Peter S. Jenkins, Historical Simulations - Motivational, Ethical and Legal Issues, 11 J. Futures Stud. 23, Aug. 2006.:
A future society will very likely have the technological ability and the motivation to create large numbers of completely realistic historical simulations and be able to overcome any ethical and legal obstacles to doing so. It is thus highly probable that we are a form of artificial intelligence inhabiting one of these simulations. To avoid stacking (i.e. simulations within simulations), the termination of these simulations is likely to be the point in history when the technology to create them first became widely available, (estimated to be 2050). Long range planning beyond this date would therefore be futile.
This is a nearly perfect abstract. My only complaint is that it does not accurately reflect what is actually in the paper.