Solipsism is the view or theory that The Self is all that can be known to exist.
You can only experience your conscious perspective subjectively, whether you are dreaming or manifesting imagery with your imagination – you perceive this reality only through your eyes.
Because you have the ability to create imagery in your mind just as vivid as you do when you actually experience it in reality, there is no way to definitively prove you didn’t create the observable universe mentally in the first place.
You can recreate the voice, look, movement, smell and feel of a person you haven’t seen in years instantly using your mind.
You can also create objects and people that don’t exist and give them unique characteristics in realistic situations with no effort mentally.
Lucid dreaming, astral projections, and visualizations are all prime examples of you materializing “real” experiences in your head!
You can’t prove you’re not God
and neither can I.