John Barrow, The infinite book: a short guide to the boundless, timeless, and endless Panteon books, 2005. pp. 208-211 ... So we suggest that if we live in a simulated reality we should expect occasional sudden glitches, small drifts in the supposed constants and laws of Nature over time, and dawning realisation that the flasws of Nature are as important as the laws of Nature for our understanding of true reality. HOW SHOULD WE THEN LIVE? '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 rich, 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. ' Robin Hanson Unusual consequences seem to follow if we take seriously the idea that there exists an infinite number of possible worlds which fill out all the possibilities. We can imagine how an extension of some of the science and technology we have at the moment would enable our successors to do some of these things. The implications for the nature of teh world taht we experience and its likely fallibility are striking, worrying even, and they take us back to the words the philosopher David Hume wrote at the end of the eighteenth century. Hume's sceptical dialogues about many of the arguments for the existence of God that were fashionable at the time pick on the presumptions in these arguments about the perfect nature of creation, the uniqueness of the Deity and so forth. Here is what he had to say about many worlds and their likely defects: 'You must acknowledge, that it is impossible for us to tell, from our limited views, whether this system contains any great faults, or deserves any considerable praise, if compared to other possible, and even real systems. ... If we survey a ship, what an exalted idea must we form of the ingenuity of the carpenter, who framed so complicated, useful and beautiful a machine? And what surprise must we entertain, when we find him a stupid mechanic, who imitated others, and copies an art, which, through a long succession of ages, after multiplied trials, mistakes, corrections, deliberations, and controversies, had been gradually improving? ... Many worlds might have been botched and bungled, throughout an eternity, when this system was struck out: Much labour lost: Many fruitless trailes made: And a slow, but continued improvement carried on during infinite ages in the art of world-making ... This world, for aught he knows, is faulty and imperfect, compared to a superior standard, and was only the first rude essay of some infant deity who afterwards abandoned it, ashamed of his lame performance; it is the work of some dependent, inferior deity; and is the object of derision to his superiors; it is the product of old age and dotage in some superannuated deity and ever since his death has run on at adventures, from the first impulse and active force which it received from him.' Hume's tongue-in-cheek scenarios conjured up images of a host of gods of varying degrees of competence creating universes of different quality, like apprentices attempting to copy the master. But if we replace his inferior and superannuated deities by simulators, then what he envisions is a realm where simulated universes about: some good, some promising, others defective. So, if all possible worlds exist and we are living in a simulation whose laws are not quite consistent with one another, does this make any difference? Indeed, should it make any difference? It will be rather de-motivating if you are a (simulated) scientist trying to understand the way the world works. Anything could happen without reason. Not surprisingly, simulated realities are not welcomed into the scientific world-view. Philosophers take them more seriously and some have even tried to use them as arenas to discuss ethics. The problems they spawn are unusual. Robin Hanson has suggested the possibility of being in a simulated reality might produce its own influences on how you should act. Simulated experiences, no matter how real they may seem, are much more likely to be brought to a sudden and unpredictable end than typical real experiences. This suggest to Hanson that 'all else being equal you should care less about the future of yourself and of humanity, and live more for today'. We are familiar with the fact that in films and the theatre the star is surrounded by other good actors who have to interact with the star, but as you move further away from the star then extras and low-paid jobbing actors can fill in the crowd scenes and non-speaking parts at low cost. Likewise in a simulated reality, the characters far from your action may just be fake simulated characters and you shouldn't worry too much about them. Above all, Hanson suggests, if you are part of somebody's simulation, be entertaining! Be famous! Be a pivotal person! This will increase chances of your simulated existence continuing, and that others will want to resimulate you in the future. Fail to have these characteristics and you could become like the soap-opera character who quickly gets written out of the show, and taking a long holiday in Vladivostok, never to return. As we look around at the way people in the news do behave, we are drawn to the conclusion that we must be living in a simulation! However, none of this is very persuasive. How you should behave depends entirely on the moral stance of the simulators. If they like to be entertained then you will do well to be entertaining. But if they are dedicated to a noble purpose, you might have the greatest chance of continuing re-creation and simulation by being a martyr for a just and good cause. While we do not suggest that these codes of behavior are taken seriously as the basis for how to live your live, they do bring sharply into focus the central problems of moral philosophy and our responses to them. If simulated realities are the commonest and we are in one of them, it would be worrying if they are simulations of the sort that we know. But why should they be? If we had always used the word 'simulation' to describe the result of a one-off act of creation by God then we are in a very similar situation, albeit with a Simulator of a greater sort. These consequences for life in simulated realities have led some to regard them as strong arguments against the existence of other wrolds. If most of these worlds are virtual, then they can display illusory laws of physics and we are on a slippery slope to knowing nothing at all because there is no reliable knowledge to be had. It is the counterpoint to solipsism and has many of the same paralyzing consequences for any future thinking. If all possibilities are infinite and actual, then reality contains rather more than we can bear.