From the introduction: Psionics are the manipulation of the world through mental power, as opposed to magic. Psions draw their power from their minds, their bodies, invoking and unlocking unleashed mental energy, as opposed to magic, which invokes the world through math, and Invokers, who use words to manipulate the world. Psionics is split into seven separate focuses, each with it's own definitive way of producing effects from the mental energy that exist within them.