Ever since Dr. Benjamin Spock rolled out his psychobabble approach to parenting in 1946, generations have been adversely affected by this so called "spare the rod" idea. I think if parents really cared about their children, it might not be so bad to apply the "belt of wisdom" to the " seat of knowledge". In fact, we would have far more respect for authority today if kids realized there were consequences to their actions, be they good or bad.
It's a fine line. It definitely depends on the child and the situation.
My dad was pretty fierce with me, what would be considered abuse by todays standards for sure. The odd spanking, but the hard backhand to the face when I didn't even know why was most emotionally and psychologically the worst.
If you want to lay out punishment, you had better crystal clear as to why and the expectations. I would shake when I heard my dad come home from work every single day as a kid. He might never know this, but he had to know it affected me.
If I were being self aware, I believe I am an upstanding adult and particularly fearless in the face of a perceived wrong. Probably to the point from an evolutionary standpoint of it being a gene that should be in regression, hah. When the cards are dealt against you from birth and it's one battle after another, you go one way or another. Better me to be headstrong on principle than a career criminal.
Here is where it becomes grey,
adults today are poor role models, many emotionally out of control themselves, we can't expect kids to be any different, especially when no rules are enforced on authority.
As they say about a bad dog, they just had a bad owner. Parents are usually,
not always (especially with so many outside influences and meddling) to blame for the end product. It's never an easy job, especially in todays society.