Last time I considered the Christian claim that reason and logic can only derive from God, and that non-believers’ use of them is nothing more than a illicit hijacking of powers supplied by the God they deny. Why is it important to modern day Christians to attribute reason to their God? After all, the bible only ever speaks disparagingly of reason. It is, it says, the path to self-delusion; Proverbs 3.5 warns ‘trust not in your own understanding,’ while faith, according to Paul far surpasses the limitations of reason and rationality. More than this, as I discuss here, the God of the bible is far from reasonable and logical himself. His response to every issue is the death penalty, mass murder and blood sacrifice.

According to Christians, human reasoning makes no sense if it is ‘merely’ the product of evolution. A random and undirected process cannot produce a reliable rationality on its own. Naturally, they are never entirely clear why this is the case; evolution has, after all, led to other distinctly human characteristics on which we regularly depend, imperfect though they may be: language, memory, social bonding and creativity among them.

However, having singled out reason and dismissed evolution as its cause, Christians then jump to the conclusion that the human capacity to think must come from God. According to Tim Keller, rationality is a ‘clue’, planted in every human being, to God’s existence.* It has evidently never occured to Keller that, by the same token, the human capacity for unbounded irrationality is likewise a ‘clue’ to the non-existence of any rational deity.

Human reasoning – and there’s no other kind – is, like every other evolved characteristic, flawed. It is only as secure as the premise from which it proceeds. Get that wrong, by adopting a premise with an insufficiency of evidence (such as ‘God is a God of Reason’) and human cognition will only ever abandon us in the blind alley of faith.

*The Reason For God, p141