For lecture videos, readings, and other class materials, you can sign up for this independent study course at academy.mises.org.

1. Libertarian Ethics, Lecture 3
Rothbard’s Ethics

2. Rothbard and Mises
●Rothbard and Mises have very similar
views about policy. Both support the
free market and oppose socialism and
government intervention in the
economy.
●There are differences about property
rights,but I’ll discuss this topic later.
●The main difference between them
concerns the foundation of ethics.

3. Difference About Objectivity
●Rothbard, in contrast with Mises, thought that
ethics is objective. If we say, e.g., that we
ought to promote the free market, this tells us
what we ought morally to do. It’s isn’t only a
claim about how we can realize the
preferences for peace and prosperity that we
in fact have.
●Rothbard would not say that morality is just a
social institution or device. It is discovered
rather than invented.

4. Is Ethics Objective?
●One of the most important controversies in
ethics is whether morality is objective. As
most philosophers understand this, the
question means, “Can moral judgments be
true or false”?
●To answer “No”, is to accept subjectivism.
Suppose I like vanilla ice cream but you don’t.
Neither of us is correct or incorrect.
Subjectivists think that moral judgments are
like this.

5. Where Mises and Rothbard
Disagree
●It’s important to see exactly what the
issue is between Mises and Rothbard
about objectivity.
●Mises certainly thinks that many
judgments that have something to do
with ethics are true or false. E.g., “The
free market enables people to attain
their preferences” is true.

6. Disagreement Continued
●Ultimate value judgments, according to
Mises, are neither true nor false. E.g., if
someone doesn’t want to be in pain, and this
is not a means to some further end, Mises
would say it doesn’t make sense to claim that
this preference is correct or incorrect.
●Rothbard would disagree. He thinks that
value judgments are objective, in the
straightforward sense in which judgments
about facts are true or false.

7. Natural Law
●How can Rothbard show that ethics is
objective?
●He does so by appealing to natural law,
especially as developed by St. Thomas
Aquinas.
●This raises a problem: Aquinas was a
Catholic theologian, who argued that natural
law was part of Divine law. Does accepting
natural law commit you to accepting the
claims of a particular religion or, if not that, at

8. Natural Law and God
●Rothbard argues that even though Aquinas
thought natural law was part of God’s law, it
depended only on human reason. It wasn’t
dependent on accepting Biblical revelation.
●Rothbard is here in accord with Aquinas
himself.
●The great Dutch legal theorist Hugo Grotius
said, “What we have been saying would have
a degree of validity even if we should
concede [etiamsi daremus] that which cannot
be conceded without the utmost wickedness,

9. Divine Command Ethics and
Positivism
●Rothbard draws an interesting parallel
between divine command ethics and
positivism.
●According to divine command ethics, at least
in certain versions, ethics has no basis in
reason. Ethical rules are just commands of
God.
●Legal positivists hold that laws are just
commands of the legislator.

10. Essences
●How does natural law show that ethical
judgments are objective?
●Rothbard appeals to essences.
●An object’s properties can be divided into two
classes. One class is the essential
characteristics. The object wouldn’t be the
object that it is without these properties. E.g.,
it is water’s essence to be composed of
hydrogen and oxygen. Nothing without this
property is water.
●The rest of the properties of the object are are

11. The Human Essence
●Rothbard suggests we can determine
the essence of human beings, just as
we can for other things.
●But isn’t he open to objection here?
Wouldn’t an account of the human
essence be part of anthropology, not
ethics? How could an account of the
human essence tell us what we should

12. Essence and Flourishing
●Rothbard answers these questions by
appealing to the concept of flourishing or
happiness.
●If you are to flourish, you need certain things.
These requirements are dictated by human
nature.
●So far, this is parallel to Mises: it just says, “If
you want to flourish, you should do such-and-
such”. This is like Mises’s claim, “If you want
peace and prosperity, you should favor the

13. Flourishing Continued
●Rothbard does not take human flourishing as
a mere hypothetical. In the natural law view,
it’s objectively true that this is a good---you
should want to flourish.
●Rothbard rejects Hume’s Law. From the fact
that certain things are needed for human
beings to flourish, Rothbard thinks that it
follows that we ought to want these things.

14. Rejection of Hume’s Law
●How is it supposed to follow from the fact that
we need to do certain things to flourish that
we unconditionally ought to do these things?
Most people certainly want to flourish, but
what if someone didn’t?
●Suppose you respond, Well, if you want to
flourish, you should do what you need to
flourish”? This is Mises’s position, and also
Ayn Rand’s, but it isn’t standard natural law
theory.

