I've read about the vipassana technique taught by Goenka. It's a body scan technique, as you know. Do you think that calmly observing bodily sensations can really lead to a change in a person's psychological conditioning? I think the theory is that people react more to bodily sensations than they realize and that the vipassana technique can be used to stop those reactions, leading to a calmer, more peaceful life. I'm just not sure that this is true. That is really my problem right now, if I thought it was true then I would probably be at a retreat right now.
Not being sure is not a problem. Actually, it is a very good, honest place to start. And it sounds like you are open-minded - if you were sure the theory weren't
true, then you wouldn't even be considering the retreat. The point of the retreat is to discover if it is true. The great thing about Buddhist practice is it's about experience, not about believing in theories - I think that is what draws you to it.
I can't say I know exactly how it works, BUT - I can tell you that I went into that retreat very depressed, and through the process I tasted that happiness is possible, and totally unrelated to conditions outside myself.
At Goenka's retreats, they don't ask you to believe anything or accept any theories. Mainly, they give you simple instructions and ask you to practice them to the best of your ability for ten days. Then you are in a better position to formulate opinions.
Really, you have nothing to lose by trying it out. If you don't give it a chance, you will always wonder about it. . . and if you try it and find no value, you never have to try it again. But at least you will know it's not for you.