A legal positivist, a purposivist, and a realist all work for the highway patrol.
A motorist is driving down a road. The legal positivist pulls him over and begins writing out a ticket.
“Why on earth am I getting this ticket?” asks the driver.
“You were going 51 km/h in a 50 zone,” explained the positivist. “The law is very clear and was enacted validly. I have to give you a ticket.”
The driver rants and raves at the positivist.
“This is ridiculous, bloody revenue gatherers!” he says. But he ultimately takes the ticket and carries on driving down the road, a little slower than before.
The driver doesn’t get far before the purposivist pulls him over and begins writing a ticket.
“Why on earth am I getting this ticket?” asks the driver.
“You were going 40 km/h in a 50 zone,” explained the purposivist. “The law is designed to prevent unsafe speeds and you were going so slow that you were unsafe. I have to give you a ticket.”
The driver gets even angrier at the purposivist.
“I can’t believe you people. First I drive too fast, now I drive too slow!” But he ultimately takes the ticket and carries on driving down the road, this time being certain to stick to exactly 50km/h.
The driver doesn’t get far before he is pulled over by the legal realist, who begins writing him a ticket.
“Hey!” said the driver. “I wasn’t driving too fast, I wasn’t driving too slow. What on earth are you giving me this ticket for?”
“Well,” said the legal realist. “You were awfully rude to my colleagues.”
Strictly obiter 