It comes down to: physical phenomena _are_. If you do something and it has a given effect, then you've got something to investigate. Next job is to find why and how it happens. For acupuncture/herbal medicine, it may be psychosomatic; alternatively it may be some effect in the human body which we don't yet understand. Maybe we don't yet have the skills or the technology to find how it works - to some extent, medicine still relies on prayer, just hoping that the body sorts it out itself! - but one day we may do. Incidentally, try this for a funny take on that.

Astrology is rather too subjective, though. If it said "This is going to happen at this time on this day", then it's provable. If it just says "Something bad's going to happen to you next year", well of course! The human brain is rather too good at pattern-matching, so after the event it's easy to pick evidence which matches the conclusions you want to draw.

Aliens, ESP, etc - well, if they happen, then prove it. Science is the art of putting formulae to physical phenomena (ooh, alliteration :-) so if you can show it happening and produce some statistics on how well it works (eg. ranges for ESP, through walls, etc), then that's good enough for any scientist. There's no need to say HOW it works - Faraday hadn't a clue about electrons and Newton didn't know relativity, but it didn't stop them producing a good first draft of what was going on. Conversely, if you can't demonstrate it, provide proof of it or give statistics on properly-run experiments, chances are you're peddling snake-oil and should be tarred, feathered and run out of town.

Trouble is, belief _cannot_ by definition be logical. Suppose you believed in Father Christmas and the Easter Bunny - really believed, like religiously. If we told you that it was just your parents, a true believer wouldn't change their mind. After all, they've got proof that they do exist, from the presents and Easter eggs! :-) Crop circles are a prime example of this. "Maybe everyone else's crop circles were fakes, but mine are real!" translates very well to "Maybe everyone else's parents put out Easter eggs, but the Easter Bunny did do mine!" Prove that the crop circle was made by an alien spaceship, not 2 blokes with a plank and a measuring tape (or produce a picture of a rabbit supplying chocolate eggs), and you're credible and should go and publish in "Nature". Find a crop circle which _probably_ couldn't have been made by 2 blokes with a plank, and you've got a good working hypothesis to try and find support for. Say that you "feel the energy, man" when it's been shown without doubt (complete with impartial photographic evidence) that the crop circle was done by 2 blokes with a plank, and you're merely a credulous kook.

Grab.