acceptable means of neutralizing the sceptic can be invoked. Carl Sagan (1983) thus appeals to the history of deprovincialization of our world-view since the sixteenth century in this context. This history reveals the reluctant acceptance of the fact that our Sun is merely one of 400 billion stars, that there is nothing special about us or our planet, and that we emerged along a common evolutionary process with other animals. The history of deprovincialization cannot be appealed to as proof that ETI exist, but, says Sagan, it urges caution in accepting the sceptic’s standpoint. It is worth noting that, while Carl Sagan’s appeal to the assumption of mediocrity is a valid counter to the assumption of uniqueness, neither assumption can generate its own truth. Ultimately, however, ‘the only valid approach to the question is experimental’ (Sagan, 1983: 113).
Is SETI a paradigm in the Kuhnian sense? Apart from the optimism of its exponents it is not committed to any revolutionary epistemological rupture with the past nor does it reflect a crisis in any contemporary branch of science. Yet it does exhibit a set of ground rules and doctrines characteristic of a Kuhnian paradigm. Its scientific credentials are underpinned by three fundamental features of the universe. First, the universe is believed to be uniform with the same essential building materials, the same chemical elements, functioning according to universal natural laws. In fact one essential question which SETI has raised concerns the universality of biological laws. Kepler, Galileo, Newton and Einstein postulated physical laws which dominated the universe. The question at stake in the extraterrestrial life debate is whether there are similar universal biological laws. The basic chemicals of life are widely distributed throughout the universe. As noted, the appeal to uniformitarianism is only fallacious if it is claimed that similar consequences must follow from similar conditions. The assumption that the universe is homogenous and isotropic also simplifies models used to describe it.
The second feature of the universe is supported by two major revolutions affecting modern science: the Copernican revolution revealed that we are not privileged in our location and the Darwinian revolution showed that we are not a privileged species. There is no unique spot, or centre, in the universe; there is nothing unique about our Sun, and no reason to assume that events on our planet could not happen elsewhere. In 1996 the Hubble telescope provided one of the deepest-ever views of the universe, forcibly demonstrating that the Milky Way Galaxy is only one of billions of galaxies in the universe, and is not even centrally located. Modern cosmology supports SETI’s plausibility: the universe has no centre, no outer limit or surface, no privileged place, but continuous expansion. Further developments in modern cosmology include speculations that there are many universes, in which case it cannot be claimed that the universe itself has a privileged status!
Third, the universe is massive: within telescopic range are over a hundred billion galaxies, each containing hundreds of billions of stars. Or, as it is often said, there are more stars than there are grains of sand on all the beaches on Earth. It must, however, be stressed that the appeal to these three features plays a
47
heuristic rather than a probative role in SETI research; there is no substitute for an empirical investigation.
In addition, SETI researchers are committed to two basic beliefs. The first is the belief that intelligent alien life-forms will have similar thought patterns to those displayed by intelligent life on Earth. In this respect SETI has been described as a search for extraterrestrial human intelligence (SETHI). This does not have to commit SETI scientists to a search for other human beings. Carl Sagan has argued that, given different evolutionary programmes and different environments, it would be astonishing if ET life resembled ours. But while biological diversity is expected, there is a belief among SETI scientists in a similar technology. This is because of the universality of physical laws. Thus the authors of the Project Cyclops Report state that:
Regardless of the morphology of other intelligent beings, their micro-scopes, telescopes, communication systems, and power plants must have been at some time in their history, almost indistinguishable in working principles from ours. To be sure there will be differences in the order of invention and application of techniques and machines, but technological systems are shaped more by the physical laws of optics, thermody-namics, electromagnetics, or atomic reactions on which they are based, than by the nature of beings that design them.
(Oliver and Billingham, 1973: 4)
SETI scientists are not committed to the view that every sequence in the evolution of life towards a technological culture has to be replicated. This would be impossible. What matters is that, by one way or another, intelligent extra-terrestrials develop a technological ability similar to ours. This may involve many alternative sequences – as in the evolution of science on Earth – and many different ways of arriving at the same goal, given broadly similar problems. If physics is universal, they will make use of the same laws, although discoveries and applications associated with them will be diverse. They may discover how to harness the power of electricity in ways that are not dissimilar to ours, but it would be very unlikely for them to invent electric toasters or battery-operated door chimes. With a broad agreement over the principles of science, it is presumed that there would be few problems in constructing a dialogue based upon technology, science and mathematics. This presumption is not without its critics (Weston, 1988).
The second belief is that communication with other life-forms will be via electromagnetic signals at some ‘magic’ frequency that corresponds with fundamental properties of atoms, such as hydrogen, which are commonplace throughout the universe. A further aspect of the SETI paradigm, which shall be examined here, are the assumptions and doctrines built around the Drake equation. The main components of the equation will be briefly examined here,
48
Pages: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104