Work in Progress: On the Trail of Universal Biology

NoRCEL took the trouble to contact me a couple of times to ask if I am interested in participating in the conference this summer. I’ve pulled back somewhat from this kind of activity, but, as I said, they actually reached out to me, so I have been seriously thinking about it. I have been casting about for an appropriate topic since I participated in their last online event with my presentation, “How many branches are there on the tree of life?” This presentation was essentially an extension of my 2019 Milan presentation, “Peer Complexity during the Stelliferous Era.” I met Sohan Jheeta of NoRCEL at that Milan conference, and he had invited me to an in-person conference that didn’t happen, and which was eventually replaced by an online event. I was disappointed by missing a chance to given an invited keynote at the University of St. Andrews, but that moment has, shall we say, passed, and I don’t want to repeat myself, even if I continue to develop the same themes.

NoRCEL has been working on a “gap map” that seeks to show where the gaps are in origins of life research, and as part of the gap map, Martin Dominik of NoRCEL has asked whether a “universal biology” is possible. With this in mind, I had a title for a presentation, “Universal Biology: Can We Formulate a New Big Picture Science?” and this is something I would definitely be interested in talking about, since I often mention the lack of big picture sciences, but I didn’t make much progress with this idea. Also, the way I would come at this idea would be a bit out of the mainstream. The idea of a universal science, or a universal instantiation of any of the special sciences, has been around a long time — so long, in fact, that it is now a bit archaic. One of the few twentieth century philosophers to work on this theme was Husserl, and his conception of a universal science is frankly anti-naturalistic. This makes his position an outlier, but it also makes it interesting. I could have built up a non-natural conception of universal biology based on Husserl’s sense of universal science, but I don’t think this would be appropriate for a room full of biologists and origins of life researchers.

To get a better handle on Martin Dominik’s conception of a universal biology I looked up some of his papers, and these proved to be interesting. In particular I read “The detection of extra-terrestrial life and the consequences for science and society,” and “Invited Pesek lecture: Exploration rather than speculation–assembling the puzzle of potential life beyond Earth,” both of which provided food for thought. In the latter paper Dominik wrote:

“We readily accept that the concepts of physics and chemistry apply throughout the cosmos and are valid for all time, but should this not make us wonder whether biology is universal as well, and not just a special feature that only applies to planet Earth?”

This is a little like applying the nomothetic/ideographic distinction to the whole of biology. We could frame it like this: is biology a nomothetic science (physics) or an idiographic science (like history)? My first response to this is that, of course, biology is universally applicable, and that is must be a nomothetic science. However, looking a little more closely raises some interesting philosophical questions. For example, suppose that something like life is common in the universe, but the molecular basis of life varies widely, so that there are a great many macromolecules (in appropriate combinations with each other) that can perform all of the functions of life. We could even call this the “snowflake” conception of life, in which no two instances of life are identical. In this astrobiological scenario, not only is life a cosmological imperative, but the diversity of life is a cosmological imperative.

Let’s call this astrobiological scenario 1. In 1, all life shares certain properties, but the detailed chemistry of life is different in each case. Now, if chemistry is a nomothetic science, then the laws of chemistry should hold throughout the universe, and we use one and the same science of chemistry to account for the interactions of life. However, this is distinct in a subtle way from life being nomothetic and universal. Whether astrobiologists would want to distinguish very similar macromolecules and call the study of them different sciences of life, or whether they would want to call them all life, and consider the differences to be merely contingent, I don’t know.

Another scenario, which I will call astrobiological scenario 2, is that there are a finite and probably very few ways in which life can be assembled. Let’s spice up this scenario and say that terrestrial life is an outlier, and most other life in the universe is built up of different macromolecules than those we know and love. In 2, we have many of the same problems as 1, in terms of whether astrobiologists would prefer to call it all life or to call each instance of life (each instance being a token of a type of life, which in 2 are finite in number and probably few). However, I think that making the types of life represented in the universe finite and few in number raises the likelihood that biologists would tend to treat each type of life as its own thing, sui generis, as it were. Chemistry, then, would be nomothetic, but life would be Balkanized into types, each with its own science. In this situation, we would not have a universal biology, though we might formulate some new science, a meta-biology, that was a big picture, big tent biology that included under it all specific biologies in their various forms.

In astrobiological scenario 3, life is tightly constrained and it always and only takes the form of life familiar to us on Earth. From the highly constrained nature of life, it is likely that life arises less frequently in the universe than in a case of life being less constrained, due to the particular conditions that must be present in order for life to originate. In a universe in which life is sparse but always and everywhere the same, terrestrial biology would be universal biology and there would be no need to formulate a discipline of universal biology distinct from terrestrial biology. But if life is sparse, we may well ask on other grounds whether this is really a universal biology. We could formulate a counterfactual in which life can take many forms and is universally represented in the cosmos as being the “true” form of universal biology.

