Up until now, Gohan had tried to be the perfect scholar. A pretty fine scholar he was.
He had grown up in a world with martial arts and super powers, nonetheless, he liked books and the peace of the scholar life.
He thought it was peace. That was until Golden Freeza appeared. He could do nothing but buy time until Goku came. He then wondered if he hadn't chosen the wrong profession. He was told he had the gift of being a Super Sayan Human hybrid and that this conferred him the potential to be better at martial arts, or at least power, than both Goku and Vegeta. However, he had none of their passion for martial arts. Almost none.
The apathy easily killed his attempts at training.
It wasn't until he read "Logic, Bayesians and the Rational Utilitarian Ethics", that he had the true epiphany.
Taking a pause from his studies of the Spanish language, he read this book. Gohan began to take an interest in linguistics. How interesting was it that even the dragons had their own language? But he paused it for this book.
He was so amazed by the book that he even looked the references. "Carl Sagan and the Cosmos".
He saw some analogy about a dragon and a guy claiming he had one. The average human, Gohan thought, had never seen a dragon. Only a fraction of them knew about the myth of the Dragon Balls. Dinosaurs, sure, were common knowledge.
He was reminded of a part of the previous book that pointed this out. You sometimes have to reason with imperfect information. It would be reasonable to even doubt that dragons existed, if he hadn't seen them and there wasn't any evidence. Sure, it turns out to be wrong, but we don't always have perfect information.
Moreso if the other guy started to make up excuses for why the dragon isn't there. You'd doubt the guy.
"Like, just summon it with the dragon balls." Gohan thought. Then he'd see the dragon.
But the other guy was clearly making up excuses. Likely, he had no dragon.
It was then that Gohan's epiphany happened.
Was he being by default rational just because he is a scholar, when in this world constant threats appeared requiring martial artists to beat them? Shouldn't he, being a semi-Sayan Human hybrid, who possesses such potential, be more rational by training his fighting abilities, despite it not being "scholarly"?
It was then that he became... Super Rational Gohan.