The human mind is about as persuable as a handfull of water, and on that note so are our perceptions. For example when your a child and you think that someday the earth will run out of oxygen (this is acually what i thought would happen when i was about 4) but one day somebody else tells you that your idea is wrong and that plants replenish our supply of oxygen, you automatically change your way of thinking to ocomidate somebodys else's. Even though your idea was wrong it was true for your mind, and in a small way your world, your reality was different from everybody else's. but thats just a small scale example, another would be to take into account the religous zealtos of our world, they cure people on a day to day basis, but only for true believers, but as soon as a skeptic walks up to be healed it fails, why? Because they hold different perceptions and therefore different truths and different realitys. The same goes for medival history, druids have tales of people transforming into animals, and beasts of nature, there might be some truth behind this, because they believed 100% that thier gods would allow them to do this they were able to do so, Lets take jesus into account he believed 100% that he was the son of god and this allowed him to walk on water, turn water to wine, and raise from the dead, and so on and so forth. And because he had his mind convinced his reality changed, our world, our reality is completely dependant on our mind, but today we arnt able to do these things, because we are programed from day one out of the womb, that not everything is possible and that everything has to follow a strict set of rules. And this kind of thinking might be passed down genetically as well, the same way animal instinct is and natures niches. But in short we control what happens to this world, we control our mind and therefore our reality.