You [i]can[/i] swim. Its hardwired into your survival instincts, of course that holds merit as long as you don't start splashing around like a retarded magikarp. i recall reading an article for my Criminal Investigation class that most (circa 90% can't remember exact figures) drownings occur either due to exhaustion caused by the individuals own idiotic flailing or an injury which prevents the instincts to kick in. If you dont believe me hold your head under water, and try as you may, you will not be able to drown yourself due to your bodies own instincts, same principle applies here.