1. There is a degree of uncertainty in the measurement of the entropy at any instant, but for simplicity this may be neglected in the present discussion. It may be more customary to regard the entropy as the average logarithm of the microscopic properties of the system taken over a brief period of time; but this introduces an uncertainty because the system may have to be considered as changing toward greater entropy as time proceeds.
2. This was pointed out by the late Dr. John Von Neumann in his Vanuxem lectures at Princeton University in 1953.
3. H. F. Blum, ‘On the origin of self-replicating systems’, Rythmic and Synthetic Processes in Growth (ed. by D. Rudnick), Princeton University Press, Princeton, 1957 and ‘On the Origin and Evolution of Living Machines’, American Scientist
49 (1961) 474–501.
4. I may again refer to Von Neumann who in the same lecture cited above, entertained the possibility of a machine that could duplicate itself, but expressed his inability to imagine a machine that could create itself. I would refer this difficulty to our inability to describe the multi-faceted evolutionary process that lies back of any machine, real or imaginary, that we may conceive. See also H. F. Blum, ‘On the Origin and Evolution of Human Culture’, American Scientist
51 (1963) 32–47.