Since many varieties of self-deception are ineradicable and useful, it would be wise to be ambivalent about at least some of its forms.1 It is open-eyed ambivalence that acknowledges its own dualities rather than ordinary shifty vacillation that we need. To be sure, self-deception remains dangerous: sensible ambivalence should not relax vigilance against pretence and falsity, combating irrationality and obfuscation wherever they occur