“When reckoning with man without God, it doesn’t add up, and, when reckoning with the world, with the whole vast universe, without Him it doesn’t add up”. In his homely at Mass on the esplanade of Islinger Feld, the Pope wondered whether “our basic decision”, summarised in the statement of the Creed “we believe in God” – is “possible” and therefore “still reasonable today”. “Since the Enlightenment, at least part of science has painstakingly strived to look for an explanation of the world in which God may become unnecessary”, highlighted the Pontiff: “And so He should become unnecessary in our life as well. But every time it seemed to be nearly there it always became clear again: it doesn’t add up!”. Ultimately, the option is between the “Creating reason”, i.e. “the Spirit which actuates everything and triggers development”, and “Irrationality”, which “takes off every reason, strangely produces a cosmos ordered in a mathematical way as well as man, his reason”. The latter, though, objects the Pope, “would then be just an accidental result of evolution, and therefore, deep down, an unreasonable thing”. We Christians instead “believe that the source of this all is the eternal Word, it is Reason, not Irrationality”. “With this faith, we do not need to hide ourselves, we do not have to fear to be, with it, at a dead end”.