Deutsch gives Malthus as an example of a failed pessimistic prediction - at 23:00. However, it still looks as though Malthus is likely to have been correct. Populations increase exponentially, while resources expand at most in a polynomial fashion - due to the light cone. Deutsch discusses this point 38:00 minutes in, claiming relatavistic time dilation changes this conclusion, which I don' t think it really does: you still wind-up with most organisms being resource-limited, just as Malthus described.