The perils of smuggling metaphysics into science

Reading | Philosophy

A. A. Adedire, BSc, BA | 2024-11-10

Science is one of man’s greatest endeavors, characterized by its empirical methodology, stalwart practitioners and their histories, extensive accumulated knowledge, and resulting transformative technologies. Science is distinguished by its consistent, unyielding ability to humble the spirit of humans by forcing them to confront the vast expanse of their own ignorance. It is one of humanity’s steadfast tools that have proven potent in preventing our own folly and, indeed, in preventing our own demise. The demarcation of what does and does not constitute science has long been debated in various philosophical fields. However, juxtaposed with other avenues of inquiry, its definition becomes clearer. Science, as a systematic enterprise, is defined by reliance on observational and experimental evidence, the use of scientific hypotheses or proposed explanations of phenomena, the establishment of scientific theories or well-substantiated explanations of phenomena, self-evaluation through peer review, reproducibility, falsifiability, objectivity, and its cumulative knowledge.

In large part, this systematic enterprise attributes its success to its methodology. The scientific method is distinct from scientific values such as reproducibility, falsifiability, and objectivity, as well as from the body of knowledge it produces. Instead, it is a set of empirical precepts that lead to the acquisition of this knowledge. With some variations among fields, the scientific method involves proposing explanations of phenomena through observational evidence, then rigorously testing these explanations through iterative experimentation. Those explanations or hypotheses that survive are upheld and may become comprehensive, well-substantiated theories, which may again be subject to further refinement. The relationship between science and the world is also a point of contention that has long been debated. However, as an instrumental framework, science provides an intricate, elaborate description or prediction of the world and its behavior rather than a complete definition of what the world is.

As such, this is a limitation of scientific inquiry. Science provides a description or prediction of reality and how it behaves but does not give an all-encompassing definition of what reality truly is. The latter is the domain of metaphysical ontology, which is a branch of philosophy and not a mode of scientific inquiry. This important distinction cannot be overstated. Science, as a powerful tool of discernment, can lead to a more refined, objective description of reality through its ability to discard ontological claims, but it cannot wholly define reality. The claim “the world is made of physical matter” is an ontological assertion. The burden of proof lies with the claimant to produce evidence substantiating the claim. Scientific inquiry can be used to refute this ontological claim through an iterative empirical methodology, but science itself cannot produce its own ontological claims to fill the vacuum left by rejection.

A foundational limitation of all scientific inquiry is that it rests on general assumptions about the subject of study, such as the consistency of natural laws or the non-random behavior of systems. These assumptions themselves may or may not be subject to direct empirical scrutiny; however, unavoidably, attempting to scrutinize every assumption would lead to an infinite regress. Science is confined by the scope of what can be observed, measured, and tested. It is also limited by its predictive power, as complex, chaotic systems may not be easily resolved. Scientific inquiry is subject to interpretation, bias, ethical and practical considerations, and paradigm dependence. Here, “paradigm dependence” is meant in the Kuhnian sense: the way a question is asked is subject to the current scientific framework in which it is being asked, as certain general assumptions are granted as evident. Hence, scientific values are meant to mitigate these limitations—reproducibility addressing predictive limitations, falsifiability addressing ontological limitations, and objectivity addressing interpretive limitations.

Physicalism is a philosophical worldview asserting that all that exists can be reduced to quantifiable physical interactions, while acknowledging immaterial fields or forces that supervene on the physical. As historians have recounted, it traces its origins to Greek and Roman atomists countering the philosophical claims of Parmenides, the originator of Western metaphysical ontology. It is a philosophy built on each successive epoch’s interpretation of Greek and Roman naturalism, and it was developed through scholarly edification based on internal consistency and past refutations. In a word, it does not bear the characteristic hallmarks of a science: self-evaluation through peer review, reproducibility, falsifiability, objectivity, and cumulative knowledge. It is first and foremost a philosophy that can be sharply demarcated from scientific inquiry.

Physicalism defines what reality truly is, and through this definition, it proceeds to fit the observed behaviors of reality onto its invented definition. The acquiescence of physicalism within the broader cultural milieu allows for the smuggling of assumptions into scientific inquiry, which are then, in a circular manner, considered to be validated by science itself. This disastrous interplay perpetuates a continued myopia in distinguishing between the ontological claims of physicalism and the assumptions of scientific inquiry. Science, as a tool of discernment, can be brought to bear on the claims of physicalism but will never provide a ready-made ontology, as this is by definition non-science.

It can be said that philosophy begins where empirical observations are limited, and science begins where they are abundant. However, the two disciplines often inform and complement one another. The nature of philosophical inquiry is inherently speculative and conceptual, as it grapples with broad, often abstract questions that frequently lie beyond the realm of direct observation and empirical testing. Philosophy is distinct from science, but its tools are invaluable. Philosophical theories are evaluated not through experimentation, but by assessing their logical consistency and their strength of argumentation. Philosophy was forged in the crucible of reasoned wonderment about the ordinary and through the close examination of what is perceived as nature’s givens. Ontology itself gestated in the writings of pre-Socratic thinkers and was only fully conceived as a singular insight through deep introspection, sharing in this respect much with religious mysticism. This introspective approach to understanding reality has led to various ontological theories throughout history, each attempting to provide a comprehensive framework for understanding humanity and its place in the cosmos. Among these, physicalism stands out as the natural metaphysical ontology. As such, its core tenets must be clinically scrutinized. Let us not be coy as to what it is: a philosophical worldview.

