He presents three proofs. First he reviews recent neuroscience discoveries regarding the brain and the mind and the meaning of each. He then works through the arguments of philosophers such as Hegel, Kant and Schopenhauer. His third argument is a presupposional one, using the existence of moral values (the feeling of the way things "ought" to be) as a basis. (The supposition of dark matter and energy is an example of a presuppositional argument.)
D'Sousa ends with the practical considerations of believing in an afterlife (and not believing). What approach would make for a better situation for mankind? How do beliefs in an afterlife, or lack of it, impact society?
D'Sousa concludes, "Even if we are unsure whether there is life after death, reason suggests that we should act as if there is." (P. 212) "...[T]here is strong evidence that belief in life after death makes your life better and also makes you a better person..." (P. 216)