The Artful Universe Expanded, by John Barrow p. 53

Once this capability to simulate universes is achieved, fake universes 
will proliferate and will soon greatly outnumber the real ones.  Thus, 
Nick Bostrom has argued that a thinking being here and now is more 
likely to be in a simulated reality than a real one.  

Motivated by this alarming conclusion, there have even been 
suggestions as to how best to conduct ourselves if we have a high 
probability of being simulated beings in a simulated reality.   Robin 
Hanson suggests that you should act so as to increase the chances of 
continuing to exist in the simulation or of being resimulated in the 
future: 'If you might be living in a simulation then all else-equal 
you should care less about others, live more for today, make your 
world look more likely to become rick, expect to and try more to 
participate in pivotal events, be more entertaining and praiseworthy, 
and keep the famous people around you happier and more interested in 
you.' In response Paul Davies has argued that this high probability of 
living in a simulated reality is a reductio ad absurdum for the whole 
idea that multiverses of all possibilities exist.  It would undermine 
our hopes of acquiring any sure knowledge about the Universe.