SETI and the problem of scientific methodology

Questions regarding the scientific status of SETI inevitably give rise to further questions concerning the very nature of science itself. The traditional or received view during the first half of the twentieth century was that of logical empiricism, according to which all scientific theory must be grounded in observational experience. A fundamental distinction was drawn between  observational terms and theoretical terms, and a central part of the logical empiricist programme was given to the attempt to show how theoretical terms could be interpreted on the basis of observational experience. The meaning of scientific statements would be examined with reference to observations which provided verification. Observational discourse was taken to raise no problems, as it referred directly to experience. Another central feature of the received view was that the history of science exhibited a pattern of progress, recording the gradual removal of superstition, prejudice and erroneous theories.

During the latter half of the twentieth century the received view of science came under attack from numerous sources, among whom were Sir Karl Popper, Thomas Kuhn and Paul K. Feyerabend. While the fundamental differences between the three philosophers continue to be debated among philosophers of science, the damage they inflicted upon the received view of scientific methodology would seem to be irreparable. Popper demolished the idea that empirical verification was the essence of scientific methodology and maintained that the most important characteristic of honest science was the potential for hypotheses or conjectures to succumb to falsification.

Popper’s doctrine of falsification provided him with a criterion of demar-cation between genuine science and pseudo-science.  Valid scientific theories are those subjected to, and able to withstand, the test of falsifiability until they are eventually overthrown. Scientific theories were not ultimately reducible to foundational observational experiences and they cannot ever be accepted as final truths; they are conjectures awaiting refutation. Thus the function of the theoretician is to propose scientific conjectures, while the function of the experimenter is to devise every possible way of falsifying these theoretical hypotheses. The confirmation of a hypothesis, maintained Popper, has no scientific meaning.

Popper is one of the few among modern philosophers of science to have influenced the work of scientists, and his appeal to potential falsification captures those moments in science where research efforts are devoted to demonstrating the falsity of particular claims. This, of course, is relevant to our understanding of the status of SETI. Scientists engaged in SETI are unlikely  to cling tenaciously to hypotheses concerning colonies of extraterrestrials on Mars once overwhelming evidence from space probes provides falsification. Only members of cults and various fringe activities will go on to produce exotic reasons for maintaining their beliefs against overwhelming contrary evidence. It will be maintained throughout this discussion that, as a  branch of scientific research, SETI conforms to Popperian criteria for demarcation.

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Further objections to the received view of logical empiricism were developed by Paul K. Feyerabend and Thomas Kuhn in the 1960s, and these continue to generate controversy (Munévar et al., 2000). In a series of polemical essays Feyerabend (1975) not only rejected the received view of logical empiricism and went beyond Popper’s critical rationalism; he actually attempted a demolition of all attempts to construct a methodology of science. Opposing the very idea of scientific methodology, Feyerabend drew a sharp contrast between the actual history of science and the so-called logic of science, arguing that the most successful scientific research programmes have never proceeded according to rational methodologies at all. He introduced a slogan ‘anything goes’, and in detailed studies of Galileo’s defence of Copernicanism argued that the ultimate success of Galileo’s research programme lay not in any superior scientific method, but in a variety of ways whereby opponents were disarmed and supporters were convinced that they were on the right track. Like many great thinkers, Feyerabend was to revise his position throughout his life, but his fundamental message remained intact: namely, that there are numerous examples throughout the history of science where embryonic research programmes, however much they depart from established theories and facts, have revealed an ability to flourish, and add to the store of human knowledge, and possibly overturn the existing orthodoxy. SETI, so it would seem, despite charges that it is a science without a subject-matter, is very much akin to those research programmes which, according to Feyerabend, require breathing space and the relaxation of criteria for rational assessment.

Thomas Kuhn was a contemporary of Feyerabend, who shared the view that the actual history of science did not fit well with the normative image of science that was projected by the logical empiricists. In The Structure of Scientific Revolutions (1962) Kuhn appealed to case studies in the history of science in order to establish the view that scientific development was more dependent upon a set of shared presuppositions, practices, values and beliefs, held within a community of scientists, than on the accumulation of facts upon observational foundations, as the logical empiricists had maintained. Initially, Kuhn adopted the term ‘paradigm’ when referring to a particular conceptual framework within which certain facts and theories were meaningful. Great scientific revolutions, he argued, were akin to political revolutions whereby the existing orthodoxy, when confronted with anomalies, degenerated into a state of crisis before being replaced by the new order. A major transformation in scientific thought, he held, is not so much brought about by the falsification of the old  theoretical framework or the verification of the new. Rather, the transformation (which became known as a ‘paradigm switch’) involved a change in both the background theory and the observations bound up with it. In this way Kuhn replaced the linear notion of scientific progress with the idea of periodic conceptual transformations or changes in the way that science is actually conducted. A scientific revolution, Kuhn argued, does not lead to a better or worse standpoint, as the meaning of the terms within one paradigm may be incommensurable

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