It isn't a question of belief. Magick* is a fact or it isn't; only by testing it for oneself can one resolve the question to her or his own satisfaction. In the Memories section of this journal (linked on the userinfo page) I have saved a number of essays on this and related topics, one of which ("Emergency Magick for the Non-Magician") includes a basic test on the subject that anyone can try.
Nothing I'm about to say, then, is intended to persuade anybody else to believe anything at all. Useful** (even unavoidable***) as "belief" in some senses can be, in many ways belief is the chief enemy of humanity: is the deliberate refusal to learn, and test, and come to understand.
Worse yet, belief is far more common than we realize: many of our most cherished "facts" are beliefs, and false ones at that. The vast majority of what passes for science is premised at least in part on fictions****, which themselves prevent advances far more stunning than we've seen heretofore. So long as these fictions persist, humanity will be awash in false dichotomies, most especially the conflict between "science" and "religion"...each perspective blinded, by its own false premises, from seeing the crucial facts offered by the other. Recognizing this, Aleister Crowley gave his initiatory system -- "Scientific Illuminism" -- the motto:
"THE METHOD OF SCIENCE -- THE AIM OF RELIGION."
Every time I try to write about these things here, I have to fight the temptation to rewrite my Student Handbook***** in LJ form. Instead, why don't I clam up now, and let you -- yes, YOU, anyone reading this -- ask what you're interested in asking, if anything?
Yep, think thass what I'll do.
93 93/93 -- AJ
* And Initiation. Magick is a learned skill (based on the conscious use of unconscious, but universal, processes); Initiation to Mastery is a personal development, largely a matter of resolving one's internal contradictions. Each can help the other, but they're distinct.
** Initiation must act upon our beliefs, many of which can help us a lot. At first.
*** Think "provisional assent, while retaining one's skepticism." This is true not only in AC's sense in the first three paragraphs of "Liber O"; it's true in every department of life. Cogito, ergo sum is (of course) the maximum, not minimum, of what we know for a fact.
**** One in particular: the belief in sentient matter.
***** Copies still available, natch. ;)