These practices work regardless of your belief in them. What is known as the Law of Assumption, or Law of Attraction, is just one of the many universal laws. It states that the experiences of someone are a direct consequence of their beliefs and thoughts, because these are energy, and that energy seeks what is like it and brings it into manifestation. Thoughts, words and actions work together to attract, and thus create, your life. When these three are in harmony (pointed towards the same goal), the process is faster and easier. The Placebo Effect, as science knows it, is a consequence of the Law of Assumption (you belief that a substance is good for you, and thus it is).