I have admitted that morality can be justified only conditionally.
The primary condition is that people use only those beliefs that all
moral agents have. Morality must be known to all moral agents to
ensure that it cannot require beliefs that some of them do not have.
Thus, this condition is not arbitrary. When I talk about the beliefs
that all moral agentsshare, I mean those beliefs that any person
must have in order to be a moral agent. There may be other beliefs
that all rational persons share, but they are irrelevant to the justification
of morality. Before I discuss the content of the beliefs that
all moral agents share, I shall discuss some other features that a
person must have in order to be a moral agent, that is, to be subject tomoral judgment.
To be a moral agent, a person must have at least a certain
minimal intelligence, including some ability to reason. This minimal
intelligence involves being able to make at least the kinds of
simple inferences that we expect children age ten and older to
make. For example, they must be able to infer that this person
wants to avoid pain from the fact that all rational persons wantto avoid pain and that this person is rational. It also involves the
ability to use past experience as a guide. A moral agent must be
able to know at least the immediate and short-term consequences
of most of her actions. Moral agents need not be sophisticated in
their use of deductive and inductive reasoning, but unless they
have conflicting evidence, they must not only accept simpledeductive
and inductive inferences but make them spontaneously when
such inferences are relevant to their decisions. Also, unless they
Part II. The Moral Theory 87
have conflicting evidence, they must believe that the world is as
they perceive it to be.
A moral agent must also not have any relevant volitional disabilities.
7 She must be able to believe whatever the overwhelming
evidencesupports. She must also be able to act on her beliefs. She
must be able to act rationally, which requires almost always acting
rationally, for there can be no adequate reasons for acting irrationally.
Insofar as a person lacks the relevant minimal intelligence
or has relevant volitional disabilities, she is not a moral agent and is
excused from moral judgment. Actions that are unjustified violationsof moral rules do not count as immoral actions if the person
is completely excused. To claim to have a complete excuse is to
claim to be exempt from moral judgment. To claim to have less
than a complete excuse is to claim to be liable to less punishment
than someone with no excuse at all.
Knowledge or Beliefs Required
of All Moral Agents
Among the facts that all moral agents mustbelieve or know are
some facts about human beings. These facts include the following:
people not only are mortal but can be killed by other people;
people not only suffer pain but can be caused to suffer pain by
other people; people not only can become disabled but can be
disabled by other people; people not only can lose their freedom
but can be deprived of freedom by other people; and peoplenot
only can suffer a loss of pleasure but can be deprived of pleasure by
others. These facts can be summarized by saying that people are
not only vulnerable but can be harmed by other people. All moral
agents also know that no one knows everything, and not only do all
people make mistakes but other people can deceive them. People
88 Part II. The Moral Theory
have limited knowledge and arefallible. Each moral agent also
knows that she herself, like all other persons, is vulnerable, has limited
knowledge, is fallible, and can be harmed and deceived by other
In addition to these facts about human beings, moral agents
know something about the desires of rational persons. They know
that unless a rational person has an adequate reason for wanting
to die or to suffer pain,...