About

Enacting Life grew out of an interest in different ways of thinking about the mind. In psychology and neuroscience, perceiving and knowing are commonly understood in terms of a brain processing information about a world whose features are already specified. Enactivism offers a different starting point: it asks how cognition arises through the activity of a living being.

As described at peterjmarshall.com, my background is in developmental psychology and neuroscience, although my undergraduate training was in zoology. I became interested in ideas around enactivism and embodiment in part because they raised questions about assumptions I had become accustomed to working with. But following those questions took me into philosophical literature that my training had done relatively little to prepare me for. I began writing the documents in Enacting Life as a way of working through that literature for myself, and I hope that in the longer term they will be useful to others.

Psychology studies what people and other animals do, but it has also always tried to understand the mind. Psychologists have studied behavior, constructed models of mental processes, and investigated the neural mechanisms underlying thought and experience. These approaches have taught us a great deal, but they leave open a more basic question: what is the mind, and how does it belong to a living being? Wherever we look for an answer, the mind seems to slip from view.

Part of the difficulty may lie in a division inherited from Descartes. For Aristotle, the soul was the form or organization of a living body, not a separate thing inhabiting it. Plants, animals, and people all had souls in this sense, differing in the capacities their organization made possible, from nourishment and growth to perception and movement to reasoning. Life and mind were parts of one continuous account. In the seventeenth century, Descartes broke this continuity. He explained the bodies of animals and humans as machines, working through the arrangement and motion of their parts, and treated the mind as a distinct thinking substance found only in humans. The mechanical approach proved enormously productive, and it became the model for explaining living bodies. But it left the mind standing apart from life, and psychology inherited that division when it set out to study the mind scientifically. I wonder whether what slips from view is not so much the mind as the living being whose mind we are trying to understand.

Language models make all this harder to think through. They can produce language and carry out tasks without being alive, which raises the question of what such abilities tell us about minds. I return to this in the Coda. These readings do not attempt to resolve the problem of mind, and readers may reach the end without a clear answer to what the mind is. Instead, they take a narrower route, asking how the organization and activity of a living being make it possible for things to matter to it. This seemed to me a place where it might be possible to make some progress.

What draws me to enactivism is that it offers a way of grounding psychology and neuroscience more coherently in biology, beginning with what being alive involves. It asks how things come to have significance for a living being, rather than taking their meaning as already given. For me, this opens up questions that are easy to overlook when cognition is understood primarily as information processing. My interest is not confined to psychology and neuroscience, though. Starting from what being alive involves also lets us understand human lives within the wider context of living things, as one way of being alive among many.

In Embodiment and Human Development (2016), I worried that the individual could disappear into descriptions of organism–environment coupling. In The Shared Origins of Embodiment and Development (Marshall et al., 2021), we drew on Willis Overton’s account of embodiment as a bridge between bodily form, engagement with the world, and lived experience. I still find that framework useful. But I want to bring the living individual more clearly into view: what it is capable of doing, what it actually does, and how things can matter to it. I have tried to bring that emphasis to these readings, and it is also why I distinguish the significance of an encounter for an organism from the harder question of what the encounter feels like to that organism.

The readings follow the account of living organization that developed from Humberto Maturana and Francisco Varela’s work, and ask what follows from it for understanding cognition. That goes further than saying that having a body influences how we think, which is why I rarely use the term “embodied cognition” in these readings or elsewhere.

Enactivism is not a set of findings to add to psychology and neuroscience. It is closer to a different way of framing what those fields are trying to explain, and its value depends on whether that framing changes which questions get asked and what counts as an answer. The readings take positions, but they do not try to settle the debates within enactivism or show how to apply it. They are meant as a way into these questions, and into what they look like from psychology and neuroscience. Where they lead is for the reader to work out.

Enacting Life is a companion to About Development, which asks how organized living beings and their capacities develop. The two resources approach overlapping questions from different starting points, and each can be read on its own. Both connect to my article “Psychology in 2125” in Perspectives on Psychological Science; see the background and commentary at peterjmarshall.com.

