Some critics of religion see having faith as being childish. But John Gray argues that believing that human beings are rational is more childish than believing in religion. The belief in the power of reason to improve humankind rests on childishly simple ideas he says. One of the commonest is that history's crimes are mistakes that can be avoided as we gain greater knowledge. But if history teaches us anything, Grey asserts, it's that behaviours and attitudes like cruelty and hatred are permanent human flaws. To imagine that we can become more rational is an example of magical thinking and an expression of the belief in the omnipotence of the human will that psychoanalysts identify as the fundamental infantile fantasy. John Gray believes that we'd all be better off if we saw ourselves as we are: intermittently and only ever partly rational creatures, who never really grow up.