Pharmacist: A large study of people aged 65 -- 81 and suffering from insomnia showed that most of insomnia' s symptoms are substantially alleviated by ingesting melatonin, a hormone produced by the pineal gland, which plays a role in the regulation of the body' s biological clock. Thus, the recent claims made by manufacturers of melatonin supplements that the pineal gland produces less melatonin as it ages are evidently correct. The pharmacist's argument is flawed in that it ['infers from the effect of an action that the action is intended to produce that effect', 'depends on using two different meanings for the same term to draw its conclusion', 'confuses an effect of a phenomenon with its cause', 'relies on a sample that is unrepresentative']