Energy is conserved.
Recent scientific studies have proven that people can influence matter through conscious intent (just watched new findings about this on Tuesday actually).
Theory says it works like this: You (with or without others) mentally create something (which starts as so-called "Consciousness Units" or CU's), which make up so-called Energy Units (or EU's), which finally make up the smallest subatomic particles and, eventually, matter.
E = mc
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Then there's my thoughts. We are playing in one gigantic first-person game/reality/experience/etc. Everyone chooses a role before starting and, like any really good actor, attempts to forget anything else known before except for what's required for the role (needless to say, some of these "forgotten" items seep into our minds and really toss things around!). The goal is to learn and the game can definitely be played multiple times. Chew on that!