The life of adults is regulated ultimately by laws, and if someone comes and hits you, you may expect (in a civilized country) that the person will be punished by law. Meanwhile, even in developed countries physical abuse has not been eradicated and poses a certain threat. So you can imagine the situation in backward countries where the people are accustomed to physical violence in the home and on the street.
Children adopt their beliefs initially from adults. Children believe in the infallibility of adults. For them adults are the source of all knowledge and all morality. Therefore it is obvious that if the children undergo physical violence, they will start to perceive it as something absolutely natural, right, fair, necessary, approved by the highest authority.
A simple conclusion follows: one must never use physical violence against children under any circumstances.
There is an addition to this rule, determined by the fact that children themselves sometimes start using physical violence under the influence of negative emotions or curiosity. In this case it is sometimes necessary to keep them from violence not only by persuasion, explanation, affection, but also by adequate but not excessive counter-violence. Such restraining violence under any circumstances must not be accompanied by aggression, anger, accusatory tone or facial expression; otherwise the violence will cease to be a deterrent and will become ordinary aggression.
In case children obstinately show antisocial aggressive behaviour, it is necessary to simulate for them those kinds of counter-violence and restrictions on their freedom that would apply to them if they were adults. Starting from the mildest forms with further gradual tightening in the event of need. I want to emphasize that in such cases as well physical violence is absolutely unacceptable.
One-time use of violence against children, who themselves physically abuse others, is acceptable only for educational purposes and, therefore, only when accompanied by explanation (that the violence is being used only for the child to understand how much it hurts, how physical pain is unpleasant) and only at the age when the child can understand these explanations.
In all other cases physical abuse of children is completely intolerable, because they would very quickly, almost instantly form an attitude to life in which physical violence is acceptable and even necessary. No slapping or spanking or flicking – nothing of what is almost universally considered normal. Nothing. No physical impact aimed at causing uncomfortable sensations to a child.