What a delight Neptune is, with his glorious, undermining illusions. A few months ago, somebody asked me to look at the case of an aging relative who was becoming ‘confused and forgetful’. We talked about it for a while, science, in the form of a kindly, but ultimately noncommittal doctor had no answer to the problem, nor any advice it seemed, except to “monitor the situation”. The fear was, naturally enough, Alzheimer’s.