This anthology heralds a revolution in the philosophy of biology, arguing that the long-standing dominance of the mechanistic framework should finally come to an end. Ambitious and innovative, yet cogent and empirically grounded, Daniel J. Nicholson and John Dupré’s Everything Flows is a must read for anyone interested in understanding new directions in the investigation of the biological world. While they come from different perspectives, the authors in the volume represent a robust community of philosophers and scientists who take seriously the idea that the world is not made up of particles or things but rather processes.

Everything Flows is divided into four sections that represent the main themes well: “Metaphysics,” “Organisms,” “Development and Evolution,” and “Implications and Applications.” Articles in the “Metaphysics” section discuss mainly traditional issues such as persistence and causation. Articles in the “Organisms” section take up issues surrounding what it means to be an organism, perhaps the timeliest of which are several contributions discussing the nature of biological individuality. The “Development and Evolution” section includes articles on a variety of areas of scientific and philosophical research (ranging from developmental systems theory and modeling strategies, to evolutionary theory and reductionism). Finally, articles in the “Implications and Applications” section connect process ontology to an even wider range of scientific and philosophical issues, including cancer, olfaction, personal identity, and macromolecular biology.

For those looking for a concise definition of “process ontology” and what this project is all about, look no further than the first paper: Dupré and Nicholson’s “Manifesto.” In this piece, which serves as the framing chapter for the entire anthology, Dupré and Nicholson lay out what they consider to be the primary tenets of their new paradigm: “the living world is a hierarchy of processes, stabilized and actively maintained at different time scales” (3). In philosophy, process has traditionally been associated with Whitehead, but Dupré and Nicholson distance themselves from this tradition, instead identifying C. H. Waddington as the relevant historical antecedent for their work. Waddington was a developmental biologist and geneticist whose focus on biological phenomena aligns closely with the work of the authors in this volume.

Dupré and Nicholson highlight the empirical motivations for thinking that the living world is made of processes: metabolic turnover, life cycles, and ecological interdependence. First, they stress that organisms are open systems, which must continually exchange energy and matter with their environment in order to maintain their far-from-equilibrium states. They contend that this reality forces us to recognize that organisms are “metabolic streams of matter and energy” rather than fixed or solid objects (17). The next empirical motivation they cite is that biological entities do not have fixed characteristics but rather undergo a series of changes in physiology and behavior over the course of their lifetimes. This again supports a processual rather than static conception of biological entities. Finally, they point out that ecological communities are deeply entangled such that determining the boundaries of a biological individual, or even determining how many individuals are present, can become quite challenging. They believe that understanding ecological relations as intertwined processes best enables us to understand biological individuality. This view of the world has a wide range of philosophical and scientific consequences: process ontology can ground critiques of essentialism, reductionism, and mechanism, and it can call into question traditional views in physiology, genetics, evolution, and medicine (e.g., considering cancer a process as opposed to a set of somatic mutations). By covering a large territory, their manifesto introduces the primary tenets and potential implications of this processual revolution in biology.

Two of the most compelling entries in the volume address the puzzle of biological individuality. They are “Symbiosis, Transient Biological Individuality, and Evolutionary Processes” by Frédéric Bouchard and “From Organizations of Processes to Organisms and Other Biological Individuals” by Argyris Arnellos. Bouchard argues that biological individuals are defined by the processes they participate in, or in other words, that functions define individuals. Contrary to what some might expect, Bouchard does not take this to mean that individuals are unreal or merely apparent. Rather, he argues that this account of individuality is necessary for an understanding of evolution. In a slightly different but related account, Arnellos argues that functional concepts of individuals will give us, at best, a hazy picture. Arnellos proposes a process-based organizational account of biological individuality that defines individuals as self-maintaining processes organized such that their constitutive and interactive aspects are coordinated. While Bouchard and Arnellos both offer processual accounts of biological individuality, Arnellos adds systemic organizational criteria beyond the functional criteria of Bouchard. These, and other articles in the anthology, offer novel perspectives that advance the ongoing conversation about biological individuality.

While much of the biological sciences treat development as an aberrant phase, processual thinking brings development front and center. Many of the examples used in this anthology come from various stages of biological development. For example, Rani Lill Anjm and Stephen Mumford argue that their dispositional account of causation better accommodates the dynamism of biology, including that of pregnancy specifically. Paul Griffiths and Karola Stotz argue that Developmental Systems Theory (DST) is best understood as a type of process theory because it seeks to explain developmental outcomes “as the result of dynamic processes in which some of the interacting factors are products of earlier stages of the process, rather than as the result of the arrangement of preexisting factors into a static mechanism” (229). They point out that the two key concepts of DST, epigenesis and developmental dynamics, are both inherently processual. Laura Nuño de la Rosa argues that the lack of dynamic imaging techniques has caused scientists to abstract from the processual nature of development, traditionally depicting and studying development as a series of static stages. What these (and other) contributions highlight is the natural affinity between a processual philosophical framework and developmental biology. While developmental biology is scientifically a small portion of biology as a whole, development itself could be said to be the ultimate process of life on earth—all living things are constantly engaged in developmental processes. This connection between processual thought and development is taken to be one of the key empirical supports for process ontology.

The temporal aspects of process are strikingly underrepresented in this anthology. Not only do processes unfold in time, but processes are fundamentally entangled with time. If we understand biological entities as processes rather than things, temporal extension is seen as part of the entity, rather than as an external independent variable. Most of the authors in this anthology explicitly recognize a process as both spatially and temporally extended, yet the focus of the articles in this volume is primarily on spatial complexities. One exception to this is Laura Nuño de la Rosa’s article, “Capturing Processes: The Interplay of Modelling Strategies and Conceptual Understanding in Developmental Biology,” which addresses some of the ways temporality is modeled in the biological sciences. De la Rosa argues that imaging strategies that incorporate time will allow scientists to put temporality back into the biological world and, thus, recognize the processual nature of biological entities. However, abstractions from temporality seem to mark biological research in far more areas than just imaging techniques. On the one hand, biologists tend to make physical or procedural manipulations in order to slow down the timescales of biological systems moving more rapidly than our timescale (e.g., putting bacterial cultures on ice or measuring at moments rather than through time). On the other hand, biologists tend to use mathematical extrapolation to artificially speed up systems that are moving more slowly than ourselves (e.g., using mathematical models to investigate evolutionary processes). These manipulations of time by biologists do not seem to be haphazard but rather are systematic in nature. How biologists abstract from temporal dynamics, the implications of these abstractions, and how different temporal scales play a role in biology similar or dissimilar to different spatial scales is not adequately addressed. Although neglected in the volume, the processual revolution opens up a new way of investigating time in biology, and it will likely spur more fruitful work on the topic.

One final concern is Dupré and Nicholson’s choice of label. They call the views represented in the volume ‘process ontology’, but it might be better known by another name. While all of the authors in the volume are committed to taking process seriously in some way, not all of them see it as a project in ontology. Instead many authors take an entirely agnostic or pragmatic stance on the metaphysical matters. Dupré and Nicholson are aware of this conceptual controversy within the processual community but defend their choice to make this an explicitly metaphysical project by suggesting there is not much different between these choices given a certain kind of naturalism. However, it strikes me that perhaps a more neutral name for the general project would be processualism or the process framework. After all, this project aims to bring to the fore a novel frontier for philosophers of biology; a label that unduly restricts these prospects will not adequately serve this revolutionary project.