What evidence is there for us being in a simulation?

Bostrom's trilemma is as follows:

1. No civilization will reach a level of technological maturity capable of producing simulated realities.
2. No civilization reaching aforementioned technological status will produce a significant number of simulated realities, for any of a number of reasons, such as diversion of computational processing power for other tasks, ethical considerations of holding entities captive in simulated realities, etc.
3. Any entities with our general set of experiences are almost certainly living in a simulation.

The disjunct made up of the three statements seems fairly solid and many of us have lowish priors for the first two disjuncts, and so assign a highish probability to the third disjunct.

I've never heard of humans wanting to "simulate" history.

• I want to simulate history.
• I'm a human.
• Therefore, some humans want to simulate history.

Civilization doesn't play even remotely like a simulator and never claimed to be. The information equivalent to an entire world would have to be converted into data storage for such a project and what possible motive could there be for that? I'll follow Occam's Razor on this one- the more assumptions you make, the more likely you are to be wrong unless you have some sort of evidence.

The rest of your comment seems incredibly...uninformed of the relevant literature, to say the least.

Please read the referenced articles by Bostrom. See simulation-argument.com

What evidence is there for us being in a simulation? I've never heard of humans wanting to "simulate" history. Civilization doesn't play even remotely like a simulator and never claimed to be. The information equivalent to an entire world would have to be converted into data storage for such a project and what possible motive could there be for that? I'll follow Occam's Razor on this one- the more assumptions you make, the more likely you are to be wrong unless you have some sort of evidence.

This argument is called the Doomsday Argument. It has been discussed several times around these parts (e.g. here)

In a technical sense, the issue resolves around how you think self-sampling should be understood. You might consider looking up the "Sleeping Beauty" problem for more discussion of that point.

In a non-technical sense, there's what might be called the "reference-class problem." On the one hand, the number of people in existence has constantly been increasing over time. On the other, the number of interconnected civilizations seems to be dropping (after the widespread adoption of the internet, one could argue that the number of distinct civilizations currently in existence can be counted on one's fingers and toes). Figuring out the correct reference class has profound effects on the conclusions one reaches using this kind of reasoning.

Here's an interesting problem: why do we live in this era? Imagine the people that lived before we migrated out of Africa; when the human population was less than 10,000. What were the odds of being one of those people? At least less than winning the lottery. So we can conclude that the likelihood of existing in a specific era is proportional to the amount of consciousness in existence during that time period.

This presents a major problem for a technological singularity as the odds of living before the singularity turned all matter in the universe into consciousness are virtually nil. So there will be no singularity, and it's almost frightening to imagine what we can conclude from this for our future.