I came across this short well-reasoned essay via reddit, but most of the discussion there was by people who (ironically enough) appeared not to have read it. The comment section under the article itself was similar. Some seemed not to have read the first paragraph.
Prison time is a very severe punishment. JS Mill likened it to being consigned to a living tomb.* Any society that employs it should do so with care and restraint. Yet we do not. Partly because we think that prison is a humane punishment, it is drastically over-used in many countries, to the point of cruelty. Aside from failing in humanity, prison does not even perform well at the specific functions of a criminal justice system, namely, deterrence, retribution, security, and rehabilitation. We need to reconsider our over-reliance on prison, and reconsider whether other types of punishment, including capital and corporal punishment, may sometimes be more effective and more humane.
The author's arguments against the imprisonment system, and for alternative methods of punishment, are interesting. They touch upon ideas which are hard to consider rationally. The very idea of punishment is something most people appear to find unpleasant. Indeed so it must be if something is to be considered a punishment.
Flogging is barbaric and ugly. Yet that in itself does not mean it is cruel or inhumane or otherwise unfit as a punishment. Punishments, by definition, are supposed to be very unpleasant.
I found some relevant previous discussion on Less Wrong (Crime and Punishment, The Wrath of Kahneman), and Overcoming Bias (Prison is Cruel), but these seem to be about specifics, and not the system in general.
I am curious both what the scientific consensus is on punishment systems, and what Less Wrong thinks of them. With such an emotionally charged issue, it's hard to find rational discussion about it.