My simple analysis: Running a country is like running a home. At home, the parents hang the cane on the wall of living room. The kids see it everyday. The parents don't use it everyday. It's just hanging on the wall. Though the parents don't use it everyday, but the kids will think twice of doing something naughty because the cane is there. That's the way to keep law and order of the home as well as in the country. The law of caning and death penalty must be there. But the judges don't have to implement them on every case. But the potential criminals know the laws are there and the judges will use it on them. And they will think twice about doing something wrong. So what's the excuse that the criminals have when they are hauled to the courts? Who says capital punishment is against human rights? The justice system already state the penalties for respective crimes. Everyone, from students to the old, knows the law and punishment. So if criminals do the crime, they get the stated punishment. Nothing against the human rights. Not as if the judge gave a surprise punishment that is not in the books.
So if it is stated in the law that a thief will have his hands cut off, and everyone knows the punishment, the criminals get the punishment, it is not against human rights and is acceptable to you? I'm trying to follow your logic.
Whether the punishment is a "surprise" does not have to do with civility of punishment. I think it is quite a given that the punishment shouldn't and wouldn't be a surprise. Otherwise, we would be debating on the fundamental need for law and constitution, if indeed the punishment dished out is a "surprise". I don't think it even requires a discussion whether it being a surprise or not leads to whether it is a civilised law.
You see, the fundamental premise of your argument lies with the parenting tactics which aims to deter than to educate. If indeed, the consequence of doing something wrong at home, is to be caned, i have difficulty seeing how it is a logical consequence. Then if the child does not see the consequence of his actions beyond being caned into obedience, simply you are just complying and not making a moral decision that what is done is wrong. The child would not see why his action may have an adverse consequence for others or that it is morally wrong. I wonder how many parents would actually use reasoning to explain to the child his or her wrongdoings.
The aim of corrective philosophy towards punishment in law, aims to help criminals, some of which may not have the skills to secure a job, even if given a second chance. Imagine being jailed for 10 years. 10 years ago how was singapore like, what has changed, how many new jobs were created? And if they knew they would be caned and still do it, what then is the problem?