Linda:
Personal Hygiene — Where water is available, washing one's bottom with water is absolutely the best and cleanest way. In contrast, pushing paper around and around never cleans one's bottom completely. Notice how we are always so much cleaner after bathing even if just a sponge or towel bath — versus merely "tissuing" ourselves?
A second way of looking at it — if you consider how absolutely intricate are our water filters — the notion that a few pieces of tissue can somehow form an effective barrier between our hands and our bottoms is a complete figment of our imagination (and cultural tradition)! That's why our parents, school teachers, etc. always harped at us to wash our hands afterwards! TP offers no protection — and the "eeeww" factor of not using TP is really just cultural.
Wash with water, then sanitize our hands, really is the most hygenic. And with just a few practices to get the hang of it, you DON'T need copious quantities of water either!
Environmental Impact The non-usage of TP in the wilds can only be a good thing for our environment. There is no need to use leaves or rocks or to smear stuff around. Just dig a proper hole (6 inches or so) sufficiently faraway from trail / water sources — do our deposit — wash with water — cover hole — and sanitize — and we are done. Nothing to pack in — or out!
This is truly one area where leaving something at home is actually a PLUS! I just wish more hikers can see outside their 'cultural box'.

