The only thing I feel certain of is that hitting children or abusing them is a sad unnecessary practice. Adults need the wisdom and sense to handle problems with logic and words. Physical violence is simply bullying and using superior size and strength, which is irrelevant in the modern world and which predisposes your children to violent behaviors.
What makes you feel certain of this? I may be wrong, but a majority of human history seems to point to (roughly) "spanking is ok, anything more is not". Children do not understand logic the same as adults.
The adult domestic violence was also accepted a lot.