“It wasn't that Harry had gone down the wrong path, it wasn't that the road to sanity lay somewhere outside of science. But reading science papers hadn't been enough. All the cognitive psychology papers about known bugs in the human brain and so on had helped, but they hadn't been sufficient. He'd failed to reach what Harry was starting to realise was a shockingly high standard of being so incredibly, unbelievably rational that you actually started to get things right,as opposed to having a handy language in which to describe afterwards everything you'd just done wrong. Harry could look back now and apply ideas like 'motivated cognition' to see where he'd gone astray over the last year. That counted for something, when it came to being saner in the future. That was better than having no idea what he'd done wrong. But that wasn't yet being the person who could pass through Time's narrow keyhole, the adult form whose possibility Dumbledore had been instructed by seers to create.”