Planet Formation and Panspermia. Группа авторов
Читать онлайн книгу.
which need to integrate understanding of natural processes from physical science with the human perspective which frames all our actions. It ranges from relatively innocuous lack of worry for the fate of Earth billions of years hence, when Sun enters the post-Main Sequence phase of its evolution, to much more malignant forms of ecological and climate neglect for problems facing our children and grandchildren in the context of climate change/ocean pollution/loss of biodiversity. In both cases, there is a contrast between clear predictions of physical science (“our Sun has finite Main Sequence lifetime, after which it will enter the red giant/asymptotic giant phases” or “the continuous pumping CO2 into the atmosphere leads to increased greenhouse effect, hence climate change”) and our explicit or implicit failure to observe any effects—or any obvious effects—at present. If we were not enthralled by chronocentrism, we would have immediately noticed that there is not a trace of doubt that anthropogenic climate change is real and incredibly threatening. The debate on the relevant timescales would lose much of its rhetorical strength if we accept that for humanity as such (and even terrestrial biosphere itself) it is hardly relevant whether drastic consequences will occur in 50, 75, or 150 years from now. Of course, it does matter from the standpoint of an individual lifetime—which also increases rather quickly in historical terms—but not from the standpoint of the species or the biosphere. Only the narcissistic underpinnings of chronocentrism make us discount things farther in the future than our own lifetime (and perhaps, for the equally selfish and narcissistic reasons, lifetimes of our biological children). The example of climate change is the most important and momentous, but there are other examples which demonstrate that chronocentrism is quite a dangerous belief.4
Of course, one should not blithely accept chronocentrism’s opposite— what one can call temporal Copernicanism—either. It is almost a tautology that all epochs are not equally important, interesting, or relevant. The classical steady-state cosmological theory has tried to implement the idea of temporal Copernicanism most widely and literally, under the name of the “Perfect Cosmological Principle” ([3.10, 3.6]). The Perfect Cosmological Principle simply states that the universe is uniform in 4-D spacetime. The implication is, clearly, that all epochs are, on the average, the same. Although the steady-state theory has been a powerful alternative to the standard relativistic cosmology in the central formative period of the “Great Cosmological Controversy” (1948–1965), it was eventually refuted by empirical data [3.36]. There are other, much subtler modern versions of temporal Copernicanism which, as argued by Ćirković and Balbi [3.16], need to be resisted as well. These include reasoning in astrobiology and SETI studies which explicitly or implicitly assume that our epoch is typical for epochs containing living beings and intelligent observers (e.g., [3.50]). A partially confounding factor here is that we cannot take an agnostic position regarding cosmological pre-conditions for life and intelligence, since in the last quarter century or so we have learnt a great deal about those. So to what extent we take into account this, in philosophical parlance, admissible evidence, will influence our evaluation of the heuristics. Without entering this complex topic in epistemology, it is important to emphasize that the undermining of temporal Copernicanism as that of [3.16] does not mean any endorsement of chronocentrism. The truth has to be somewhere in the middle; we shall return to this point in the concluding section.
Chronocentrism has much to do with our general short-sightedness and failure to perceive and understand deeper long-term trends. It also has much to do with our rejection of large-scale, far-reaching visions of the cosmic future of humanity, such as those of the Russian cosmists, Olaf Stapledon, Arthur C. Clarke, R. Buckminster Fuller, or Gerard O’Neill. This is the clear reason why we need to emancipate ourselves from chronocentrism, as a vestige of our parochial, narrowly localized past.
Still, this does not mean that we should not draw useful lessons from the parochial past. In Book 3 of his Nicomachean Ethics, Aristotle cogently argued that: “What we deliberate about is practical measures that lie in our power… The effects about which we deliberate are those which are produced by our agency but not always in the same way.”5 Consider the implication: the proper objects for deliberation are things which are within our power—that is, which are neither predetermined nor chaotic—which have uncertain outcomes. Human intentional actions, either personal or collective, belong to this category, which is why ethics makes sense in judging them. Consider, for instance, the idea of terraforming Mars: it will neither happen randomly nor can we reasonably state that it has been foreordained since the beginning of time. This is exactly the reason why we can meaningfully debate morality of terraforming Mars and create scenarios depending on, e.g., whether there is an extant Martian biosphere or a fossil one, etc. [3.8].
There is no reason to limit ourselves to specifically human actions here. The quote of Aristotle works perfectly well for any intelligent observer anywhere in the universe. It is reasonable to suppose that extraterrestrial intelligent observers also have specific capacities and that among those capacities is the capacity to deliberate upon the consequences and meanings of their own actions.6 There is a deep sense in which Copernicanism is built into this attitude, which is exactly what we need in order to conceive of a truly global astrobiological landscape on the Milky Way level.
3.3 Cultural Evolution and Directed Panspermia
While the continuity thesis arose in connection to abiogenesis, there is no reason for it to remain constrained there; the same reasoning applies to noogenesis or any similar key transition. Again, this is of key importance when using the continuity thesis as heuristics. If some empirical data or well-motivated theoretical model appears which would indicate discontinuity, we would be justified in rejecting the continuity thesis, of course. However, as long as such empirical or theoretical insights are lacking, we should be free to use it and investigate its consequences, even if some of them are extremely speculative and far-fetched.7
While the continuity thesis suggests that the transition from non-life to life is easier than a priori thought, it does not really prescribe where and how the transition did actually occur. It is still possible that early life came to Earth from somewhere else, in particular from Mars, which had perhaps been more conductive to abiogenesis than our planet at that epoch (e.g., [3.18]). The scenario in which abiogenesis first occurred on Mars and some early life forms were subsequently transported to Earth (while, presumably, Martian life either became extinct or remained in very limited enclaves after the environmental conditions there deteriorated 3.5–4 Gyr ago; see [3.37]) is as perfectly in agreement with the continuity thesis as are any of the conventional abiogenesis scenarios on Earth. Mutatis mutandis, other forms of panspermia, are consistent with the continuity thesis and the epistemological “machinery” behind it.
Now, there is an important consideration to take into account: while some panspermia could clearly occur naturally, and in an optimistic case, be effective very slowly over interstellar distances (see also the chapter by Balbi in this volume [3.7]), the constraints are much weaker in the case of its technogenic version, directed panspermia. The latter has been suggested by two titans of biochemistry, Francis Crick and Leslie Orgel, as a halfserious solution for multiple problems facing origin of life research: maybe our planet has been seeded, intentionally or not, with early life forms by an advanced technological civilization [3.17]. Directed panspermia is often made to sound like science fiction—which should not be taken pejoratively in the first place—although it is a scientifically legitimate hypothesis or a class of hypotheses. Critics have charged that it is untestable, although it is at least doubtful whether it is indeed so, or we should emancipate from the common myopia inherent in human short-term timescales in epistemology as well.