Free Will vs. Alternative Realities

The Devil took the form of a drinks machine last week as I sat at lunch. I'm sure that none of my fellow diners noticed it's transformation from inanimate object to darkness incarnate, but I happened to look up just as the thought entered my head: "I quite fancy a can of diet coke."

What?! Who said that? Dammit, that drinks machine must be possessed by Satan!

Intellectually speaking I did not fancy a can of diet coke. Caffeine doesn't agree with me, and I've read enough horrendous things about phenylalanine to put me off it for life. So where had this thought come from?

Why was I unable to override that impulse with that knowledge of what is good for me? Was it my destiny to drink that can? Do I actually have any control over myself whatsoever, or are all my actions dictated to me through circumstance?

Well that's all very perplexing and I'm sure that Gurdjieff would tell me that I am lucky to even be conscious enough to realise I'm an automatic machine. But what's really baking my noodle today is the fact that Free Will isn't compatible with Alternate Realities.

In most mainstream science fiction and (I'm told) recent quantum mechanics theory, the existence of parallel dimensions is accepted. At each moment, or perhaps each conscious decision made, the universe splits so that every possible outcome gets played out. It makes sense really, if you were God and you wanted to create something to see what it did, why would you limit it to one outcome? Wouldn't you write the equation and then plug in every possible combination of values?

So what about those decisions that aren't conscious - that are handed to us wholesale, already formed? Is that destiny, or is someone else calling the shots?

But - I remember from my quantum mechanics reading - it's the presence of a conscious observer that collapses the probability waveform, that causes a single path to be selected. Perhaps while a person may exist in a billion alternate realities, they're only a conscious observer in one?