguments to get around the issue of holism is to suggest that, the auxiliary assumptions themselves that are baked within scientific theories – these auxiliary assumptions are themselves conjectures, and thus can be refuted in isolation (Zhou., 2024). In this sense, Popper viewed the entire scientific process as an interconnected web of conjectures, each of which must be critically scrutinised and potentially falsified (Zhou., 2024). A criticism of Popper’s response, however, is that there cannot even be any proper work done in science if scientists give up on their theories too easily, as dogma allows for scientists to engage in meaningful debates (Zhou., 2024). Without a certain level of dogma, scientists would too easily reject a theory and not be able to discover more things inherent within a theory that can be used to reach a better one (Zhou., 2024). Popper’s answer to this starts off by acknowledging the importance of a slight amount of dogma and accept the fact that scientific debate is still important to the growth of science (Godfrey-Smith, 2009). Following that, he states that he “did not propose the simple rule: ‘Look out for refutations, and never dogmatically defend your theory’.” Popper here moves to a less-strong stance and notices the usefulness of a limited amount of dogma in scientific progress (Godfrey-Smith, 2009). Although he does still hold that a radical critical attitude is better than a radical dogmatic attitude, Popper agrees that a healthy scientific community should consist of some of each, albeit the extent of dogmatic attitude should be kept to a certain threshold, just enough to allow for debates and defence but not cause scientists to be inclined to generate ad-hoc hypotheses to “save” their theories (Godfrey-Smith, 2009). Popper’s ultimate stand on the topic, however, is still that of a critical stance, stating that one should never attempt to evade problems and be self-critical as much as we are critical to others (Zhou., 2024).
Yet, the most significant weakness in Popper’s response is his failure to provide a guarantee of objective falsification, which undermines his claim of offering a definitive criterion for demarcation (Godfrey-Smith, 2009). If every falsification process depends on subjective decisions about the validity of observational reports and auxiliary assumptions, then the demarcation between science and non-science becomes contingent on the judgment of individuals rather than the inherent properties of theories (Godfrey-Smith, 2009). This is a significant problem for Popper’s theory of science because it challenges the objectivity and universality of his demarcation criterion, reducing it to a matter of subjective interpretation rather than a definitive philosophical standard (Godfrey-Smith, 2009). If falsification ultimately depends on human judgment regarding which components of a theory to question or revise, the supposed boundary between science and non-science becomes fluid and context-dependent, undermining the rigor and reliability that Popper aimed to establish (Godfrey-Smith, 2009).
Vitally, to evade this issue, Popper argues that a “good” scientist must be imbued with a set of characteristic traits, and thus through these traits shall avoid “holding onto” a theory, unless there is good reason to do so (Godfrey-Smith, 2009). Yet, Popper acknowledges an issue with this theorisation: logic alone cannot compel a scientist to abandon a theory in the face of contrary observations (Godfrey-Smith, 2009). It is always possible, at least in principle, to attribute the failed prediction to one of the auxiliary assumptions rather than to the theory under scrutiny (Godfrey-Smith, 2009). Thus, a critical weakness in Popper’s response concerns the subjectivity of observational decisions. Popper’s acknowledgment that the acceptance of an observation report is ultimately a “decision” made by scientists raises troubling implications for his philosophy (Godfrey-Smith, 2009). If such decisions are inherently subjective and influenced by factors such as theoretical commitments, experimental conditions, or personal biases, they risk undermining the objectivity that Popper sought to preserve in the falsification process (Godfrey-Smith, 2009). This subjectivity creates ambiguity in distinguishing between science and pseudo-science, as for instance, proponents of pseudo-scientific theories might accept observational reports that align with their views while rejecting those that contradict them, using the same freedom of decision-making that Popper allows for scientists (Godfrey-Smith, 2009). While Popper argued that a genuine scientist would avoid such practices, this reliance on normative behavior does little to safeguard against the misuse of his framework or to ensure that falsification retains its role as a decisive criterion. The focus on normative behaviours of scientists is key here, as it doesn’t seem clear that Popper’s argument adequately addresses the holism objection. Instead, what Popper appears to do is shift focus - from identifying a defining characteristic of scientific theories to emphasising key traits of scientific behavior (Godfrey-Smith, 2009). In doing so, he evidently steps back from his original goal of pinpointing what makes scientific theories themselves distinctive, vitally raising concerns for Popper’s worldview of science (Godfrey-Smith, 2009).
