The Scale of Knowledge
Friday 28 June 2024
Human knowledge, I have urged in several recent newsletters, must be understood as a human construction, and several important consequences follow from this. One of these consequences that I haven’t yet discussed in detail is that human knowledge represents what we may call mesophilic norms. Mesophilic (“middle loving”) has been introduced as a contrary to extremophilic (“extreme loving”). In biological terms, we judge biological extremophiles as being extreme in how far they diverge from the mesophilic norms of human beings. We occupy the Golden Mean of biology, finding ourselves, like baby bear’s porridge and chair and bed, in the comfortable center, located between uncomfortable extremes. Organisms that can live at very high or very low temperatures, or at very high or very low pressures, are extremophiles, and in every case we occupy the center from which Copernicus supposedly banished us. The Ptolemaic conception of the world dies hard. Like dead Cthulhu dreaming, waiting for the proper moment for the Old Ones to return, it seems like the geocentric and anthropocentric conceptions of the world were dreaming in a state not truly dead, and not truly alive.
Like our preferred norms of temperature, air pressure, oxygen concentration, salinity, and nutrients, our knowledge is clustered around mesophilic norms. Scale is an elusive symmetry (although we do find symmetry across scales with fractals). The results of most scientific experiments can be replicated if you move the experiment to another place (translation in space) or if you conduct the experiment at another time (translation in time), but many experiments will fail is you transpose them in scale. What works at a human scale may not work an order of magnitude larger or an order of magnitude smaller. Atoms, molecules, cells, and biospheres need to exist at a certain scale in order to function as the kind of beings that they are. Of course, there is some wiggle room. We don’t know how large or how small a biosphere could be, but my guess is that there are lower limits below which a biosphere would fail, or upper limits above which a biosphere would fail. Part of this would be due to the interaction of a biosphere with gravity. Of course, there may be qualitatively different biospheres that correspond to the gravity of different planets.
René Heller’s useful conception of a “superhabitable world” — worlds with “more benign environments to life than Earth” — imagines a planet with a richer biosphere than Earth. Obviously, “richer biosphere” is ambiguous, so we would need to establish some metrics to differentiate, say, more or less biomass, greater or lesser biodiversity, and so on. In his paper “Better than Earth” Heller suggests that a superhabitable world would be a “superearth” with higher gravity:
“Higher surface gravity would tend to give a middling super-Earth planet a slightly more substantial atmosphere than Earth’s, and its mountains would erode at a faster rate. In other words, such a planet would have relatively thicker air and a flatter surface. If oceans were present, the flattened planetary landscape could cause the water to pool in large numbers of shallow seas dotted with island chains rather than in great abyssal basins broken up by a few very large continents. Just as biodiversity in Earth’s oceans is richest in shallow waters near coastlines, such an “archipelago world” might be enormously advantageous to life. Evolution might also proceed more quickly in isolated island ecosystems, potentially boosting biodiversity.”
I have a vague recollection (which could be mistaken) of reading a Heller paper in which he argued that a planet with higher gravity would have a denser atmosphere than Earth’s, and this would mean a greater proportion of the biomass would be airborne. Obviously, this has limitations. He also writes in “Better than Earth”:
“Earth also has a life-friendly size: big enough to hold on to a substantial atmosphere with its gravitational field but small enough to ensure gravity does not pull a smothering, opaque shroud of gas over the planet.”
And while an atmosphere of greater density could support flying and floating life forms, if the gravity is heavy enough it not only pulls down a shroud of gas, it would also pull down flying and floating organisms. As I said earlier, different gravitational constants might correspond to qualitatively distinct kinds of biospheres. And indeed a planet might be superhabitable in more than one sense, given that we could measure biospheric productivity in different ways, each of these measures would correspond to distinct optimal conditions: the planet with the greatest biomass, the planet with the greatest biodiversity, the planet with the greatest ability to adapt to changing conditions, and so on. Given that our only knowledge of life is life on Earth, Earth is optimal across all these categories, but this may not always be the case.
Biospheres on planets with lower gravity would also pose problems. Laboratory studies suggest that trees could not grow on the Moon, but they could grow on Mars — this is strictly about the gravity, not light or soil conditions, etc. Lunar gravity is insufficient for trees to grow normally, but there are other plants that likely would grow. Different gravitational constants would be highly selective for the resultant biosphere. If we someday were to terraform the moon, there might be grasslands, but no forests. A terraformed Mars, on the other hand, might be able to grow forests in addition to grasslands. But at some point, with a planet too small, or a planet too large, a biosphere would fail.
