Well yes and no. It works as a psychological tool no different than an illusion or mind trick.
Pardon: phrasing it this way - because of the "bah humbug" subtexts these terms have in our culture - creates exactly the kind of trivialization I object to. The ability to do this is sacred and magical to me.
If you believe in something hard enough it will in fact come back on you in a pysical sense. However this doesn't hold true to ANY divine intervention or mystical power. So it works but not in any way a believer would assume it to.
You might want to be a little more careful when making statements about what "believers" would assume. I, personally, have made no such assumptions, though I'll grant there's a chance I don't fit into your mold of what a "believer" is. :slap: