I think I’d consider the eponymous hero of Stephen R. Donaldson’s Chronicles of Thomas Covenant a rationalist character—at least in the first book, Lord Foul’s Bane. Covenant is struck by a car and wakes up in a fantasy world. Accordingly, he refuses to believe it is real, and most of his decisions stem from that, including a rather horrible one that has far-reaching consequences throughout the first series. What compounds the whole situation is his debilitating leprosy. Donaldson created a very plausible depiction of a real person stranded in a fantastic world, and while Covenant is not entirely rational, he does live by a very strict methodology.
Isaac Asimov was also one for creating rational heroes, but much of his work is quite dated (and his female characters often leave much to be desired). Hari Seldon is a pleasantly rational character, though. The ultimate author of rational heroes is Ayn Rand, of course, but her characters are, as you say, about being rational.
I think I’d consider the eponymous hero of Stephen R. Donaldson’s Chronicles of Thomas Covenant a rationalist character—at least in the first book, Lord Foul’s Bane. Covenant is struck by a car and wakes up in a fantasy world. Accordingly, he refuses to believe it is real, and most of his decisions stem from that, including a rather horrible one that has far-reaching consequences throughout the first series. What compounds the whole situation is his debilitating leprosy. Donaldson created a very plausible depiction of a real person stranded in a fantastic world, and while Covenant is not entirely rational, he does live by a very strict methodology.
Isaac Asimov was also one for creating rational heroes, but much of his work is quite dated (and his female characters often leave much to be desired). Hari Seldon is a pleasantly rational character, though. The ultimate author of rational heroes is Ayn Rand, of course, but her characters are, as you say, about being rational.