Apprehension after the fact does actually prevent the perpetrator from committing a substantially similar crime, as least for as long as they're in custody. In addition, things that increase the likelihood of getting caught serve as a deterrent for other potential criminals.

Which of course is not to say that on balance mass surveillance of public spaces is a net benefit. But it does have some benefits, and it does the debate disservice to deny them.

> In addition, things that increase the likelihood of getting caught serve as a deterrent for other potential criminals.

Heard studies that proves the opposite. The kind of crimes that substantially deterred by the chance of getting caught are crimes which the perpetrator has had time to consider for a length of time. Violence of the moment is generally not deterred by the chance of getting caught, and is practically unaffected by surveillance of public spaces.

Or to mention a few practical examples, road rage isn't effected by surveillance. A person being enraged at a bar isn't effected by surveillance, through a fight outside the bar could. Premeditated murder is deterred by the punishment/likelihood of getting caught, but other forms of murder isn't. Based on the theory, I would also guess that sexual harassment is decreased while rape isn't.

I absolutely agree that not all crimes are deterred by the likelihood or consequences of being caught. But the intersection of crimes that are committed in public and crimes that are committed dispassionately, where the likelihood of being caught can deter them, is non-zero; therefore public surveillance can deter crimes, and one cannot simply dismiss that possibility when considering the pros and cons of mass public surveillance

Wrong, and a news story this week proves it. I can't find the link but there was a known sex offender who had served his sentence. A woman was walking home alone late at night so someone monitoring public CCTV decided to follow her via the cameras. They then saw the sex offender approach and begin verbally harassing her. Police were called and got there before things got more serious.

"Someone monitoring public CCTV" is where it tends to break down.

That seems awfully nitpicky. Cameras cannot physically stop a crime in progress, but neither can any other remotely reasonable public safety measure.

The best prevention is preventing criminal behaviour. By taking care of mental health, community, opportunity and support.

Edit/Comment: best in this case does not mean cost-effective or easy ;)

The vast majority of violent criminals are not mentally ill.

I meant mental health, I didn't mean mentally ill. Mental health even includes being unhappy.

Not sure if violent acts are entirely random, I have not enough expertise on that. Currently I assume most acts of violence are not entirely random; and if they are, they are a mental/medical/neurological illness. And it might be perfectly normal to be dispositioned to be like this, but it would still be a problem.

It does not seem like a stretch to expand the definition of mental illness to include mental conditions which predispose to the commission of violent crimes. Certainly such conditions are maladaptive for the sufferer.

Most violence is morally motivated[1], so working on changing societal norms are most important. 1: http://www.doktorikool.ut.ee/kstt/orb.aw/class=file/action=p...

I don't see how reclassifying crime as illness is going to help anything except making psychiatry much less credible.

"neither can any other remotely reasonable public safety measure"

How about allowing citizens to carry their own protection?