Does this make sense to you?

1 - Current science does not explain why our body still functioning while we sleep. There is a high state of subconsciousness operates our body that we're not aware of. Certainly, I do not know the nitty gritty details of how my body works, eg how many beats my heart must do, which arteries should receive which amount of blood, etc. For that, I know our conscious state is limited. As for how to expand it and why, no idea. We're such destructive creatures as we are right now, no need for more capacity.

2 - We "assumed" to be truly alone in the universe because we cannot find anyone else, nor we have the capacity to search far and wide for other "living" beings. It's curiosity that forces us to seek the unknown. Also, being the first to find something adds to that madness. Even here, people tried to have "first reply" to certain thread.

3 - Equilibrium.

PS: those are what I think. I am not saying they're technically correct.

Yeah... no. Science can exactly explain how we function while we sleep - we have subconscous areas of our brain that perform vital homeostatic functions while we sleep, just like while we're awake. Ever heard of the hypothalmus?