The Prehistory of Astrobiology
Friday 19 November 2021
How a new science comes into being is of the utmost importance to understanding science, and with a recent science like astrobiology all of the stages of the emergence of a new science have been on full view, as it were. A detailed and reflective consideration of the history astrobiology may have some lessons in the formation of contemporary sciences.
The prehistory of astrobiology includes a period during which the term “bioastronomy” was used to cover much of the same ground as what is now covered by “astrobiology.” An illustration of this can be found in Lori Marino’s paper, “Objectivity in the Study of Intelligence: The Cornerstone of New Methods and Discoveries,” which includes this definition of the domain of bioastronomy:
“The domain of bioastronomy is extremely broad. With the exception of the search for extraterrestrial intelligence, the vast majority of bioastronomy research efforts focus upon very fundamental stages of life in the universe such as organic chemistry, habitable zones, the origin of life, and the evolution of early life on Earth. A smaller proportion of bioastronomy research is devoted to other important domains on the continuum of life such as the study of the evolution of behavior and intelligence, neurosciences, the evolution of complexity, sociality, and technology.”
This paper was published in Bioastronomy 2002: Life Among the Stars, IA U Symposium, Vol. 213, 2004, edited by R. P. Norris and F. H. Stootman. Prior to this was another volume, Bioastronomy: The Search for Extraterrestrial Life — The Exploration Broadens, Proceedings of the Third International Symposium on Bioastronomy Held at Val Cenis, Savoie, France, 18–23 June 1990, which was published by Springer-Verlag in 1991. This latter volume defines bioastronomy as follows:
“Building on the discoveries of modem ground-based and space astronomy, the international community of scientists formed a new branch of astronomy, bioastronomy, which is dedicated to the study of the existence of life in the universe and the search for evidence of intelligent life.”
This volume also notes, “In 1982 the International Astronomical Union created a new commission (№ 51) devoted to bioastronomy.” The creation of new institutions — commissions, journals, regularly recurring conferences, university departments — plays a role not only in the founding of a new science, but in shaping that science and directing its future development.
The Oxford English Dictionary provides a use of “astrobiology” as early as 1898, but it is not until 1941 that we get a definition of astrobiology (“The subject of astrobiology — the consideration of life in the universe elsewhere than on earth — is one that has been so often and so inadequately treated”) that is essentially in agreement with its use today. The OED provides a use of “bioastronomy” from 1956, so it appears that “astrobiology” is the older term, but “bioastronomy” was used in its contemporary sense from its inception, so that it seems likely that bioastronomy was purposefully coined to identify a distinctive and novel approach to biology — what we could characterize as biology as a space science. New terms are introduced for new concepts that are still in the process of clarification and explication, even as older terms are adapted and change in their meaning. “Astrobiology” and “bioastronomy” existed side-by-side for some decades, with approximately the same meaning, until “astrobiology” essentially won out.
With both astrobiology and bioastronomy converging on a common field of research at about the same time — the mid-twentieth century, which is also the calendar epoch for BP (before present) dating, and will continue to be a reference point over geological time because of the radioactive fallout from nuclear explosions — clearly there was a perceived need to found a new interdisciplinary specialization that is the natural extension of understanding life naturalistically and attempting to get a grip on the place of life in the cosmos. There is more than one way to fill such a gap. As we saw from the definition of bioastronomy, above, the idea of SETI was incorporated from the beginning, but with astrobiology, SETI advocates have had to struggle for the recognition of their work to be considered a legitimate part of astrobiology. This may have played a role in the eventual success of astrobiology over bioastronomy; NASA’s period of allowing no reference whatsoever to SETI in its contracts and undertakings may have played a role in steering astrobiology to a more prominent role than bioastronomy.
There is also a prehistory of astrobiology to be found in the concept of exobiology (two initial uses in 1960 are cited by the OED), which term has partly been replaced by astrobiology, and partly has been narrowed in its scope to mean life specifically not of Earth, whereas astrobiology is taken, by contrast, to be concerned with all life, terrestrial and extraterrestrial, in its cosmological context. Xenobiology is yet another term, with the first use listed in the OED as 1954 from a Heinlein story.
