First, the assumption that the person asking the question desires to lead a good moral life. Second, the following conclusion that if someone is moral, they will pursue the truth regardless of how helpful it is. By establishing these ideas, Lewis creates the need for finding a truth that will dictate a moral life. He then points out that no two ways of living, be it Materialism, Christianity, or Buddhism match up in all aspects of morality. Thus, only one can be true, and it is up to the person asking the question to decide upon the truest one, or else he is not the moral and good man he wants to be.
Another way of looking at this issue is to consider again the position of the person asking the question. If he is asking whether he can be good without Christianity, he is aware of Christianity. If he chooses not to investigate Christianity, it is not simply an accident, but a distinct choice to avoid Christianity for whatever reason the querier is in a state of “dishonest error” and ignorance. Lewis points out that, in his opinion, some men lived in a state of honest error and cannot be held responsible for it, but to knowingly avoid a potential truth is the real