Many self-help books and self-help gurus teach that our beliefs create the world we live in as individuals and that changing our beliefs can change our world.  For example, if we always think of ourselfs as a poor person who always has to struggle to get by, than that is the world we will live in no matter how many opportunities exist to get out of it.  If we think of ourselves as being fat and unable to loose weight, it will be next to impossible for us to loose weight and, when we do, we probably gain it back quickly, unless we change our beliefs.  
    There is ample evidence that changing what we believe can make such changes in our personal world happen, whether we use creative visualization, writing down goals and plans, or other methods to change those beliefs.  What these programs never really explain is, why does it work?
    It works because the material word is a world of illusion.  That doesn't mean the material world isn't real, but rather, it isn't what it appears to be.  Like seeing magician David Copperfield and his assistant walk thought a spinning fan, turn to smoke, then pop out of a box in the audience unharmed.  The trick was real, but it wasn't what it appeared to be.  They didn't really walk through a spinning fan and the puff of smoke wasn't really Copperfield and his assistant.  The same kind of trickery is what the material world is all about, but few realize it.  It is only because matter is not the solid reality most of us believe it to be that we can change it with our minds, with our beliefs.  If it really was solid and real, we could not manipulate it in that way.  Just as we cannot change the spiritual world.  Which is why great spiritual teachers often say that the spiritual world is the only real world and the material world is not real.  What they mean is that it isn't at all what it appears to be.