It’s easy win a debate against a libertarian.  Just keep asking them questions.  Sure, they might have a few answers for how private police would work, or the courts, or the post office, but just keep asking them how everything would work, and they’re bound to trip.
This could be called “The Government of the Gaps” argument.  Whenever there is a hole in the free-market, people assume that the government should fill it.
This “Government of the Gaps” thinking puts libertarians on the defensive.  Some economists and libertarians have attempted to close the gaps by answering literally every question about how an international society for individual liberty would work.  Who would build the roads?  No problem.  Disease?  Done!  How about national defense?  Piece of cake.  The books “The Machinery of Freedom” by David Friedman and “Short Answers to the Tough Questions“, by Mary Ruwart do an excellent job of answering every question one could possibly ask, and if that’s not enough, there are more books with answers.
However, no matter how many answers there are, there will always be a new gap to find.
“Okay,” the big government guy will say, “So you’ve told me how private post-offices would work, but how many employees will they have?  What color will the post-offices be?  What if they’re paid too little?  Who will design the stamps?”
As long as libertarians are on the defensive, they are prone to tripping over one of these questions, and falling victim to the Government of the Gaps argument.  However, there is a solution.
The Government of the Gaps argument itself can be challenged.  For example, if libertarians ask, “Why does government have authority in the first place?” it puts those who believe in the authority of government on the defense.
Philosophers over the years have tried to answer this problem of political authority, but according to philosophy professor Michael Huemer, no one has a good theory yet.  In his book, “The Problem of Political Authority“, Michael Huemer goes through every philosophical justification for government’s authority, and shows enormous holes all the arguments.
These are not minor gaps either.  These are major, glaring holes in the justification for the state’s authority — big enough to drive a bus through.  He knocks down social contract theory with ease.  He bats away democracy so quickly it’s laughable.  He gives the consequentialists and the utilitarians a pummeling so hard, you almost feel sorry for them.  He even gives the non-aggression principle a run for it’s money.  And at the end of the match, no one is left standing.
According to Huemer, the burden of proof should be on those who believe in the authority of government, not on those who don’t.
To quote Penn Jillette, “My whole take on libertarianism is simply that I don’t know what’s best for other people.”
Well said, Penn.