Philosophy of Biology
Francisco Javier Navarro Prieto
If biology is the science that studies living beings, philosophy of biology is the branch of philosophy that examines its concepts, methods, and assumptions, as well as the implications that its results have for our understanding of reality. In a basic sense, it forms part of the philosophy of science: it analyzes how biologists explain, what kinds of entities they recognize, and what status their theories have. But its scope is broader. Biology is not only an object of philosophical analysis; it is also a source of ideas capable of transforming reflection on classical questions such as the nature of life, the mind, or the place of human beings in the world (Okasha, 2019; Godfrey-Smith, 2014). For this reason, philosophy of biology is at once a specialized branch of the philosophy of science and a form of philosophy informed by biology.
This double dimension helps to explain both its importance and its relative institutional novelty. The relationship between philosophy and biology is very old. In Aristotle, for example, the study of living beings and philosophical reflection form part of the same intellectual project: understanding the organization, functions, and principles of living things (Aristotle, 2019). For centuries, however, this relationship did not give rise to an autonomous discipline. Reflection on life remained dispersed across metaphysics, natural philosophy, and natural theology.
The major turning point was the publication in 1859 of On the Origin of Species by Charles Darwin. His theory introduced three fundamental ideas: that species change over time, that they share common ancestors, and that natural selection is the main mechanism of this change (Darwin, 1859; Okasha, 2019). These ideas transformed not only biology but also philosophy. First, they undermined the argument from design, which interpreted the complexity and apparent purposiveness of organisms as evidence of a creator (Paley, 1802). Darwin showed that this “design” can arise from a natural process without intention or purpose. Second, he placed human beings within nature, as the result of a continuous evolutionary process, challenging traditional views that regarded them as radically separate from the rest of living beings (Mayr, 1982). Third, he made biology an indispensable interlocutor for philosophy: many philosophical questions could no longer be formulated independently of scientific knowledge about life (see Darwinism and Social Darwinism).
Despite this, twentieth-century philosophy of science paid far more attention to physics than to biology. Logical positivism and other currents took the physical sciences as their model, characterized by general laws and well-defined mathematical structures (Kitcher, 1984). Biology seemed to fit poorly into this framework: its explanations are more historical, its generalizations less universal, and its categories more flexible. This tension contributed to the emergence, from the 1970s onwards, of philosophy of biology as an autonomous field, with authors such as David Hull, Michael Ruse, and Elliott Sober (Hull, 1974; Ruse, 1973; Sober, 1999). Although we now know that there was a richer prehistory —with earlier work on the philosophical problems of biology— it is at this point that the field became institutionalized (Grene and Depew, 2004; Nicholson and Gawne, 2015).
A useful way of characterizing philosophy of biology is to distinguish three types of inquiry. The first consists in applying general questions from the philosophy of science to biology: what counts as explanation, whether there are biological laws, or how different levels of description are related (Okasha, 2019). Biology has forced a revision of overly simplified models of science, highlighting the importance of mechanisms, historical contingency, and the autonomy of the special sciences. For example, many biological explanations do not take the form of universal laws comparable to those of physics, but instead reconstruct concrete mechanisms —such as the cellular processes involved in embryonic development— or historically unique sequences, such as the evolutionary origin of a particular adaptation. Likewise, phenomena such as natural selection or genetic drift depend on specific historical and population contexts, which has led philosophers to question the idea that all scientific explanation must ultimately be reducible to strictly universal laws.
The second type of work addresses conceptual problems internal to biology. Here the boundary with theoretical biology is blurred. Evolutionary theory has been a central focus: concepts such as natural selection, adaptation, function, or fitness have generated intense debates (Sober, 1999). So too have questions about the units of selection —whether selection acts on genes, organisms, or groups— and the problem of the species and its definition (Hull, 1974). In molecular and developmental biology, further issues arise concerning the concept of the gene, the idea of biological information, or the relationship between development and evolution (Godfrey-Smith, 2014).
The third type of inquiry uses biology to illuminate more general philosophical problems. In this case, biology is not only an object of analysis but also a conceptual tool. This occurs, for example, when evolutionary theory is used to understand the notion of function or to address questions about the mind, morality, or human nature (Okasha, 2019). This approach is part of a broader movement of “naturalizing” philosophy, which seeks to integrate scientific knowledge into philosophical reflection (Quine, 1969).
Among the characteristic problems of the field are the nature of biological explanation, the status of laws in biology, the concept of function, the notion of species, the interpretation of genetic information, and the relationship between evolution and development. Many of these debates combine empirical data, historical reconstruction, and conceptual analysis, and often involve direct interaction between philosophers and scientists (Godfrey-Smith, 2014). All this helps to explain the distinctive place of philosophy of biology. It does not merely correct the physicalist bias of traditional philosophy of science, but highlights the specificity of the life sciences: their historical character, their attention to variation, their use of functional explanations, and their focus on organized and complex organisms. For this reason, its problems connect easily with fundamental philosophical questions about identity, normativity, and apparent teleology. This is evident, for example, in the biological concept of function, which refers to the idea that certain traits exist “in order to” perform specific tasks, or in debates about biological normativity, that is, the possibility of speaking of organisms as healthy or defective, adaptive or maladaptive, without necessarily appealing to external or purely subjective criteria. Likewise, the apparent purposiveness of living beings —the fact that organs and behaviors seem directed toward ends— has forced philosophers to ask how complex functional organization can arise from natural processes devoid of conscious intention.
In sum, philosophy of biology is the space in which philosophical reflection and the life sciences meet in order to think about what organisms are, how we explain their traits, and what all this implies for our understanding of the world and of ourselves. If philosophy, as Wilfrid Sellars defined it, is concerned with understanding how things hang together in the broadest possible sense of both “things” and “hanging together,” then philosophical thought can hardly dispense with biology, that science which, at the very least, tells us who we are and where we come from.
Bibliography:
Aristóteles. (2019). Sobre el alma. Editorial CSIC. (Obra original publicada en c. 350 AEC).
Darwin, C. (1859). On the Origin of Species. John Murray.
Godfrey-Smith, P. (2014). Philosophy of Biology. Princeton University Press.
Grene, M. & Depew, D. (2004). The Philosophy of Biology: An Episodic History. Cambridge University Press.
Hull, D. L. (1974). Philosophy of Biological Science. Prentice-Hall.
Kitcher, P. (1984). 1953 and all that: A tale of two sciences. Philosophical Review, 93, 335–373.
Mayr, E. (1982). The Growth of Biological Thought. Harvard University Press.
Nicholson, D. J. & Gawne, R. (2015). Neither logical empiricism nor vitalism, but organicism. History and Philosophy of the Life Sciences, 37, 345–381.
Okasha, S. (2019). Philosophy of Biology. Oxford University Press.
Paley, W. (1802). Natural Theology. Early modern texts.
Quine, W. V. O. (1969). Ontological Relativity and Other Essays. Columbia University Press.
Ruse, M. (1973). The Philosophy of Biology. Hutchinson.
Sober, E. (1999). Philosophy of Biology. Westview Press.
Sterelny, K. & Griffiths, P. E. (1999). Sex and Death. University of Chicago Press.
Wimsatt, W. C. (1972). Teleology and the logical structure of function statements. Studies in History and Philosophy of Science, 3, 1–80.