Therefore, a few central issues here are present pertaining to Popperian’s conceptualisation of science, indicating how Popper does not overcome the issues of holism successfully. One major flaw lies in Popper’s reliance on the notion of “good scientific behavior” to address the problem of holism. While Popper’s portrayal of the ideal scientist - someone who actively seeks to falsify their own theories and avoids ad hoc adjustments - provides a compelling ethical ideal, it does not resolve the logical challenges posed by holism (Godfrey-Smith, 2009). The interconnected nature of testing means that any failed prediction can always be attributed to auxiliary assumptions or experimental errors rather than the core theory itself (Mitra, 2020; Godfrey-Smith, 2009). Although Popper acknowledged this and argued that auxiliary assumptions should also be tested, his reliance on the normative principle that a good scientist would prioritise genuine risk-taking and avoid deflecting criticism offers no logical resolution to the ambiguity inherent in testing (Mitra, 2020). Instead, this response shifts the discussion from the structure of scientific theories to the virtues of scientific behavior, leaving unanswered the central question of how falsification can function as a definitive criterion for demarcating science from non-science (Godfrey-Smith, 2009). This response shifts the focus of Popper’s philosophy in a fundamental way as initially, Popper sought to define a distinguishing feature of scientific theories - namely, their falsifiability. Yet, his acknowledgment of holism leads to a reorientation of his philosophy toward describing the behavior and mindset of scientists (Godfrey-Smith, 2009). Popper emphasises that the hallmark of good science lies not only in the logical structure of theories but also in the intellectual virtues of scientists: their willingness to take risks, subject their ideas to rigorous testing, and avoid ad hoc adjustments that merely preserve a failing theory without enhancing its explanatory power (Thornton, 2007; Mitra, 2020; Godfrey-Smith, 2009). While this shift enriches Popper’s account of science by incorporating a normative vision of scientific conduct, it centrally marks a retreat from his original goal of offering a purely logical criterion for demarcating science from non-science, thus indicating that Popper fails to overcome the challenges posed against the Popperian’s view of science (Godfrey-Smith, 2009).
In conclusion Popper fails to overcome the challenges associated with his theory. The most significant objection to Popper’s philosophy of science lies in the problem of holism, which fundamentally challenges his claim that scientific theories can be decisively falsified, and that falsifiability serves as a clear and objective criterion for distinguishing science from non-science (Godfrey-Smith, 2009). Holism demonstrates that the testing of any scientific theory depends on a network of auxiliary assumptions, creating ambiguity about whether a failed prediction falsifies the core theory or the supporting assumptions (Quine, 1992). This undermines the simplicity and reliability of Popper’s framework, revealing that scientific inquiry is far more iterative and flexible than his strict falsification model suggests.
Popper’s response to this objection - arguing that auxiliary assumptions are themselves conjectures that can be independently tested and emphasising the ideal scientist’s critical and open-minded behavior - offers valuable insights into the ethos of scientific inquiry. His focus on intellectual integrity, rigorous testing, and resistance to ad hoc modifications aligns with the core principles of scientific progress. However, his response fails to resolve the logical ambiguities introduced by holism (Quine, 1992; Godfrey-Smith, 2009). By shifting the emphasis from the structure of scientific theories to the behavior of scientists, Popper ultimately retreats from his goal of providing an objective and definitive demarcation criterion (Godfrey-Smith, 2009).
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