The answers
1 - So..........are thoughts things?
2 - Can they and do they affect our immediate environment?
3 - What IS the power of positive thinking?
1 - No
2 - Absolutely they do not (assuming that means external to self)
3 - Much research has been done on the placebo effect and the like. Positive thinking can have a beneficial effect on the biology of the individual. Plus, it's a key ingredient in personal business success.
-p (just think, all this without resorting to New Age tripe)