Is Biology Autonomous from the Physical Sciences?

Background of the Debate

Biological science has undergone a period of progressive change in the last few decades. A distinctive element of this progress has been the continuous addition of fresh theoretical perspectives and methods from physics and chemistry — the physical sciences. The most interesting recent innovations in contemporary biology are closely linked with how these new theories and methods are applied. There is broad consensus that many phenomena that once occurred naturally within the arena of biological science have been overtaken by a science that is practically physical. The explicit reference of newly expanded fields such as "biophysics," "biochemistry," and molecular biology apparently points to new frameworks for treating the science of life on earth according to chemical and physical principles (Hansen, 1969).

What Is Biology?

In attempting to answer this question, it is worth noting that biology is, in actual fact, composed of two distinct and separate fields: historical biology and mechanistic or functional biology. All activities related to the physiology of living organisms fall under functional biology, particularly in relation to cellular processes where the genome is concerned. It is noteworthy that all these cellular functions can find adequate explanation in purely mechanistic, physical, and chemical terms.

The other biological branch is historical in character, and purely functional processes cannot be explained by knowledge of history — much as this knowledge is important for explaining general aspects of the living world when the theory of evolution is taken into account. The type of questions most frequently asked also distinguishes these two fields of biology. The most commonly asked question in functional biology is "how?" while in evolutionary biology the frequently asked question is "why?" Even so, the distinction is not absolute, because even in evolutionary biology one occasionally asks "how" questions — for example, how can one explain the multiplication of species? One must therefore take note of the essential differences between the two classes of biology in order to understand its remarkable nature. Indeed, some of the most distinctive differences between biology and the physical sciences hold true for only one of its branches, namely evolutionary biology (Mayr, 2004).

How the Reductionism Debate Began

Up to the nineteenth and twentieth centuries, biology was practically a marginal subject. Despite the fact that an enormous body of factual knowledge in natural history, physiology, and anatomy was gathered in the seventeenth and eighteenth centuries, it was widely believed that the world of life during that period belonged purely to the medical realm. However, this was only true for physiology and anatomy, and in some cases botany, which to a large extent comprised identifying plants with medicinal value. Important elements of natural history were in practice either regarded as a hobby or as an expression of natural theology. When mechanics was recognized as an exemplary science, a new school of thought emerged holding that organisms were essentially the same as inert matter (Mayr, 1997).

The logical conclusion drawn from this assumption was that the prime objective of science was to subjugate biology to the laws of physics and chemistry. With the passage of time, however, progress in biology rendered this theory untenable. Biology gained a stronger foothold in the scientific sphere when vitalism and its counterpart, mechanism, were overtaken by the acceptance of the new theory of organicism in the twentieth century — this despite the fact that many philosophers of science had not yet fully accepted the impact of this new paradigm (Mayr, 1997).

Three very distinct views on the position of biology among the sciences emerged from the mid-twentieth century. One extreme position held that biology should not be regarded as a science because it lacks the universally accepted quantitative and structured laws of a "true science," with physics serving as the reference point. At the opposite end of the spectrum, biology not only shares the qualities of a true science but differs from physics in essential ways that rank it as an autonomous science in its own right. Between these two opposing views, a third position regards biology as a "provincial science" on the grounds that its findings are ultimately reducible to the laws of chemistry and physics and are therefore not universal (Mayr, 1997).

Is Biology an Autonomous Science?

The question of whether biology is an autonomous science can be framed in two ways: Is biology, like chemistry and physics, a genuine science? And does biology share similar characteristics with chemistry and physics? John Moore's eight criteria for evaluating whether a given discipline deserves to be called a science can help answer the first question. According to Moore: (1) the basis of science should be actual data collected in the field and subjected to laboratory experimentation and observation, without resort to supernatural theories; (2) data must be gathered in response to questions, and observations must be made to confirm or challenge hypotheses; (3) objective methods should be applied to eliminate any form of bias; (4) there should be consistency between observations and the original hypotheses within a given conceptual framework; (5) every hypothesis must undergo testing against competing hypotheses so that their problem-solving ability can be compared; (6) within the domain of a given science, generalizations ought to be universally accepted, and all peculiar occurrences must be explicable without recourse to supernatural factors; (7) a discovery or finding must be accepted only after repeated confirmation by independent investigators; and (8) science is characterized by the continuous refinement of theories through the replacement of incomplete or false ones and by resolving previously confusing problems (Mayr, 1997).

From these criteria, many would rightly conclude that biology should be treated as a genuine science alongside physics and chemistry. One question that still lingers, however, is whether biology is a provincial science that should not be placed on equal footing with the physical sciences. When the term "provincial science" first came into use, it was contrasted with "universal" in the sense that biology was concerned with localized and specific matter for which universal laws could not be imposed. It was argued that the laws of physics had no limitations of space or time and remained as valid in the Andromeda galaxy as on earth. Biology, by contrast, was considered provincial because all known forms of life have existed for only about 3.8 billion of the universe's approximately 10 billion years. Ronald Munson convincingly refuted this claim by demonstrating that none of the fundamental laws, principles, or theories of biology are explicitly or implicitly tied to a specific spatial or temporal region. The world of life has immense peculiarities, yet one can still generalize about unique phenomena. Although every ocean current has peculiar qualities, this does not preclude the establishment of theories and laws about ocean currents (Mayr, 1997).