Only a single biosphere is known to us, so we can’t at present have the kind of knowledge about biospheres that we have about atoms, molecules, and cells. And while these objects of knowledge are several orders of magnitude removed from the scale of a macroscopic human being, we have good enough instruments to study them, and a sufficient number of examples that we have knowledge of a reasonable degree of exactitude about them. But beyond subatomic particles, things tend to get pretty fuzzy. And at the largest scales of the universe, our knowledge is also rather fuzzy. There is a certain consensus on particle physics and cosmology, but these sciences are much more open to revision than, say, cell biology. When some early observations of the James Webb Space Telescope suggested that the universe may be older than we have supposed since the big bang model came to maturity over the course of the twentieth century, there was a readiness to consider this possibility, and we may someday, with cosmology, reach the point that we have reached in regard to the microscopic world: once we have enough large telescopes in space, and enough telescopes of different kinds (sensitive to the entire EM spectrum), we may have good enough instruments to study the cosmos, and a sufficient number of examples well known to us, that we possess knowledge of a reasonable degree of exactitude.
Not long ago I skimmed a paper (of which I have since lost track, and I have not been able to find it again despite my attempts) that argued that our observations of the expansion of the universe may be an artifact of our position in the universe that is not representative of the universe on the whole. That is to say, the paper was arguing that cosmology since Hubble might be mistaken because we happen to occupy a place in the universe at which observations give the appearance of expansion. And from the origins of Hubble’s cosmology up to 1998 it was simply assumed that expansion was slowing down, and the important question was the rate of the deceleration. Since 1998 it has been accepted that the expansion of the universe is accelerating, and we have no way to explain this so we invoke the cipher of “dark energy.” This is the extent to which large scale cosmology is still up for grabs: contemporary science could be consistent with any of several large scale models that are mutually exclusive. We may favor one at the present time, but new observations could change this and force us to reconsider the past century of apparently rapid growth in the knowledge of cosmology.
Suppose that we do expand our suite of telescopic instruments and achieve knowledge of the universe that I have above called knowledge of a reasonable degree of exactitude. We are then faced with the hard limits of the observable universe. If our universe exists in some greater context, our knowledge of the context in which our universe plays out its natural history is at present non-existent, and wholly new technologies and techniques of research would be needed to study this scale of magnitude that lies beyond the size of the visible universe. The only property that we could today ascribe to the scale of magnitude under which our universe is subsumed as one universe among many, is that this context is consistent with the existence of our universe. But there are many ways that this could be true, and some of these ways would tell us very little about the nature of what lies beyond the universe. Imagine, for example, that our universe is like a form of pathology, like a cancerous growth, and so it is walled off and compartmentalized by the larger structure so as to minimize the danger to the whole. Here the existence of our universe would be consistent with its context, but not because it is like other universes, one among many, but because it is unlike other universes, i.e., it is unrepresentative of the larger context on the whole.
Human knowledge represents epistemic mesophilic norms. Some of our knowledge may scale to lesser or greater orders of magnitude, but it is likely that some of our knowledge will not scale. Beyond the scales to which our epistemic mesophilic norms apply, the universe is unknown to us. We need not even assert that the scales of the world that lie beyond science-as-we-know-it are unknowable, only that the concepts that human beings have formed may not be applicable to scales of magnitude a sufficient distance from human mesophilic norms, i.e., we need not assert that that which is unknown to science-as-we-know-it is intrinsically unknowable, only that it is unknown to date. This is both hopeful and humbling. It is humbling in the way that the Copernican principle is humbling, but it isn’t merely an alternative formulation of the Copernican principle. As I discussed above, our mesophilic centrality is an inversion of the Copernican principle. But this is at the same time hopeful. The more we explore the universe, and when we eventually encounter something dramatically different from ourselves and the evolutionary process that produced us, the more we will be able to put ourselves and what we represent in context. Only then will we know if we are representative of the universe on the whole, or if we are a cosmological outlier. And this effort would be part of the hopeful project of extending our knowledge beyond mesophilic epistemic norms, eventually arriving at what we could call extremophilic knowledge, and an extremophilic epistemology, which is a project larger than humanity itself, but a project to which humanity could conceivably contribute.
Near the beginning of The Decline of the West, Oswald Spengler wrote, “We men of the Western Culture are, with our historical sense, an exception and not a rule. World-history is our world picture and not all mankind’s.” (p. 15) This could be taken in a parochial sense, and I doubt this observation would be welcome today, but this is a view upon which I have been slowly converging for years, and it has cosmological implications as well. If we expand into the universe and explore as I have suggested in the previous paragraph, extending our knowledge beyond its natural limits until it becomes extremophilic knowledge, it will still be human knowledge. Our account of the universe will still be a human account of the universe, just as when Westerners write the histories of other peoples, even writing the histories of peoples, reconstructed from archaeological evidence, who did not write their own history, it is still a Western history of these peoples. The more we embrace this unavoidable fact, rather than struggle against it (which would be to struggle against ourselves), the better the result will be, the more our knowledge will expand, and the more we can contribute even to a project larger than humanity itself.
