system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can one prove that the world outside one's consciousness is not non-existent and that other beings with similar consciousness levels exist?
gpt
One can't. 

There is no direct contact with the external that does not go through the processing of your brain. Everything you experience is a reinterpretation - a model if you will - built by your brain. 

Of course, that's also being a bit presumptous because the only reason we think there **is** such a thing as a brain is that we are getting that information from the 'outside' which is being reinterpreted by the model...

Kinda circular.

The only rational answer to this question is that it really doesn't matter. You have a choice to believe that what your mind interprets as external phenomena is real or not. If you do not believe it is real then there is no point in... well, being alive at all really; so better to just come down on the sensible side of the fence - presume the unprovable external reality - and get on with more important things like eating bacon, reading books and having sex.