The Prospect of von Neumann probes and the implications for the Sagan-Tipler debate
There are four papers in this special issue on the prospect of von Neumann probes and their implications for SETI. They all point in the same direction. von Neumann probes reside at the core of the Sagan-Tipler debate which, given recent technological advances in robotics and other disciplines, deserve a re-appraisal. In conjunction with the failure of radio searches thus far, the search for a broader spectrum of technosignatures has been admitting a broader range of scientific activity to the SETI pursuit beyond radio (and optical) astronomy. The advent of space telescopy has broadened access to the cosmos across the electromagnetic spectrum. Planetary exploration has opened nearby alien worlds for us to examine physically and extrasolar planets to observe with ever greater sophistication. Astrobiology has emerged as a recognised discipline to contribute directly to the SETI pursuit. Scientists have been actively engaged in search – both into the cosmos and on Earth itself. Engineers, as wielders of technology, offer an approach based on Richard Feynman’s dictum: “what I cannot create, I do not understand”. Developing self-replication technology may provide us with insights into a broader astrobiology quest as life without organic molecules. For the SETI quest itself however, the creation of self-replication technology puts the Copernican principle under scrutiny by shifting the balance towards Tipler’s stance away from Sagan’s. The von Neumann probe is no longer the theoretical concept of the 1980s – today, it is a practical engineering problem.