Very Good Sentences

From Yokai Benkler's Wealth of Networks (free to download here):
the causal relationship between law and human behavior is complex. Simple deterministic models of the form “if law X, then behavior Y” have been used as assumptions, but these are widely understood as, and criticized for being, oversimplifications for methodological purposes. Laws do affect human behavior by changing the payoffs to regulated actions directly. However, they also shape social norms with regard to behaviors, psychological attitudes toward various behaviors, the cultural understanding of actions, and the politics of claims about behaviors and practices. These effects are not all linearly additive. Some push back and nullify the law, some amplify its the causal relationship between law and human behavior is complex. Simpledeterministic models of the form “if law X, then behavior Y” have been usedas assumptions, but these are widely understood as, and criticized for being,oversimplifications for methodological purposes. Laws do affect human behavior by changing the payoffs to regulated actions directly. However, theyalso shape social norms with regard to behaviors, psychological attitudestoward various behaviors, the cultural understanding of actions, and the politics of claims about behaviors and practices. 
And a great, simple example:
Decreasing the length of a “Walk” signal to assure that pedestrians are not
hit by cars may trigger wider adoption of jaywalking as a norm, affecting
ultimate behavior in exactly the opposite direction of what was intended.
This change may, in turn, affect enforcement regarding jaywalking, or the
length of the signals set for cars, because the risks involved in different signal
lengths change as actual expected behavior changes, which again may feed
back on driving and walking practices.
This Stag Staffer is constantly amazed at how often this simple, common sense point is lost in so much of our discourse.