15. Natural Law and Hypotheticals
●But in standard natural law theory, what you
ought to do isn’t dependent on your choosing
something. You simply ought to do it.
●If you have a choice, then morality consists of
hypothetical imperatives: if you choose to live,
you should. . .
●Standard natural law theory isn’t satisfied with
this.

16. Tendencies
●How do we get these non-hypothetical
oughts?
●Rothbard notes that living things have certain
tendencies. E.g., a normal colt will develop
into a horse. A colt that failed to do this would
be defective. A good horse is one that
develops normally.
●A animal “should” develop according to its
tendencies; this is just what “should” means.
Thus, we should want to flourish. A person
who didn’t do this would be abnormal.

17. An Objection
●There is a famous objection to arguments of
this sort. Suppose we ask, “Ought we to do
what we need to flourish”? If “ought” means
“what we need to do to flourish”, the question
would make no sense. It would be asking,
“ought we to do what we ought to do?”
●But the question does make sense, or at least
seems to. This is a variation of G.E. Moore’s
famous “open question” argument. Rothbard
could reply that if we think the question
makes sense, we are mistaken.

18. Natural Law and Political
Philosophy
●Rothbard says that political philosophy is
concerned with only part of ethics.
●It is confined to delimiting the permissible use
of force. Ethical issues that don’t involve force
are not covered. Political philosophy
establishes people’s rights, i.e., claims that
people can use force to secure.
●The separation between political philosophy
and other parts of ethics comes from Locke.
The 19th
century German philosopher Fichte
also stressed it.

19. Natural Law and Custom
●According to Rothbard, we use reason
to determine what we need to flourish.
●In contrast to Hayek and Hazlitt,
Rothbard is suspicious of the role of
custom and common law.
●The results of common law must be
tested by reason. They don’t have a
presumption of truth.

20. Self-Ownership
●What do we need in order to flourish?
Rothbard thinks that each person needs
to be a self-owner. Each person has the
right to decide what to do with his or her
own body.
●You don’t have to donate a kidney or
blood to someone even if he needs one
of these items more than you do. It’s

21. Self-Ownership Continued
●Self-ownership isn’t a philosophically
problematic concept, contrary to what some
people think. All it means is that each person
should be in control of decisions about his
own body, such as the kidney and blood
donations examples just mentioned.
●Self-ownership does not imply that the mind
is separate from the body and owns it. It
involves no assumptions about the mind-body
relation.

22. Alleged Problems With Self-
Ownership
●The “self” in “self-ownership” is
reflexive. Suppose we say that
someone lacks self-esteem. We don’t
mean that the person’s self lacks
esteem for something else, e.g., the
person’s body. We just mean that he
doesn’t regard himself very highly. In
like fashion, a self-owner controls

23. Problems Concluded
●Some people still object. They say, “This isn’t
real ownership. Ownership must involve a
separation between owner and what is
owned.”
●I find this an odd objection. “Ownership” isn’t
a thing in the world, but a term invented for
our convenience. It doesn’t have an essence:
we can define it as we please.
●If you don’t like the term self-ownership, feel
free to use some other term. Nothing turns on
what word we use.

24. The Case for Self-Ownership
●Rothbard makes the case for self-ownership
by contrasting it with alternative principles.
These include slavery and a system in which
each persons “owns” parts of everyone. The
latter system couldn’t work.
●Isn’t it obvious that slavery is wrong?
Rothbard is, at least at some points, a moral
intuitionist, someone who thinks that we can
grasp the truth about at least some moral
claims. “E.g., “it’s wrong to kill babies for fun”.
If someone asked why this was true, he

25. Property Rights
●Given self-ownership, Rothbard proceeds to
develop an account of how persons acquire
property.
●Land and other resources start out unowned.
People own their own labor and when they
mix their labor with the unowned land in an
appropriate way, they acquire the land.
●Property rights leave no room for a legitimate
State.

26. Mises on Property Rights
●As Danny mentioned in his lecture, Mises
thinks we need a legal system that gives
people stable property rights. The free market
couldn’t function without them.
●It doesn’t follow, though, that for Mises these
rights have to be acquired through
homesteading; any stable system that permits
the free market to operate will suffice.

27. Mises Continued
●Mises rejects the Lockean account on the
ground that existing property titles can’t be
traced back to acts of Lockean acquisition.
●Mises stresses that in the free market, the
real owners of productive property are the
mass of the consumers. Their spending
decisions determine gains and losses in
ownership. It’s open to a Misesian to support
a homesteading system as the best option;
but, unlike Rothbard, a Misesian won’t say
that people have a natural right to property.