Francis is a man of authority: doctrinal, but also political and economic. He has enormous symbolic capital; his words matter (which is why even his offhand remarks are reported internationally). In this case, a world leader is celebrating corporal punishment, and it is worth reflecting on the issue.

To begin, Francis's emphasis is not clear from the reports. He might have been celebrating not only smacking in particular, but also justice in general. For example, it is just to punish kids, but not disproportionally. So one strike is fine, but not beatings for days; the bottom is allowable, but not the face. This is applied easily elsewhere: you take a child's toy for transgression, but not their bed. Proportionality is a common ethical and legal principle, with precedents in philosophy and theology.

But Francis did not choose his example arbitrarily. While he might be motivated by a general notion of justice, he nonetheless praised a specific practice: spanking. And in the absence of any caveat, we can assume he endorses this in parenting. As do, according to studies, the majority of Australians and Americans (though the numbers are declining).

It is tempting to make this a simple matter of utility. Does spanking make better children? In general, no – although there are conflicting reports. Certainly ongoing and 'extreme' violence leads to long-term psychological and physical damage. The effects can be pathological: children who feel humiliated, betrayed, unsafe and unable to form enduring, mutually respectful relationships. There are serious health consequences. And some abused children treat their own children similarly: with unrestrained violence. Each act of aggression further entrenches vicious habits.

Nonetheless, some experts have argued that mild corporal punishment, judiciously used, can correlate with better behaviour. Whether it is superior to all other alternatives is another matter entirely, and the literature suggests that other forms of discipline are equally effective. Still, with these predictions it pays to avoid neat, universal assertions. Perhaps some children, in some circumstances, on some occasions, might benefit from corporal punishment. It is an empirical matter.

But this does not conclude the debate. Even if spanking were a foolproof method of producing virtuous progeny - and it most certainly is not - this would not mean parents ought to do it. The corporal punishment argument too easily slips into neat instrumentalism: if it works, do it. Yet the efficacy of something does not make it right. A deed can be useful without being good.

This is partly because the measure of something working well depends on what it's working for. In other words, ethics involves debate, not only about the means, but also about the ends. The goal of corporal punishment is often cowed obedience, and this is a trait I do not value highly. It has little worth in our family or, in my limited experience, in the workplace or public sphere. Respect for authoritative conduct is another thing altogether, and requires more than demonstrations of brute force.

But instrumental justifications of spanking are also lacking because they ignore questions of character. To be frank: I don't want to be the kind of man who hurts a smaller, weaker person. I don't expect to be our children's friend: I am their custodian. I do have to advise, second-guess and discipline them, often unpleasantly. But deliberately striking them, whether coolly or in a rage, takes advantage of their weakness. Even if done for their own good - and, again, this is problematic - it asks for a brutality I choose not to embody. Controlled violence in self-defence against a threatening peer? Sure. Violence against a 25-kilogram grade one? No. I'll find my "dignity" elsewhere.

Damon Young is a Melbourne philosopher. damonyoung.com.au