Fuzzy individuals


Nature Alive

I have an interest with the philosophy of biology, but I’m a dilettante. My background is in evolutionary biology; I haven’t had a philosophy class since I was an undergrad at UCF. Nevertheless, if you study the so-called Major Transitions, you’re inevitably going to end up reading some philosophy. Topics such as multilevel selection, emergence, and the nature of biological individuality come up over and over again in this field, and philosophers of biology have made important contributions in all of them.

Among these, I find discussions of the nature of biological individuality fascinating, and I’ve written about it often here. Volvox and its relatives often come up in these discussions, and they have for a long time. A new edited volume, Nature Alive, continues this trend in a chapter by Lukasz Lamza (“Cells, organisms, colonies, communities–the fuzziness of individuality in modern biology”).

The whole book is set up within the framework of Alfred North Whitehead’s “process philosophy,” something I’m entirely unfamiliar with (a limitation of being a dilettante). I found it to be so full of jargon that I can’t reliably judge whether Whitehead’s view, and the chapters it has influenced, represent a useful way of looking at biology or mystical nonsense. The book is full of apparently approving references to holism, teleology, and postmodernism and of critiques of reductionism, neo-Darwinism, and materialism. These aren’t necessarily bad things (but teleology, really?), but taken as a whole they seem like red flags to me. I’d need to dive much deeper than I intend to, at least today, to feel halfway qualified to judge.

Rather, I want to focus on something closer to my wheelhouse, Lukasz Lamza’s chapter and what it has to say about Volvox. The main point of Lamza’s essay is that

…the assumption of organismic individuality and independence in biology is becoming increasingly fuzzy and cumbersome in the face of our growing knowledge of the natural world. The well-known “formal,” structural criteria that are used in biological sciences in order to distinguish, for instance, colonies of unicellular organisms from multicellular organisms are breaking down.

I would argue (have argued) that they have broken down. This is well-traveled territory. None of the “traditional” criteria for defining individuals (contiguity, indivisibility, physiological discreteness, genetic uniqueness and homogeneity, integration, differentiation, etc.) “work,” that is, they either aren’t universally applicable, don’t unambiguously identify individuals, or don’t match our intuitions or the normal meaning of the word “individual.” I thought this was original when John Pepper and I said it, but as a grad student I had no grasp of how much had already been written on the topic.

Lamza presents a “selection of biological facts” in support of the fuzziness of individuality, among them

…numerous groups of protists, traditionally classified as unicellular, or at best, colonial, should in fact be understood as multicellular,

…even prokaryotic organisms organize themselves in complex colonies to the degree that cyanobacteria are sometimes called a multicellular group of bacteria,

…there is full overlap in labor division and cellular complexity–one of the traditional hallmarks of multicellularity–between all domains of life, including bacteria, protists, plants, fungi, and animals,

and

…even typically unicellular organisms (e.g., solitary predators such as certain ciliates) do not live in a biological vacuum, but come into contact with innumerable other cells, both of their own species as well as of other species, and they communicate with them in numerous ways, ranging from chemical, through genetic, to biochemical modes.

I think there are better reasons to reject the traditional criteria for individuality, but I agree with the overall conclusion. The traditional criteria all have their failings, which is why the field has long since moved to criteria based on evolutionary theory, none of which are mentioned in this chapter.

The next subsection or so seems to go off the rails, touching on panpsychism (it’s not clear to me if the author endorses this idea or merely attributes it to Whitehead) and discussing Whitehead’s position that “a single atom can be seen as a society.” The latter point appears to rely on a far-from-standard definition of “society,” which seems like a useless exercise to me (akin to defining life as anything that moves and then declaring that windmills are alive). Again, though, dilettante. Criticizing complex concepts that I’ve only heard about second-hand would be foolish. I will say that from Lamza’s description, Whitehead’s ideas seem pretty kooky.

Volvox first appears in the section entitled “The Concept of ‘Living Person’ as a Candidate for ‘Independent Individual’.” As with “society,” Whitehead’s definition of “living person’ seems to have been far from standard. I say “seems to have been” because there is some dense philosophese here. See if you can make more sense of this than I can:

To appreciate the difference between societies [remember, societies include atoms] and living persons, one must explore Whitehead’s theory of prehensions. In short, a becoming actual entity prehends, or “feels,” not only other, past actual entities (which may be seen as the metaphysical basis for causality wherein one entity becomes part of another entity’s formation process), but also eternal objects (i.e., “pure possibilities”), which introduces novelty into the process. Here, one may speak of physical prehensions (prehensions of other actual entities) and conceptual prehensions (prehensions of eternal objects).

As best I can make out, being a living person has something to do with memory and learning:

One thing that is especially striking when reading about living persons is the fact that the stability is achieved through the intervention of novel eternal objects, which translates roughly to elasticity of behavior or, possibly, memory.

