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Project Progress

Philosophical Issues in Astrobiology (dm)

Our project deals with analysis of the differences in methodology between historical science and experimental science vis-à-vis the testing of hypotheses, as applied to astrobiology. We have complted a more accurate account of the research practices of experimental scientists and historical research the previous year. We discovered that experiment plays a large number of different roles in science besides the classical role of testing hypotheses. We also determined that classical experimental research is best thought of in terms of an experimental program rather than (as traditional) isolated experiments. An experimental program involves a series of experiments each one designed in light of the results of previous experiments. Further investigation revealed that this is the central problem with robotic experiments like the Viking Lander metabolic experiments. One cannot determine in advance of actual experimental data what controls are adequate to rule out false positives and false negatives. These conclusions have implications for the development of instrument packages for detecting extraterrestrial life, namely that the probability of success is higher if one takes an historical approach (which involves emphasizing diversity of evidence collected and minimizing the use of antecedently designed controlled experiments).

We also began working on the question of whether “life” can be defined. Preliminary investigations suggest that trying to define “life” is a mistake. The purpose of definition is to analyze the meanings of terms. Supplying the current meaning of the term “life” is no more likely to provide us with an understanding of the inherent nature of life than supplying the sixteenth century meaning of “water” is likely to provide us with an understanding of the inherent nature of water. What is required is a theoretical framework for biology that would support identity statements analogous to “water is H20.”