physical abuse doesn't teach that the action is wrong it teaches the action is wrong in your presence. It also teaches action X = beating. This is likely not what you want to teach. As this is mostly untrue, the world doesn't often punish crime with physical abuse and many think this is because we have moved on from physical abuse. My biggest issue is that if you can't explain why something is wrong than perhaps the action isn't wrong at all and you are in no position to push your authority on another. If your child is to young to explain why it is wrong than they are likely too young to understand the concepts of right and wrong and thus using any kind of abuse to teach children is nothing short of indoctrination. This stops morals from developing. To assume you can teach your morals to a child is fine, however teaching through explanation of wrong allows the child to willingly agree and hold better morals for it or choose to deny and the world can move on morally. the role of a parent is not to enforce their morals but best prepare heir child for a world where they can have their own morals, in the hope,they will be better than yours.