i think they only started offering it a couple of years ago so I just missed out
but i think it's literally what BLIT2014 said - it's under philosophy and students would probably be working on thinking laterally and developing more profound strains of thought and their own ideas rather than just being spoonfed or rote learning
also the teacher for it is super intelligent and she also teaches history extension which is heavily underpinned by critical thinking so she really knows her stuff