How the Readings Were Made

I began developing Enacting Life in 2022. I wrote in Google Docs and embedded the documents on a Google Site. Knowing that the readings were publicly available, even without much of an audience, encouraged me to make the explanations as clear as I could. But the readings were initially as much for my own benefit as anyone else’s.

Over time, I wanted to bring the material together into a freely available educational resource that would offer others a way into some difficult ideas and explain why they might matter for the science of the mind. In 2026, I moved the readings to GitHub Pages using Quarto, making them easier to read and navigate.

I should be clear about what kind of resource this is. I am a psychologist and neuroscientist, not a philosopher, and I did not set out to read everything written about enactivism and produce a comprehensive treatment of it. That would have taken years, and it was never going to happen alongside my other work. Instead, I took parts of the literature and tried to develop my own understanding of them, and my early versions of these readings were not very good. The revisions described in the note on AI use below made them clearer and more accurate, but they also risk making the readings sound more assured than my understanding of every part of them. What I hope they offer is a way into these ideas from psychology and neuroscience, put together by someone who has had to make that journey himself.

It has never been entirely clear to me who this resource is for, but I kept working on it because I am drawn to the ideas at the center of enactivism. Making these readings freely available is a way of sharing that ongoing effort. I hope they will be useful to others who find themselves asking similar questions, and I welcome corrections and disagreements.

A Note on AI Use

In summer and fall 2026, as I moved these readings to GitHub Pages, I worked on revising them with the assistance of AI tools, specifically Claude and ChatGPT. The tools helped me compare arguments across the individual documents and find clearer ways of putting things, and they suggested further connections for me to consider. Although the original drafts were mine, the final product was the result of a lot of back and forth with AI tools. The resulting resource is, I think, more coherent and accessible than it was before.

But there is a tension in using AI in this way. One of the ideas running through Enacting Life is that meaning is not in the marks on a page. The writing on which these systems were trained was produced through human activities in which words meant things to people. The systems can work with patterns in that writing without sharing the activities that gave it significance. Yet I used these systems to help me explain precisely that point. The Coda considers this issue more generally; here it matters because of how the readings themselves were made.

In reflecting on all of this, I have asked whether working with these tools has helped me understand the ideas better. In one respect I think it has. The enactivist perspective is not one uniform thing. It is sprawling and diverse, with different historical strands and interpretations, and the tools could lay those strands out at length without having to choose among them. Although Enacting Life is meant as an introduction to enactivist ideas, it would not be enough simply to list the different perspectives and say: here they are, make of them what you will.

Maturana’s remark that “anything said is said by an observer” (Maturana, 1970/1980, p. 8) applies here. Any account of enactivism, even one that presents itself as a neutral survey, consists of distinctions that someone has drawn. On Maturana’s account, AI systems are not observers in this sense. They could suggest distinctions and connections, but they could not determine which ones mattered for the account I was trying to give. That was for me to work out: what to include, what to leave out, and where to stop, given the limits of my understanding. Working with the tools made that clearer to me. I could probably give a lecture on enactivism without notes. It would not be a great lecture, but I hope someone new to these ideas would come away understanding more. That is what I have tried to do here.

The usefulness of AI tools does not resolve questions about the human intellectual work on which they depend and how that work was obtained, or about the interests that guide their development. I remain conflicted about these tools, even as I came to rely on them for finalizing this resource, and I am writing about these questions elsewhere. I take responsibility for what appears in these readings, while recognizing that the process of producing them involved more than my own unaided writing.

References

Marshall, P. J. (2016). Embodiment and human development. Child Development Perspectives, 10(4), 245–250. https://doi.org/10.1111/cdep.12190

Marshall, P. J., Houser, T. M., & Weiss, S. M. (2021). The shared origins of embodiment and development. Frontiers in Systems Neuroscience, 15, 726403. https://doi.org/10.3389/fnsys.2021.726403

Maturana, H. R. (1980). Biology of cognition. In H. R. Maturana & F. J. Varela, Autopoiesis and cognition: The realization of the living (pp. 5–58). D. Reidel. (Original work published 1970)