"We all could just be really bad at shedding unconscious beliefs we form from peer modeling. I mean how many of us have seen a person legitimately defy gravity? It could be an intense form of massive groupthink on a planetary scale. Maybe we just need to focus our chi, our ki, our psynergy, and then we can transcend the limitations we see before us that form when we're mere babies who only know the world that was shown to us. For all we know we could be being weighed down by excess Thetans."
There is the Global Consciousness Project: http://global-mind.org/
it seems to prove that global state of mind has physical effects on the world. but they are much smaller then gravity
And gravity seems to have existed before humanity was there to have faith in it.
I think its possible that people can influence matter only with their minds, but there is too little data to take this into real account, for now. However it is a good speculation point of view, mainly due to the Global Consciousness Project's results, which are undeniable link between people's state of mind and their machines random generation(they set up machines that generate random numbers all over the world and they work 24/7, and when there are big events like 9/11 or big football games, the numbers become biased and not random).