At a conference on consciousness I went to recently, I suggested that bacteria are capable of care, but that rocks aren’t. Several people disagreed with me vehemently on this point. They said that it’s an obvious anthropomorphization to say that bacteria care. Their argument was that bacteria are just fully mechanical biochemical systems. To say a bacteria is capable of care is to speak metaphorically or something, but it can’t be literally true.
I don’t know about this. It seems to me true that bacteria are capable of caring but rocks aren’t. And you can’t just say bacteria are biochemical machines, because under the right description, so are humans. And moreover, seen through the lens of physics, humans are really no different from any other physical system, including rocks and bacteria. It’s all just fermions and bosons at the bottom anyway. So the argument that bacteria can’t care because they are mechanical or fully physical doesn’t work because under the right description humans look the same as bacteria and we all agree it’s appropriate to say humans care.
So the difference between the bacteria and the rock is not going to be a matter of being a physical system obeying physical law. Where I think the difference lies is in the way in which the bacteria’s physical matter is organized. It is at the level of organization that we see differences between rocks and bacteria. Bacteria, like all lifeforms, are balanced at the edge of thermodynamic disequilibrium. They are unstable in their organization, always ready to break down, but somehow they keep going (until death at least). Their unstability is characteristically stable, like a whirlpool in a river.
Moreover, there is something unique about the activities of the bacteria compared to other mechanical systems. The activities of the bacteria are continuously involved in producing the physical structures that constitute the bacteria. When the bacteria digests nutrients, it takes that matter and processes it in order to rebuild the membrane which distinguishes it from the environment. So the bacteria is continuously self-producing itself by always taking in nutrients to maintain the construction of the membrane which defines it against the environment. Theorists have called this kind of dynamic organization autopoietic. Whether or not autopoiesis alone is sufficient to define life against nonlife (some think you will need to also add notions of adaptivity), it is uncontroversial that organic lifeforms have a unique kind of organizational structure in virtue of something like autopoiesis.
But why should we think such an organizational structure warrants the claim that bacteria care about things? Well, I admit that such a gloss is taking advantage of metaphors to some extent, and all metaphors are in some sense literally false. But I still think it’s true to say bacteria care about things but rocks and other inorganic entities don’t. Imagine that you take some sugar and you place it in front of a rolling boulder or a moving bacteria. On one level of description, we could talk about the rock encountering the sugar in its pathway in input/output computational terms. The lump of sugar is an input into the system, the rock “computes” its response, and then generates an output, which is a slightly different change in behavior.
Similarly, we could use the same input/output description to talk about the bacteria encountering the lump. The sugar is an input into the system, the bacteria “computes” its response, and the output is a new set of behaviors. But just because we can apply this abstract characterization to both systems, that doesn’t mean that the rock and the bacteria are doing the same thing when they encounter the sugar. The difference, I think, is in the way the two entities “experience” the sugar. I don’t think the rock is really quite experiencing the sugar in the same way because I think the bacteria is on the look out for sugar. It is attuned for sugar, as opposed to other nutrients. It desires sugar. It seeks out sugar. It’s perception is valenced. It lives in a small lifeworld where all that matters is finding nutrients. None of this is true of the rock. If the rock sees the world through a valence at all, it valences everything equally. It has no preferences. No affectivity. As Heidegger said,
A stone never finds itself but is simply present-at-hand. A very primitive unicellular form of life, on the contrary, will already find itself, where this affectivity can be the greatest and darkest dullness, but for all that it is in its structure of being essentially distinct from merely being present-at-hand like a thing. (History of the Concept of Time, p. 255)
I think this is a very insightful remark from Heidegger. He recognizes that there is something unique about the organizational structure of a bacteria when compared to a rock. When I say a rock “cares” about the world, I am really referencing Heidegger’s technical notion of “affectivity”. I talked about this a lot in my Master’s Thesis. The key idea is about the bacteria “finding itself”. This kind of self-reflexive organizational structure is I think a nontechnical precursor to the concept of autopoiesis. Pretty speculative, but bear with me. The idea is that rocks and stones don’t see the world as ready-to-hand. That is, they don’t see the world in terms of what it affords the possibility of doing. In other words, it is appropriate to think of bacteria as organized with respect to the future. This is a potentially mystifying claim, but it’s not that complex. From the perspective of physics, it’s still all just fermions and bosons obeying the laws of physics. But when dealing with lifeforms, the concept of valence is necessarily tied into the concept of a creature lacking something. The bacteria lacks the nutrients necessary to construct its membrane, so it seeks it out. Lack in organisms is always defined with respect to the future, what some ecological psychogists have called prospectivity. This type of absential, future-oriented organization is what Terrence Deacon has called ententional phenomena in his new book Incomplete Nature. I haven’t finished the book yet, but what I have read so far is quite brilliant.