Have you ever had a dream where everything seems perfectly normal, but after you wake up you realize that the school that you were in was also a hospital and also the people in your dream kept on showing up in different roles? Or some other crazy nonsense that seemed perfectly acceptable during your dream but until waking up you realized it was not a cohesive reality.
It's very difficult to determine that in a dream, but a thought occurred to me recently, what if reality as we know it is full of inconsistencies but our brains are just machines that make sense out of any data that comes its way and forces it into a coherent reality? We would have no idea we were in some irrational state.
This may seem far-fetched but the brain can do some pretty crazy things. Have you ever looked at that invisible gorilla video where you have to pay attention to the basketball and then it asks you if you saw the gorilla? Only when you replay the video do you realize it had been there this whole time and you didn't see it at all. Our minds are very selective about what they view, and they can literally alter the way we see the world.
Now, of course I don't really believe that's what's happening but it is interesting that there's no way to prove that it's not the case. We know that the world that we see is actually a model that's constructed inside of our brain. There's no such thing as color or sound just vibrations and wavelengths of light but our brain takes that input in constructs a model of the world based on the input it's getting from your senses. We would never know if there were huge inconsistencies that it just decides not to model because it's not beneficial to our survival to have knowledge of these inconsistencies in reality.