To answer this requires knowledge of ‘child development, healthy emotional lives, healthy cognition and what is going to equip children to become hig… - Julian Baggini

Some may be surprised to have found that my defence of reason has been so eager to point out its limitations. With friends like me, you might wonder if reason needs enemies. But reason needs this kind of tough love. It cannot be treated like a child that needs unconditional support. Rather, it needs to be treated like an elite athlete that always needs to be pushed to work harder and improve, because otherwise nothing can be achieved. The most difficult issues we face often require us to go to the edge of reason, stretching its capacities to breaking point. To extend the training analogy, it would be a mistake only to praise it for what it does well almost effortlessly, such as analysing the formal logical validity of arguments or spotting contradictions. It needs also to pay attention to where it is naturally weaker, such as when it has to deal with ambiguity or premises that cannot be proven, and when it requires the careful use of judgement.

If it seems shocking to some that scientists are not cold computers but human beings with different preferences, dispositions, skills and temperaments then they must have a very strange idea of how people think. Science is indeed a rational pursuit par excellence. But it does violence to the notion of rationality if we pretend that it is not a complicated, somewhat messy capacity.

Many are now skeptical of Freud’s theory – and of psychoanalysis in general – but the broad idea that the unconscious is in the driving seat has become widely accepted and has been given empirical support by contemporary research in psychology. Experimental psychologists might be less convinced by the primacy of Freud’s eros and thanatos – the sex and death drives – but they have catalogued a large number of biases and distortions of thought that affect each and every one of us. They may have abandoned Freud’s specific ideas but they have only added to the general picture of human nature he painted in which we are not so much rational as rationalisers, using reason to make sense of our beliefs and actions after the event. Must we therefore accept that reason is a mere veneer for irrational impulses, or can can psychology justify giving rationality an important role in human thought and judgement?