Lori Marino in the essay cited above goes on to say, “The thesis of this plenary address is that these biases and assumptions limit the objectivity of the study of intelligence and complex behavior within the context of bioastronomy. Three closely related biases or assumptions about intelligence and the nature of the human species are discussed: Scala Naturae thinking, the anthropic principle, and the teleological assumption.” She develops this theme in the remainder of the paper. Since Marino is concerned with the study of intelligence, SETI-like concerns are never far from her conception of bioastronomy. Marino’s interest in intelligence leads her to the consideration of ideas that could safely be kept at a distance by a narrow parsing of astrobiology, but cannot be so easily avoided in more SETI-specific bioastronomy.
Whereas in the not-too-distant past I would have been ready to pile on with the criticism of Scala Naturae thinking, the anthropic principle and what Marino calls the teleological assumption, I now am a little more cautious. There is much in these ideas that is wrong and systematically misleading (as Gilbert Ryle would have said), but there is also still much of value in them. In my philosophical maturity (which I think I can authentically claim, being in my late fifties), I have come to appreciate how the mythological and philosophical systems of the past, even when they seem to be the highest flights of imaginative fantasy, are still tightly bound to the familiar world of human experience, which we now express in terms of science, as well as in terms of more modern intuitions. Platonism is, or can be, the height of artificiality, and can be used to falsify the world, but there are respects in which Platonism is an amazingly intuitive way to view the world, and we neglect its insights at our peril. (Similar considerations hold for the “idealism” of the idealistic school of thought in philosophy of history, the best known representative of which is Collingwood, but we can also include Croce among the “idealists.” Collingwood’s idealism could more rightly be called methodological idealism, and it could be contrasted to an ontological idealism that is not present in Collingwood’s philosophy of history.)
In the same spirit of distancing ourselves from traditional ideas like the Scala Naturae, we always remind ourselves that correlation is not the same as causality, and we cite interesting instances of non-causal correlation (the examples I have heard are ice cream sales and shark attacks — both increase in the summer — and the correlation between spelling ability and foot size among children — children with larger feet spell better because they are older), but this caution itself should be regarded with caution, because correlation is a necessary condition, but not a sufficient condition, of causality. If there is no correlation, there is no causation, so correlation is certainly worthy of our notice if we are looking for causality. The fact that we seek alternative causal explanations for correlations that are not causal shows that we understand that there is some kind of explanation even for the non-causal correlation.
There is always a tension in our relation to tradition — what to keep, and what to discard, what to adapt and how to adapt it. The complexity forced upon us by this tension can be relieved by a revolution that insists upon clearing away the past and starting with a clean slate — a blank slate — with new terminology and new concepts. We saw this play out with the Enlightenment, which, in its development, has continued its unfolding abolition of tradition. Marino’s essay is a tribute to this ongoing wiping of the slate clean, pronouncing upon the errors of traditional ideas, which are to be replaced by the truly scientific concepts of bioastronomy. While this would not be done in the name of bioastronomy today, but rather in the name of astrobiology, the project continues.
The revolutionary seeking of a blank slate for science can be understood as the Enlightenment returning to its fons et origo and now dictating the terms upon which science is to advance. The scientific revolution is older than both the Enlightenment and the industrial revolution, and it was the scientific revolution that made these subsequent movements possible. Though the Enlightenment and the industrial revolution came later, they revolutionized society to a far greater extent, and out-paced science as the driving force of history. Science has been, in a sense, preempted by the Enlightenment and the industrial revolution, which I could also formulate by saying that a nascent scientific civilization was pre-empted by the advent of Enlightenment civilization and industrialized civilization.
Is it possible that, if Enlightenment civilization and industrial civilization should enter into a crisis, that scientific civilization could come from behind and become the dominant force in history again, and in place of the Enlightenment and industrialization? I do not consider this likely, but the very idea of the possibility suggests a further reflection.
I have often noted that the greatest changes that have overtaken humanity — the agricultural revolution, the advent of civilization, and industrialization — have been entirely unplanned. Today we try to plan for growth and for the buildout of infrastructure and services, but this still isn’t the planning of the course of civilization. That has not been planned, but has happened by blind impulsion. But science, too, advances by blind impulse. I noted last week that there is no science of science, although the idea has been around and has a certain currency. The fact that we have no science of science means that science grows unplanned and unbidden. We don’t understand it, and we don’t control it.
If a scientific civilization were to emerge under these circumstances, it would be as unplanned and as blind as the agricultural revolution and industrialization. Even with science, apparently the highest expression of human rationality to date, we are at the mercy of forces we do not understand.