Beyond Reductionism: The Limits of Scientific Explanation

A reflection on J.A. Fodor's Special Sciences:

In the paper, Special Sciences, J.A. Fodor argues that reductivism is too strong a constraint on the unity of science. He argues in favor of the weaker token physicalism, which preserves the desired consequences of reductivism while allowing for the unity of science.

Reductivism (also known as reductionism) in science is the view that all special sciences (i.e. all sciences except physics) can be reduced to physics. That is, any event in the special sciences can be adequately explained by a physical event. It is often assumed, for example, that psychology can be reduced to physics via neurology, biology, biochemistry, and chemistry. Psychological events can be explained in terms of neurology, neurological events can be explained in terms of biology, and so on, all the way to physics. In reductivism, concepts from special sciences can be reduced in this manner via bridge laws, which are meant to express “identities.” For instance, consider x behavior (a psychological concept) and y pattern of neuronal activation in the brain (a neurological concept). In reductivism, a bridge law (written ‘x ↔ y’) would imply that x behavior is always and only caused by y pattern of neuronal activation, and that y pattern of neuronal activation always and only causes x behavior. This type of relation is known as a type-to-type correlation, a 1-to-1 match.

Token physicalism in science is the view that all events that all sciences talk about are physical events. This interpretation is weaker than reductivism in that reductivism requires type-to-type correlation, whereas token physicalism does not. Consider the previous example of x behavior and y pattern of neuronal activation. In token physicalism, there does not need to exist the 1-to-1 match as was required in reductivism. Instead, for example, x behavior may be caused by a, b, or c patterns of neuronal activation, whether between individuals or within one. In our special sciences, there does not always exist a 1-to-1 match, especially in fields like psychology. The same behavior, emotion, or thought may result from a variety of different situations, each with a distinct pattern of neuronal activation. In such cases, the psychological concept can be explained in terms of neurology, but its entire essence (e.g. the emotion of happiness) cannot be captured with neurology alone. Along the same lines, Fodor mentions that economics cannot be reduced to physics, but that a wide range of physical phenomena could account for economic events. He explains that this provides support for token physicalism, rather than reductivism. In order to prove reductivism, rather than mere token physicalism, one would need to map all of the neuronal firing patterns or physical events to their corresponding psychological or economic events. However, even if this were possible, again, the entire essence of the psychological phenomenon would not be adequately captured.

Fodor mentions that there are two main reasons to believe that token physicalism is a more accurate representation of science than reductivism. First, token physicalism recognizes the inherent complexities and nuances present in the special sciences by allowing exceptions in the laws governing them. He argues that if one were to take the strict reductionist stance, it is challenging to account for minute physical deviations in the context of fields like psychology or economics. Second, the very existence of special sciences is a testament to their unique contributions to understanding the natural world. If everything could truly be reduced to physics, there would be no need for any of the special sciences, including psychology and economics. Ultimately, these fields offer explanations for the manifestations of a myriad of distinct physical events, and they exist because they offer insights that could not be fully appreciated in the context of physics. He continues by arguing that even if fields like psychology or economics could be reduced to mere physics, it is unlikely that the language of physics would be able to concisely account for observations in those fields.

Overall, Fodor prefers the weakest view, token physicalism, and argues that reductionists should really be token physicalists. He contends that a strict adherence to reductivism limits our understanding of reality, as it fails to account for the complexities inherent in the special sciences. While physics may lay the foundation for scientific inquiry, it is through the special sciences that we gain a fuller, more nuanced understanding of the natural world.

However, I am inclined toward a broader perspective that synthesizes Kant’s transcendental realism with Christian thought. Kant’s transcendental realism acknowledges that while we experience reality through the structures of our perception and cognition, there exists a noumenal realm beyond empirical observation—a realm that reductionism cannot fully capture. This perspective aligns with Christianity’s affirmation of a reality that transcends the physical, recognizing the existence of both material and spiritual dimensions.

An example that illustrates the limitations of both reductivism and token physicalism can be found in the study of human consciousness. While neuroscience can identify neural correlates of thought, emotion, and self-awareness, it cannot fully explain the subjective experience of being (i.e., qualia). Token physicalism acknowledges the complexity of these experiences by allowing for multiple neurological pathways to correspond with a given mental state, but it does not address why subjective experience exists at all. Kantian transcendentalism provides a richer framework by suggesting that consciousness itself is not just an emergent property of neural activity but a fundamental condition of knowledge, shaping how we interpret reality. Christianity further deepens this perspective by asserting that consciousness is not merely a byproduct of material processes but a reflection of the divine, rooted in the soul’s relationship with God. Together, these perspectives suggest that human experience cannot be fully understood through physical explanations alone; rather, it requires recognition of both the structures of human cognition and the existence of a transcendent order that imbues life with meaning and purpose. By integrating these perspectives, I argue that a truly comprehensive understanding of the world must go beyond token physicalism and incorporate not only the insights of the special sciences but also the recognition of transcendental and divine realities that give meaning to human experience.