In this part of Collier’s book; we are informed that good fortune, health, sickness, etcetera, all reside inside us, rather than outside ourselves. The world is our mirror. This means that what is within us is reflected about us in reality.
Because Thought is the source behind all our life experiences; if you think you are week you will be week. If you think that you are strong you will be strong. If we are prone to think negatively about everything; this tends to make a body look worse than it would be if it were inhabited by a positive thinker.
There is no evil, just the absence of good. There is no darkness, only the absence of light. So, by constantly practicing looking forward to the bigger and better things in life, you will have better chances of achieving all that you desire.