Eric Greene points out how, in Star Trek, 'Spock reflected Kirk's intellect and McCoy embodied Kirk's emotions. Watching McCoy and Spock argue was like seeing Kirk's internal dialogue externalized.'
Similarly in Firefly the characters of Simon and Jayne are set in direct contrast. Simon is devoted to the protection of his sister, he has risked everything for her - in the episode Safe he is even willing to be burnt at the stake with her - Mal shows the same sort of loyalty to his ship and crew. Conversely, Jayne displays a practical self interest and is unable to understand acts of altruism. 'Jayne's strictly rational common sense and Simon's Quixotic and chivalric devotion established the two men as opposites and repeatedly led them to butt heads.'
Green continues: 'Zoe shares Mal's experience as a soldier, the primal bonds developed by comrades in arms, and understands his special relationship to Serenity Valley. Kaylee shares Mal's love of the ship, Inara his emotional guardedness and fear of intimacy; River, like Mal, has been interferred with and wounded by the Alliance. And Wash ... represents Mal's spirit of resistance to authority and is the one most likely to challenge Mal's orders. ... But while the rest of the crew tended to reflect Mal that is, Book reflected Mal that was, but is no more: Mal as a believer.'
After describing the opening scenes of the pilot episode Green writes: 'In a few concise gestures an entire arc was implied and understood. Mal believed once but no longer. While Book, a former sinner we may assume, now believed. It would seem that just as the defeat at Serenity Valley stripped Mal of his belief, something pushed the shadowy Book into the light. While belief in something larger disappointed Mal, that very belief may have saved Book. Thus, like the rest of the crew, Book reflected an aspect of Mal, but it was more of a reflection in the literal sense: a reverse image.' Greene, E, 'The Good Book' in Espenson, J (ed), Serenity Found: More Unauhorized essays on Joss Whedon's Firefly Universe, (Dallas, TX: Benbella Books, 2007) pp80-82.
I want to explore further what it is that brings people to accept faith and what leads them to reject it - knowing of course that there is no one simple/correct answer and that a lot of people today have lost faith in the church rather than in God.