If we accept the 3 conditions listed below then we can make a convincing case that it is far, far more likely that we live in a simulation universe rather than a ‘real’ universe.
- At some point in time in some universe or plane of existence somewhere, intelligent agent(s) of some kind developed to the point of being able to create simulation universes of very high sophistication (ex. Matrix).
- The simulation minds within the simulation universe are complex enough to become ‘conscious’ in the same way that we think we are conscious.
- The intelligent agent(s) at work create many of these simulations (maybe millions/billions+).
It should be noted that the term ‘universe’ is generally defined as ‘all existing matter and space considered as a whole.’ So when we are talking about multiple universes and simulation universes we are not talking about the literal definition of universe as anything and everything that there is. It might be the case that very many or even infinite number of real or simulation ‘universes’ exist but these are universes in the sense that they are closed systems/realities. An observer inside cannot experience anything whatsoever outside of their particular ‘universe’ system.
For condition #1 we should remember that since we can only experience events within our universe and time frame it is not relevant when, where, or by whom simulations are created. (It could even be the case that 100 years in the future on Earth we humans achieve this ability and then go on to simulate our history and civilization in full realism many times over. We might start from the point the Earth cooled and fast forward/rewind through the ages. The inhabitants in this scenario would feel like very normal people on Earth.) Or it might be the case that the creator(s) lives in a universe nothing at all like ours and created many simulations with varying conditions (laws of physics etc.) until they found something interesting.
For condition #2 it is difficult to say how likely it might be that ‘simulation people’ would experience true consciousness in the way that we think we do. The whole issue of consciousness and whether a machine or program in a simulation can achieve consciousness is uncertain. It might be the case that only biological beings can achieve consciousness or it might be that sufficient complexity and mind architecture is what matters.
In condition #3 we assume that an intelligence capable of creating simulation universes would not only do so but they would create many of them. I think this is a reasonable assumption. We should remember that we only need this to happen once. We only need 1 civilization or intelligent entity in all of existence to figure out how to create these simulations and they can then go on to create billions of them. It seems to me that a civilization advanced enough to create these simulations would not have to worry much about scarcity of resources or energy so then it would be very easy to create billions and billions of simulations rather than just a few.
So how does this suggest that we live in a simulation and not a real universe? For the sake simplicity let’s imagine that the average number of conscious ‘human’ inhabitants per simulation universe is 1 million. These inhabitants are ‘conscious’ and for all intents and purposes they are absolutely oblivious to the fact that they are in a simulation. They are just like us. If we have very many of these simulations, let’s say 1 million to be conservative, then the total number of simulation people across all simulations is 1 trillion. Now let’s imagine that the ‘mother’ universe has 10 billion real conscious inhabitants… So of all the minds across the real and the simulation universes only 1/100 of them are ‘real’. So if we are sitting here experiencing consciousness but with absolutely no way of being able to tell whether everything is ‘real’ or not we can only give ourselves odds: 1/100, probably not.
Further reading: Simulation Hypothesis (wiki page).
Footnote: Nick Bostrom (writer/philosopher at Oxford) comes to a similar conclusion in ‘Bostrom’s trilemma’:
“A technologically mature “posthuman” civilization would have enormous computing power. Based on this empirical fact, the simulation argument shows that at least one of the following propositions is true:
- The fraction of human-level civilizations that reach a posthuman stage is very close to zero;
- The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero;
- The fraction of all people with our kind of experiences that are living in a simulation is very close to one.
If (1) is true, then we will almost certainly go extinct before reaching posthumanity. If (2) is true, then there must be a strong convergence among the courses of advanced civilizations so that virtually none contains any relatively wealthy individuals who desire to run ancestor-simulations and are free to do so. If (3) is true, then we almost certainly live in a simulation. In the dark forest of our current ignorance, it seems sensible to apportion one’s credence roughly evenly between (1), (2), and (3).
Unless we are now living in a simulation, our descendants will almost certainly never run an ancestor-simulation.”
Bostrom not only presents a much simpler and more polished case for his conclusion than I have, but he also more clearly asserts that: either we (almost certainly) live in a simulation or such ‘ancestor-simulations’ just never get made.
UPDATE (Dec.11, 2012): Scientists at the University of Washington have set out to try and find the ‘signatures’ deep within physics that might tell us whether our universe is a simulation. Link.