Many libertarians appear to believe that libertarianism can be stated as a simple and convincing moral principle from
which everything else follows. Popular candidates are 'It is always wrong to initiate coercion' and 'Everyone has the
absolute right to control his own property, provided that he does not use it to violate the corresponding rights of
others.' If they are right, then the obvious way to defend libertarian proposals is by showing that they follow from the
initial principle. One might even argue that to defend libertarian proposals on the grounds that they have desirable
consequences, as I have done throughout this book, is not only a waste of time but a dangerous waste of time, since it
suggests that one must abandon the libertarian position if it turns out that some coercive alternative works better.
One problem with deducing libertarian conclusions from simple libertarian principles is that simple statements of
libertarian principles are not all that compelling. Lots of people are in favor of initiating coercion, or at least doing
things that libertarians regard as initiating coercion. Despite occasional claims to the contrary, libertarians have not yet
produced any proof that our moral position is correct.
A second problem is that simple statements of libertarian principle taken literally can be used to prove conclusions that
nobody, libertarian or otherwise, is willing to accept. If the principle is softened enough to avoid such conclusions, its
implications become far less clear. It is only by being careful to restrict the application of our principles to easy cases
that we can make them seem at the same time simple and true.
The easiest way to demonstrate this point is with a few examples. In order to define coercion, we need a concept of
property, as I pointed out at the beginning of this book—some way of saying what is mine and what is yours. The
usual libertarian solution includes property rights in land. I have the absolute right to do what I want on my land,
provided that I refrain from interfering with your similar right on your land.
But what counts as interfering? If I fire a thousand megawatt laser beam at your front door I am surely violating your
property rights, just as much as if I used a machine gun. But what if I reduce the intensity of the beam—say to the
brightness of a flashlight? If you have an absolute right to control your land, then the intensity of the laser beam
should not matter. Nobody has a right to use your property without your permission, so it is up to you to decide
whether you will or will not put up with any particular invasion.
So far many will find the argument convincing. The next step is to observe that whenever I turn on a light in my house,
or even strike a match, the result is to violate the property rights of my neighbors. Anyone who can see the light from
his own property, whether with the naked eye or a powerful telescope, demonstrates by doing so that at least some of
the photons I produced have trespassed onto his property. If everyone has an absolute right to the protection of his own
property then anyone within line of sight of me can enjoin me from doing anything at all which produces light. Under
those circumstances, my 'ownership' of my property is not worth very much.
A similar problem arises with pollution. Libertarians sometimes claim that since polluting the air over anyone else's
property is a violation of his property rights, pollution can be forbidden in a libertarian society except when the
pollutor has the consent of the owners of all affected land. This argument is used to attack schemes such as effluent
fees (discussed in Chapter 26), which are designed to limit pollution to its economically efficient level—the point at
which further reductions cost more than they are worth—but not to eliminate it.
Here again, the problem is that an absolute right to control one's property proves too much. Carbon dioxide is a
pollutant. It is also an end product of human metabolism. If I have no right to impose a single molecule of pollution on
anyone else's property, then I must get the permission of all my neighbors to breathe. Unless I promise not to exhale.
The obvious response is that only significant violations of my property rights count. But who decides what is
significant? If I have an absolute property right, then I am the one who decides what violations of my property matter.
If someone is allowed to violate my property with impunity as long as he does no significant damage, we are back to
judging legal rules by their consequences.
A similar problem arises if we consider effects that are small not in size but in probability. Suppose I decide to play
Russian roulette, with one small innovation; after putting one cartridge in my revolver and spinning the cylinder, I
point it at your head instead of at mine before pulling the trigger. Most people, libertarian or otherwise, would agree
that you have every right to knock the gun out of my hand before I pull the trigger. If doing something to someone (in
this case shooting him) is coercive, then so is an action that has some probability of doing that something to him.
But what if the revolver has not six chambers but a thousand or a million? The right not to be coerced, stated as an
absolute moral principle, should still apply. If libertarianism simply consists of working out the implications of that
right, then it seems to imply that I may never do anything which results in some probability of injuring another person
without his consent.
I take off from an airport in a private plane with a cruising radius of a thousand miles. There is some (small)
probability that my instruments will fail, or I will fall asleep, or for some other reason I will go wildly off course.
There is some probability that the plane, having gone off course, will crash. There are things I can do which will
reduce these probabilities, but not to zero. It follows that by taking off I impose some (small) probability of death and
destruction on everyone through whose roof I might crash. It seems to follow from libertarian principles that before
taking off I must get permission from everyone living within a thousand miles of my starting point.