Father's Day

Well sooooort of. I guess it's fairly predictable logic (in a sci fi time travelly way) that Pete killing himself would revert everything to normal. The Doctor getting the Tardis back with a mobile phone battery is one hell of a stretch, but thankfully he doesn't manage it. Question: why does Rose have to touch her past self to cause a paradox? Surely her very presence is a bit of a paradox in itself. Oh well.