[gliese1337]

That question is answered by theodicy- the philosophical field of justifying God's dealings with the universe. I recommend C.S. Lewis's _The Problem of Pain_. The short version is that if you give people free will, then there is a risk that they will try to hurt each other; if you always intervene to ensure that they can't hurt each other, then their free will is worthless; and if they don't have free will, then what's the point of them living?

Now as I said, that's the short version, and in such drastically abbreviated form the argument has holes you could drive a humvee through. An alternate explanation is that the creators of the simulation simply don't care about us at all, and we and our problems have nothing to do with its purpose. One might also ask, if the creators do care about us after all, why didn't they just make everyone morally perfect so they wouldn't freely hurt each other? In which case me-with-my-theologian-hat would say "maybe a life of pain is the very process by which morally perfect people are created". But theodicy is a very large field which I cannot adequately summarize in this post, so if you want real answers, just start with that book.

[wladimir]

I sometimes envisage the simulation as the random by-product of some other computation. That we exist in the noise, the margins of some extremely large (maybe "game-of-life"-like) computation. The runners of the computer computation don't know what is happening at our level, they just see the underlying binary representation and the eventual result. There can be a large stack of emergent patterns, from the bottom-most jumbling of zeros and ones to quarks and eventually atoms and molecules. Even if they are looking at molecular level they would have no idea that anything alive and conscious and suffering is in there. Just funny moving patterns! How could they recognize a completely alien ecology running at arbitrary speed?

A somewhat scary thought.