Your review of Backsliding: Understanding Weakness of Will ("Just one more wafer-thin mint?", Books, 16 August) should have recast the problem as one of epistemology.
How can Jack, struggling in the third year of an obscure media studies course at a mediocre and poorly staffed university, possibly know that two hours of early evening revision are going to improve his career prospects one iota?
Neil Richardson, Kirkheaton