At the present state of our knowledge, the origin of life remains a deep mystery. That is not to say, of course, that it will always be so. Undoubtedly the physical and chemical processes that led to the emergence of life from nonlife were immensely complicated, and it is no surprise that we find such processes hard to model mathematically or to duplicate in the laboratory. In the face of this basic obstacle, one can distinguish between three philosophical positions concerning the origin of life: (i) it was a miracle; (ii) it was a stupendously improbable accident; and (iii) it was an inevitable consequence of the outworking of the laws of physics and chemistry, given the right conditions.
I wish to state at the outset that I shall argue strongly for (iii), which seems to be the position adopted by most of the SETI scientists. It is based on the adoption of three philosophical principles which, as I pointed out in the last