To make matters more complex, some of these considerations in regard to life can be pushed back into chemistry as well. We know from being able to detect organic molecules in deep space that this chemistry is represented throughout the observable universe. However, things may look different on different planets. Each planet forms from the protoplanetary disc around a young star, and the gas and dust of the protoplanetary disk is enriched with the particular isotopes that have been blown out of stars that have previously been a supernova in the region. It is thought that supernovae may trigger the collapse of dust and gas in the interstellar medium into a protostar and its protoplanetary disk.

ALMA image of the protoplanetary disk around the young star HL Tauri.

Suppose there is a region of the universe in which the chemical elements and their isotopes that are common on Earth are rare, and elements and isotopes rare on Earth are common. Further suppose that a planetary system condenses out of these different elemental and isotopic precursors. In this case, the laws of chemistry might be the same everywhere in the universe, but what actually happens on a world of very different isotopic abundances might be different. Life emergent in this context that achieves consciousness and intelligence might come to its knowledge of chemistry differently than we did, because different chemical phenomena are commonplace. The macroscopic experiences of intelligent beings on such a world might be different enough from our macroscopic experiences that the drives to explain nature through science are also different, so that even if this intelligence formulated a chemistry, and eventually converged upon the same laws, the science would nevertheless look different. Bertrand Russell pushed this back even further to physics, and in several of his books made comments like this:

“If one could imagine intelligent beings living on the sun, where everything is gaseous, they would presumably have no concept of number, any more than of ‘things.’ They might have mathematics, but the most elementary branch would be topology. Some solar Einstein might invent arithmetic, and imagine a world to which it would be applicable, but the subject would be considered too difficult for schoolboys.” (The Philosophy of Bertrand Russell, p. 697)

Kicking around these scenarios for life and science, my second attempt at a presentation topic was “Universal Biology, Deprovincialization, and Origins of Life.” Carl Sagan used both “deprovincialization” and “deparochialization” to indicate the process that biology would undergo if confronted with an example of exolife. I had the idea to dig into the concept of deprovicialization, which is intrinsically interesting across all the sciences, and was essentially what I was doing above in discussion chemistry. There is some background to the idea. Ernst Mayr used the idea in his This is Biology:

“…most people would conclude that biology should be considered, like physics and chemistry, a legitimate science. But is biology a provincial science, and therefore not on a par with the physical sciences? When the term ‘provincial science’ was first introduced, it was used as an antonym to ‘universal,’ meaning that biology dealt with specific and localized objects about which one could not propose universal laws.” (This is Biology, p. 31)

Mayr’s references led me to Ronald Munson’s 1975 paper “Is Biology a Provincial Science?” Also, Mayr not only criticized SETI, but actually wrote a letter to a Science urging that SETI not be funded, which is something like the violation of a gentleman’s agreement not to attack another scientist’s funding, even if you disagree with the science. All of this makes the idea of deprovincialization, and Mayr’s approach to it in particular, interesting. However, I found that while there are a lot of opportunities for comment and exposition, I didn’t (and do not yet) have any definitively original perspective to bring to this discussion.

Ernst Walter Mayr (05 July 1905–03 February 2005)

Still casting about for something that I could say that wasn’t mere exposition, I went in a different direction. Here’s the abstract that I ultimately sent to NoRCEL:

ABSTRACT: Technology for exoplanet search has come into use only in the past thirty years, and we are now on the cusp of exoplanet atmospheric spectroscopy, which will reveal the atmospheric composition of some exoplanets. If life is not a cosmological imperative, if its appearance is not inevitable once the necessary prerequisites are in place, then there will be geologically complex planets that also develop chemical complexity without the particular form of chemical complexity that we identify as life. Differentiation of non-biological chemospheres from biospheres based on atmospheric spectroscopy may be possible through following the model of reconstructing stellar evolution. A taxonomy of planetary types surveyed at different periods of time in their development in different planetary systems may allow for the reconstruction of chemospheric evolution, in turn revealing a taxonomy of typical forms of chemospheric development for given planetary types. The more comprehensive our observational research program in reconstructing the history of chemospheres across diverse types of planets, the more likely we are to be able to reconstruct the typical developmental pathway of a living biosphere, allowing us to distinguish between non-living chemospheres and living biospheres, and to focus on the turning point at which the transition is made from chemosphere to biosphere.

I have a lot of work to do to flesh this out, but I am pretty sure I can encapsulate this idea within 20 minutes. I could take it in the direction of emergent complexity pluralism — the overarching idea of my previous NoRCEL presentation and of my 2019 Milan presentation — but I won’t do this unless I have more time at my disposal. In any case, it looks more likely now that I will be going to Scotland in August.

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