Thomas Hobbes envisioned human interactions before a central government to keep them in line as each man against every other man. That, I’m sure, is not a historical fact but is rather a philosophically plausible explanation for the need of government and a social contract.
Even the anarchist, however, must accept that, even without formal laws or a central government, serious interpersonal conflict, such as rapes and murders, would still be rather rare events. Why would this be? The answer is that people, being social animals without impressive physical attributes besides their large brains, naturally rely on each other.
A dichotomy is drawn between crimes that are mala se (inherently bad or wrong) and mala prohibita (bad or wrong because the law says so). Aberrents will and always have committed crimes; they do this in spite of the law, but they’re a relatively small minority. For example, the death penalty may be a deterrent, but then again, it won’t always be so.
More important for minimizing crimes is that we are, as I often say, social creatures. As social animals, we rely on each other. President Obama recently gave a speech in which he spoke of everyone in this country receiving help from someone along the line to be economically well off. That speech went to my heart because it sounded like a speech from someone who shares my political philosophy (Democratic Socialist).
People interact with each other so much that it’s almost amazing that we get along so much most of the time. Amazing, perhaps, but not surprising; our caring for each other is a part of our biological niche.