“The demonstration that no possible combination of known substances, known forms of machinery and known forms of force, can be united in a practical machine by which man shall fly long distances through the air, seems to the writer as complete as it is possible for the demonstration of any physical fact to be.” Simon Newcomb, Professor of Mathematics, John Hopkins University, 1901 Abstract Free will is described in terms of the useful properties that it could confer, explaining why it (...) might have been selected for over the course of evolution. These are: exterior unpredictability; interior rationality; and social accountability. A process is described that might bring it about when deployed in a suitable social context. It is suggested that this process could itself be of an evolutionary nature – that free will might “evolve” in the brain during development. This mental evolution effectively separates the internal and external contexts, whilst retaining the coherency between individual’s public accounts of their actions. This is supported by the properties of evolutionary algorithms and possesses the three desired properties. Some objections to the possibility of free will are dealt with by pointing out the prima facie evidence and showing how an assumption that everything must be either deterministic or random can result from an unsupported assumption of universalism. (shrink)