We must question what "universal" really means before accepting arguments that deny biology the status of universality. Since non-living matter is believed to exist outside the earth, for any science dealing with non-living matter to be regarded as universal it must be applicable extra-terrestrially. Yet life has so far only been demonstrable on earth, while the laws and principles governing non-living objects are taken as universal simply because they have been validated on earth — the only place existence is presently known to occur. There is no justification for denying the term "universal" to a theory that holds true across the entire sphere within which it is applicable (Mayr, 1997).

The claim that biology is a provincial science rests on the idea that it is an offshoot of chemistry and physics and that, in the final analysis, its discoveries can be tied to physical and chemical theories. A proponent of biology's independence might counter that various characteristics of interest to biologists will never be reduced to physicochemical laws, and that many attributes of the physical world examined by physicists are irrelevant to the study of life. In this sense, both biology and physics are provincial. There is no justification for treating physics as superior simply because it was the first structured science. This historical accident does not confer upon it greater universality than its younger counterpart, biology. Until it is accepted that science contains different facets, its unity cannot be realized: there is physics, and there is also biology. It would be mistaken to reduce biology to scientific provinciality compared with physics — itself another provincial science (Mayr, 1997).

Nearly all advocates of the unity-of-science movement in the late nineteenth and early twentieth centuries were more philosophers than scientists, and they tended to overlook the diversity within the sciences. This diversity is pronounced even within the physical sciences, encompassing solid-state physics, elementary particle physics, classical mechanics, quantum physics, relativity theory, geophysics, oceanography, electromagnetism, and geology, among others. It grows exponentially when one considers the entire spectrum of the life sciences. Over the last seventy or so years, the futility of attempting to reduce all these domains to a single entity has been demonstrated repeatedly (Mayr, 1997).

Establishing the independence of biology has been a painfully slow process. It has required dismantling accepted concepts of physicalism such as determinism and essentialism, as well as certain metaphysical concepts proposed by biologists whose intuition points to biology as a separate entity but who still attribute to it metaphysical qualities like teleology or vitalism. Even today, opposition to biology's independence is often framed as a refutation of vitalism, as though vitalism were still a feature of the conceptual framework of contemporary biology (Mayr, 1998).

Conclusion

The foregoing explanations of the unique qualities of biology as a science demonstrate why moves to reduce biological theories to physics have not succeeded. Does this imply that science cannot achieve unity? Absolutely not. The implication is rather that such unity cannot be accomplished by reducing biology to physics. Any meaningful unification must proceed on a new and different basis.

Ernst Mayr advanced a formidable argument in support of the independence yet unified nature of the biological sciences. Comparing causality in physics and biology, he postulated that causality in biology was far removed from causality in classical mechanics. Having its own emergent properties, the structure of biology appears far more sophisticated. While mechanistic and materialistic theories could account for functional biology, other emergent properties — still within the boundaries of genuine science — justified evolutionary biology. The biology of ultimate causes (evolutionary biology) would therefore elevate biology, through the perspective of emergence, beyond complete reduction to the level of the physical sciences, and in doing so would provide the basis for unity within a unified biology. In making this argument, Mayr sought to establish a new philosophy of science grounded not in physics alone but in biology as well (Smocovitis, 1992).

In 1963, Mayr's elaborate reasoning about the two forms of biology was taken up by G.G. Simpson, who used it not only to oppose reduction to the physical sciences but to argue in favor of the central role of biology in achieving unity among the sciences. Writing for a broad audience, Simpson argued that biology was the science standing at the center of all sciences — the science most directly aimed at science's main goal and most definitive of that goal. It was within biology that the principles of all the sciences were embodied, and it was therefore there that science could truly attain unity (Smocovitis, 1992).

Simpson also advanced an important interpretive point: insisting that the study of organisms requires principles beyond those of the physical sciences does not imply a dualistic or vitalistic view of nature. Life is not thereby to be taken as necessarily nonmaterial or nonphysical. Rather, living things have been shaped over billions of years by historical processes, and the effects of those processes are systems that differ in kind from any inanimate system and are almost incomparably more complex. They are not for that reason any less physical or materialistic in nature. The point is that all known explanatory principles and material processes apply to organisms, while only a subset of the same applies to inanimate systems. Biology is therefore the science at the center of all sciences, and it is in that field — where the principles of all sciences are embodied — that science can indeed be unified (Mayr, 1998).

To restate the conclusion: there is no difference between physics, chemistry, and biology insofar as all are genuine sciences, yet as a science biology is not identical to chemistry or physics. It is an autonomous science, on equal standing with the equally autonomous physical sciences (Mayr, 1997). Unquestionably, the twentieth century was the era of biology, as demonstrated by its progress, its extensive research support — including practical applications in agriculture and medicine — and its growing importance for the future. One need only consider the intractable problems posed by exploding populations, environmental degradation, and the rise of infectious diseases to appreciate the prime role of biology in improving and sustaining human life. In the past century, no other science has been as instrumental in shaping human existence as biology, nor is any other likely to be in the immediate future (Bock, 1998).

References

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Mayr, E. (1996). The autonomy of biology: The position of biology among the sciences. The Quarterly Review of Biology, 71(1), 97–106.

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Mayr, E. (1998). Is biology an autonomous science?

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Smocovitis, V. B. (1992). Unifying biology: The evolutionary synthesis and evolutionary biology. Journal of the History of Biology, 25(1), 1–65.