system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How come our brain ( in all its power ) can very rarely recognize that its in a dream vs reality when there are no physical stimuli?
gpt
Sleep is very important to us. during sleep, parts of the brain shut down - one of which is the amygdala which controls inhibitions. That makes it harder for us to discern reality from fantasy. 

Another thing that happens when you sleep is that the hippocampus does a lot of memory sorting. That's when memories are encoded into your long-term memory. As you can imagine, this is *also* very important. 

And that's likely why dreaming happens in the first place. 

It's pretty important that this process be allowed to happen, so basically the brain puts the rest of you in Do Not Disturb mode. 

It's not that the brain lacks power to know we're dreaming. On the contrary, the brain *is* powerful enough to make you not interrupt the important stuff!