The Timing of Evolutionary Transitions Suggests Intelligent Life is Rare

The 'Oumuamua Controversy: Bayesian Priors and the Evolution of Technological Intelligence

Was the interstellar object 'Oumuamua a light sail constructed by aliens (hypothesis A) or can it be explained by more natural processes (hypothesis N)? To compare these two hypotheses, a Bayesian analysis of the Sagan standard is introduced. I show that apparently contradictory answers are not contradictory when one is careful about the specific question one is trying to answer. Different estimates of prior odds play the dominant role in the controversy. The existence of technological alien civilizations is largely an issue of evolutionary biology, not astronomy. I argue that, based on tens of millions of independent evolutionary experiments here on Earth, the probability of technological alien civilizations is somewhere between zero and tiny. This extremely low prior decreases the probability of A being favored in the posterior odds, but counterintuitively increases the power of the new evidence to favor A.

Ecocentrism and Biosphere Life Extension

The biosphere represents the global sum of all ecosystems. According to a prominent view in environmental ethics, ecocentrism, these ecosystems matter for their own sake, and not only because they contribute to human ends. As such, some ecocentrists are critical of the modern industrial civilization, and a few even argue that an irreversible collapse of the modern industrial civilization would be a good thing. However, taking a longer view and considering the eventual destruction of the biosphere by astronomical processes, we argue that humans, a species with considerable technological know-how and industrial capacity could intervene to extend the lifespan of Earth's biosphere, perhaps by several billion years. We argue that human civilization, despite its flaws and harmful impacts on many ecosystems, is the biosphere's best hope of avoiding premature destruction. We argue that proponents of ecocentrism, even those who wholly disregard anthropocentric values, have a strong moral reason preserve the modern industrial civilization, for as long as needed to ensure biosphere survival.

Catastrophe risk can accelerate unlikely evolutionary transitions

Intelligent life has emerged late in Earth's habitable lifetime, and required a preceding series of key evolutionary transitions. A simple model (the Carter model) explains the late arrival of intelligent life by positing these evolutionary transitions were exceptionally unlikely 'critical steps'. An alternative model (the neocatastrophism hypothesis) proposes that intelligent life was delayed by frequent catastrophes that served to set back evolutionary innovation. Here, we generalize the Carter model and explore this hypothesis by including catastrophes that can 'undo' an evolutionary transition. Introducing catastrophes or evolutionary dead ends can create situations in which critical steps occur rapidly or in clusters, suggesting that past estimates of the number of critical steps could be underestimated. If catastrophes affect complex life more than simple life, the critical steps will also exhibit a pattern of acceleration towards the present, suggesting that the increase in biological complexity over the past 500 Myr could reflect previously overlooked evolutionary transitions. Furthermore, our results have implications for understanding the different explanations (critical steps versus neo-catastrophes) for the evolution of intelligent life and the so-called Fermi paradox-the observation that intelligent life appears rare in the observable Universe.

Drake-like Calculations for the Frequency of Life in the Universe

This article is intended to provide a review of some modifications to the Drake equation, a 1961 concept presented by Frank Drake to determine the number of extra-terrestrial civilizations able to communicate. A reduced version of the Drake equation will then be presented. This can be used to estimate an important question for astrobiology, the frequency with which planets are habitable. Finally, a concept is presented that can also integrate the habitability of moons into the reduced Drake equation.

Reconfiguring SETI in the microbial context: Panspermia as a solution to Fermi's paradox

All SETI (Search for Extraterrestrial Intelligence) programmes that were conceived and put into practice since the 1960s have been based on anthropocentric ideas concerning the definition of intelligence on a cosmic-wide scale. Brain-based neuronal intelligence, augmented by AI, are currently thought of as being the only form of intelligence that can engage in SETI-type interactions, and this assumption is likely to be connected with the dilemma of the famous Fermi paradox. We argue that high levels of intelligence and cognition inherent in ensembles of bacteria are much more likely to be the dominant form of cosmic intelligence, and the transfer of such intelligence is enabled by the processes of panspermia. We outline the main principles of bacterial intelligence, and how this intelligence may be used by the planetary-scale bacterial system, or the bacteriosphere, through processes of biological tropism, to connect to any extra-terrestrial microbial forms, independently of human interference.