The prophecy spoke of the chosen one, destined to bring balance back to the force. Which would, if you choose to see it this way, imply there is fate and destiny. Which means there is a force (lack of a brain-thesaurus, no pun intended) at work setting all things into motion.

You could argue that the future is not directed by any sort of higher power, and that the 'prophecy' is only the result of the occasional Jedi with precognitive abilities. An argument could be had for this, but in the world of fantasy, by definition the event exists before the prophecy.

This is similar to the writings of Jedi Master Zurin Arctus, whose writings we are all familiar with - he wrote that "each event is "preceded by prophecy. But, without the hero, there is no event." The hero, in this case, could be interpreted many different ways. Is Anakin Skywalker truly The One prophesied to balance the universe? This is what Lucas, the God of Unnecessary Story-editing, would have us believe. Some believe Luke Skywalker the reason these events unfolded as they did. Could he not be the figure forseen by the Jedi of Old? If that argument is to be believed, you could say Leia had just as important a role in the events- she was responsible for setting in motion the events of A New Hope.

And what of R2-D2? He was not only present for every event, but freaking shot out of a ship in space like the supreme badass he is and landed next to Luke and Obi-Wan on some crummy desert with a womp-rat problem. And think back to Luke training with Yoda. He makes the mistake of using the word "try", which leads to the Yoda famously suggesting that there "is no try. Do it. Do iiiiiittt." In the back, you can hear R2-D2 say "Beep woooh beep blipblip beepitybeerooo". And I don't claim to know everything. I am certainly no expert on lore and fate in the Star Wars Galaxy, so disregard all of this