During antiquity, the astronomical questions of the day and the methods used to formulate and answer them were clearly within the realm of philosophy. That changed most notably in the sixteenth century when Tycho Brahe turned astronomy into a modern empirical science by formulating (in principle) testable hypotheses, figuring out how to test them, building the proper instruments, and making – for that time – very accurate and systematic observations of the sky. These observations eventually led to the modern view (...) of the solar system and ultimately the rejection of the classical Aristotelian worldview. Since then, the exploration of space has been located clearly in the realm of natural science – and, to an increasing extent, technology. In parallel to that, space has – at least since World War II –to a high degree been a place for military and political ambitions and activities. The scientists that have been involved in space exploration have mainly been physicists, together with some chemists and geologists. Lately, the exploration of space has engaged more and more biologists in the search for extraterrestrial life. The international space station, along with plans to send humans to Mars, has led to an increased involvement of medical science. If present speculations about space tourism and mining on planets, moons, and asteroids hold true, in the future we will probably see many new professions dealing not just with exploration, but also exploitation of space. Philosophy has never totally left the realm of space exploration. As space exploration and exploitation become more and more interdisciplinary, and as space becomes a bigger part of our lives, it will be time once more for philosophy to turn its attention towards space. The mission for philosophers is not to indulge in speculations over questions that are better dealt with by empirical methods. Ther are, however, several questions connected to the exploration and exploitation of space that are of a philosophical nature and that deserve to be examined seriously from a philosophical perspective. I believe that philosophical scrutiny of these questions will be to the benefit of both space exploration and philosophy. Interesting and, indeed, important philosophical questions arise in many areas of space exploration. Some of the most interesting and important ones relate to the search for extraterrestrial life, of which some will be presented here. I will not attempt to answer these questions here. Instead, this chapter should be seen as an introduction to some of the philosophical questions raised by astrobiology. (shrink)

The well-known argument against the Search for ExtraTerrestrial Intelligence (SETI) due to George Gaylord Simpson is re-analyzed almost half a century later, in the light of our improved understanding of preconditions for the emergence of life and intelligence brought about by the ongoing “astrobiological revolution”. Simpson’s argument has been enormously influential, in particular in biological circles, and it arguably fueled the most serious opposition to SETI programmes and their funding. I argue that both proponents and opponents of Simpson’s argument have (...) occasionally mispresented its core content. Proponents often oversimplify it as just another consequence of biological contingency, thus leaving their position open to general arguments limiting the scope of contingency in evolution (such as the recent argument of Geerat Vermeij based on selection effects in the fossil record). They also tend to neglect that the argument has been presented as essentially atemporal, while referring to entities and processes that are likely to change over time; this has become even less justifiable as our astrobiological knowledge increased in recent years. Opponents have failed to see that the weaknesses in Simpson’s position could be removed by restructuring of the argument; I suggest one way of such restructuring, envisioned long ago in the fictional context by Stanislaw Lem. While no firm consensus has emerged on the validity of Simpson’s argument so far, I suggest that, contrary to the original motivation, today it is less an anti-SETI argument, and more an astrobiological research programme. In this research programme, SETI could be generalized into a platform for testing some of the deepest assumptions about evolutionary continuity and the relative role of contingency versus convergence on unprecedented spatial and temporal scales. (shrink)