Eliezer Yudkowsky. Harry Potter and the methods of rationality (№ 390246)

Most interesting is that he had to agree with his father. No one has ever seen any evidence of the reality of magic, and the mother indicated that there is a whole magical world. How can you keep a secret? Also with the help of magic? Rather suspicious explanation.
Case the idea is simple: mom or joking, or lying, or crazy, in ascending order of awfulness. If she sent the letter, it explains how it got in the mailbox with no postage. In the end, the craziness of much, much more likely than the universe that contains magic.
But still, some part of Harry was utterly convinced that magic is real. This feeling arose at the very moment when he saw a letter supposedly from Hogwarts, School of Witchcraft and Wizardry.
Pulled a face and Harry rubbed his forehead. Do not trust your thoughts, it was written in one book.
But this strange belief... it's like He knew in advance that the Professor Hogwarts in fact, appears on their doorstep, will wave his wand and create magic. This conviction was not trying to protect themselves from refutation: not looking for excuses in advance in case if any Professor won't come, or will come, but will show only the trick with the spoon bending.