Again, physicalism presents itself as a natural ontology, grounded in the observation of a world that has clear spatial and temporal boundaries. This world is unified and operates according to natural laws. Although this world is experienced subjectively, its properties and phenomena are verified objectively through empirical measurement. Furthermore, these assumptions about the world are reinforced by the cumulative nature of analogous experiences. Consequently, physicalism is often seen as supported by the physical sciences. Indeed, a key argument for physicalism is the argument from the success of the physical sciences, which proceeds as follows: The physical sciences have consistently provided reliable, verifiable, and predictive explanations of the world. Over time, disciplines that were once thought distinct and governed by separate principles have now been shown to be interconnected and reducible to more fundamental physical principles; the biological sciences have become integrated with the chemical sciences, and the chemical sciences have become integrated with the physical sciences. Historically, poorly understood phenomena once thought to be non-physical, along with their accompanying outmoded explanations (such as vitalism, luminiferous aether, and energeticism), have been superseded by the physical sciences, which do not find it necessary to invoke non-physical explanations. Therefore, physicalism must be true due to the distillation of various scientific disciplines into more fundamental physical principles and its demonstrated success in describing the natural world.

However, the argument from the success of the physical sciences faces numerous problems. A fundamental limitation of scientific inquiry is its reliance on assumptions about the nature of the world, such as the constancy of natural laws. These assumptions within physical science are themselves ontic presuppositions of physicalism. So, the argument that the success of the physical sciences supports physicalism begs the question, assuming the conclusion in its premises. The sciences are not monolithic in their working theoretical conclusions; accordingly, some aspects do not substantiate physicalism or may even contradict it. For instance, quantum mechanics introduces concepts that challenge classical notions of physicalism and physical realism, such as non-locality, wave-particle duality, and entanglement. There could be aspects of reality that are non-physical, do not fundamentally supervene on physical matter, and elude measurement. Indeed, there are known phenomena that resist reduction to purely physical terms, such as consciousness and meaning. As perennial philosophical insights have suggested, humans could be deceived by the apparently physical nature of reality.

Physicalists may acknowledge the possibility of non-physical aspects of reality but maintain that there is no empirical evidence to support such claims, arguing that the physical world is causally closed. This means that every physical event has a sufficient physical cause. Thus, the inclusion of non-physical causes is deemed superfluous, as these causes are empirically inaccessible. Physicalists defend their position’s simplicity in reducing the world to a single substance. Additionally, they argue that non-physical ontologies struggle to explain how the non-physical interacts with the physical. Physicalism avoids this problem by positing that all interactions are physical, thereby providing a clear, concise, and internally consistent account of causation.

The strength of these converging lines of argumentation is contingent upon how matter is defined. Physicalism’s central assertions are compromised by its failure to provide a robust definition of physical matter. As an ontology, physicalism defines physical matter as the fundamental datum of reality, which is distinct from the definition given by classical physics, where “matter” refers to that which occupies space and has mass—the latter being an element in a broader empirical framework used to describe and predict how reality behaves. Given physicalism’s definition of matter, several questions arise: Are there multiple kinds of physical matter or only one? Is matter eternal? Is it discrete? Does it have a minimal constituent? Is it capable of expressing multiple forms? Are its properties intrinsic? Are these properties expressed through its interaction or merger?

Furthermore, this philosophical worldview is superficially simple. Physicalism does not reduce the world but rather doubles it by positing two distinct realms: subjective experience and an external world. As one perceives the world through the faculty of awareness, there are only two things of which one can be assured: the very act of awareness and its intentionality—its aboutness or directedness. The world as a tangible external is not a given—this being a topic of lively philosophical debate, notably reaching its climax in 1637, marked by the famous Cartesian dictum. Physicalism posits a palpable external world alongside the subjective perception of the world, even though the latter is the only true given; it then proceeds to denigrate perception and elevate an invented reality conjured from nothing. It hijacks the language of science, having usurped its foundational assumptions, by claiming that all dimensions of measurement, once divorced from the contaminants of subjectivity, represent a true reality, a pure reality finally sanitized.

And yet, the subjective, qualitative experience of being persists as an irreducible phenomenon. The “what it’s like” quality of experience suggests a process beyond mere physicality. How does the ostensibly inert, mechanical world produce the richness of qualitative perception? The various objections to physicalism (e.g., the hard problem, the inverted spectrum, Mary’s room, and the explanatory gap) hinge on this single point of contention: can physicalism provide a complete account of consciousness? While physicalism purports to offer a simple, coherent, and natural worldview, it faces significant rebuttals. Enduring philosophical objections suggest that physicalism falls short in fully explaining the most immediate aspect of our existence: consciousness itself.