I think Dawkins is a smart guy, but he is so devoted to science that he fails to identify those areas of science that aren’t set in stone. For instance, there have been many, many studies on the mind’s ability to control things in the body. Placebo effects are one example, controlling allergic responses is another. But science doesn’t fully understand how that happens. Stress’ impact on a person’s health is another example. Science recognizes the statistical impact…high stress people frequently have a litany of health issues….but they don’t fully understand why mental or emotional stress impact a person’s physical health. Spiritual healing is nothing more than a way to try triggering these mental conditions that might help your body heal itself. It isn’t scientific and it is a shot in the dark, but that is what it is trying to do. Now rain triggering chronic pains may have a physical aspect that is at play. Rain happens when barometric pressure drops. You are now changing a physical parameter on the body. Same with certain “healing waters”. You are either soaking in a liquid that is at a different temperature or consuming a liquid that has certain chemical properties that may be beneficial for some physiological issues.