I’m still lost. if any Whiteheadians are reading this and can clarify, I’d be appreciative. At any rate, Lamza thinks that the concept of a living person can help us understand Volvox. Or maybe that Volvox can help us understand the concept of a living person:

Here, in the context of studying the notion of “an individual” in the biological description of cell associations, colonies, ecosystems, etc…., it is especially interesting to see how Whitehead’s notion of a “living person” might help. Accepting for the sake of the argument that a single-celled organism is a living person sensu Whitehead, a casual, random meeting of two such unicellular organisms, such as that which occurs when two free-living amoebae brush agains each other for an instant, is not a living person. In this temporary union there is no element of common form transmitted across moments of time, let alone an aggregation of novel forms of potentiality that would give it a broad “toolkit” of possible reactions. A colony, however, may exhibit these properties. The cells of Volvox, for instance, clearly are joined by a certain common element of form. This is what enables morphogenesis and in this case, the characteristic turning “inside-out” of the spherical colony by the concentrated contraction of fibers lining the sphere. This would not be possible if every cell did not participate with reference to the same set of eternal objects, to use Whitehead’s term. The contraction of the fibers lining each cell occurs, because the colony in the form A can take the form B (which is turned inside-out with regard to form A). Also, this can happen in a number of ways. So one might say that the process of inversion is teleological–or to put it in less controversial terms–goal-oriented. It is worth noting that Volvox is one of the organisms that is suspected to be capable of epigenetic learning, and even “anticipation,” by some biological theorists.

There’s an endnote associated with the last sentence, and I had to run it down, since evidence of learning in Volvox would be news to me. The endnote reads “For example, see Simona Ginsburg and Eva Jablonka, “Epigenetic Learning in Non-Neural Organisms,” Journal of Biosciences 34.4 (2009), 642.” Here’s the totality of what Ginsburg and Jablonka had to say about Volvox:

Plants (especially those able to move), fungi, sponges (especially their motile larvae), slime moulds, and possibly also Trichoplax (a primitive non-neural multicellular creature that crawls on the ocean floor) and Volvox (motile multicellular algae) are all likely to anticipate and learn. However, the evidence for learning in non-neural multicellular organisms is scant, and it seems that few relevant experiments have been done to investigate this issue. We found no evidence for learning in Volvox, although there is a possibility of memory, since the phototactic threshold (the minimum light intensity required to get any phototactic response) was reported to rise by more than three orders of magnitude after spheroids that had been kept in the dark for a few hours were exposed to direct sunlight for a few moments (Kirk 1998).

and later

The few cases of actual and possible learning that we have surveyed are all different and for many of them the underlying biochemical mechanisms are unclear. We know of no evidence for mechanisms like those illustrated in our toys models, but we predict that such mechanisms exist and underlie different types of non-neural learning in unicellular and multicellular organisms. We suggest that unicellular organisms, especially actively moving protists, and nonneural organisms with the ability to adaptively and rapidly alter their location and morphology (for example, Volvox, sponge larvae and “sensitive” plants) may be good candidates for such study.

So the bottom line is that Ginsburg and Jablonka speculated that Volvox could be capable of learning, but could find no evidence to that effect. Going back to Lamza, the argument that inversion is teleological seems to be

The contraction of the fibers lining each cell occurs, because the colony in the form A can take the form B…

I don’t see how inversion happens “because the colony in the form A can take the form B.” I could as easily say inversion happens because the cells move relative to the cytoplasmic bridges, or because the colony has sufficient ATP to drive the motor proteins that cause those movements, or because it got enough sunlight to produce that ATP, or because it has an intact copy of the invA gene, or because it inherited that gene from its undifferentiated ancestors…

Although they’re all true, none of those facts suggest teleology to me. It’s true that the colony in the form A can take the form B, but by what logic is that potential conclusively the cause of inversion? Even if it is, how does that lead to the conclusion that inversion is goal-oriented? Maybe I need to read Whitehead to understand.

Lamza returns to Volvox in the conclusion:

As I tried to show, Whitehead’s general metaphysical term of “living persons” seems to fulfill our expectations of what a biological individual should be. I hinted that recent research in biology leads to the need to include superorganisms (main organisms and microflora), certain colonial organisms (Volvox), bacterial biofilms, and possibly even whole biotopes, in this group.

If I understood what Whitehead meant by “living persons,” I’d be much better able to evaluate this. I wasn’t able to find a clear definition in this essay.

I’d be really interested to hear what some real philosophers think about this. Is my ignorance of Whitehead’s writings a crucial gap in my education? Would all of this make sense if only I had the background to understand it? Is Whitehead considered an important thinker or a fringe character? Are his ideas of panpsychism and teleology as kooky as they sound to me?

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