The rehabilitation of reason is urgent because it is only through the proper use of reason that we can find our way out of the quagmires in which man… - Julian Baggini

This point is, in essence, the most important and overlooked one regarding the rationality of ethics. The traditional dispute between Kantians and sentimentalists rests on an assumption that to be rational, morality must be grounded on a priori principles of disinterested reason. This is false. If we understand what rationality means in an appropriately catholic way, we see that it it is a matter of providing reasons for belief and that the sources of these reasons are not confined to a priori principles of logical or scientific facts. Once we accept that, we can see that although the Kantian project of founding ethics on pure reason is doomed, reason is still at the very heart of morality.

Our obsession with our differences has created the impression that there is no common domain of rationality within which disagreements can be thrashed out. We just have a multiplicity of discourses and rationalisations to legitimise different interest groups. This is not just a criticism of those currents of thought broadly and loosely labelled postmodern. The enemies of postmodernism have set themselves up as the sole champions of reason – something made easier by their opponents’ willingness to relinquish the labels of rationality and reason. In so doing they too have contributed to the sense in which the intellectual sphere is too fragmented and divided along factional lines for any general dialogue to be possible. By dismissing large sections of the intellectual community as anti-rational, the anti-postmodernists have also contributed to the sense that it is pointless to seek to argue one’s case in the widest possible forum.

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?