A fortnight had passed since Harry had checked out the Star Wars novels, and when he wasn't seeing to his aunt's garden, or cleaning up after his slob of a cousin, he was in his cupboard with a torch/flashlight pilfered from Dudley's second bedroom, making steady progress through Skywalker's crusade against his family's killers. The Dursleys would have loudly objected to his doing anything vaguely intellectual, so he made sure they never found out about his (oh horror of horrors) reading. Their standard for what "normal" boys should do was their son, who was about as uncivilized as the tribe in Lord of the Flies.
Of all the days for Dudley to begin building up such a tribe ("making friends", according to the willfully blind Aunt Petunia), it had to be the day when the school library was closed for renovations! Consequently, rather than learning how Luke would escape Dagobah with a crashed ship, Harry was fleeing from a pack of local savages, and only partially succeeding.
He realized he was being corralled into the alleyway behind the kitchens, and that he had no alternative but to play along. Fortunately, there was a line of trash bins available as a hiding place, though that seemed too obvious for even Dudley to miss, now that he thought about it.
His subconscious mind, however, provided an interesting solution to his problem. Right as he vaulted over the trash bin, he found himself on the roof above the alleyway.
It might have been the wind, except then he would have traversed the intermediary space between the ground and the roof. the only other explanation was that this was another Unexplainable Event, like when his hair had grown back overnight from the terrible haircut Petunia had inflicted on him. As explanations went, this was lacking. So he, again, tried to find what all these incidents had in common, other than them happening to him.
The only explanation that kept coming up was "magic", but Vernon and Petunia both vehemently insisted that magic didn't exist. On further reflection, Harry concluded that since those two...people...also said Dudley was what every respectable boy should aspire to be, their word was at best questionable.
The aforementioned paragon of boys everywhere was now throwing a small tantrum in the alley below, until Gordon suggested they find some other innocent to harass.
Even discounting the word of his guardians, however, Harry was reluctant to attribute all these incidents to "that which cannot be understood" as the library's dictionary had said about the etymology of the word "magic". It just seemed too much of an intellectual cop-out. The thought which had been percolating in his head since he'd finished Matilda now had considerably more fuel on which to feed. He began connecting the dots in his mind, with the idea of a "mystical energy field controlling everything" at the forefront of his thoughts. As he couldn't find a way down from the roof, he figured he might as well pass time trying to see if such a thing actually did exist, and if it might help him control these incidents. He settled against a chimney stack and closed his eyes, attempting to meditate.
Unfortunately, just as he felt he was about to make a breakthrough, the bell rang signaling the end of recess. And he was still up on the roof. With no way to get back to class. At least he'd thwarted Dudley's latest attempt to beat him bloody.