But, I Don't Think is a science fiction short story by prolific author Randall Garrett.
A man called "The Guesser" is a Class Three member of a strict, hierarchical space-going society, that is fighting against another civilization they know only as "Misfits".
The Guesser has a talent for knowing where an enemy ship will be before even the on-board computers, and aiming a weapon to destroy it.
She has stolen the uniform of an Executive and wants the Guesser to wear it and take a ship to bring them both to a Misfit planet.
Reunited with his ship, he is told that he was waylaid by his subordinate, who wanted his job, but has failed to perform properly and been stripped of all his ranks.