Thinking and Deciding

WHAT ARE MORAL JUDGMENTS? 391
From this analysis of the functions of morality, we can derive a couple of principles.
Imperatives and the naturalistic fallacy
The philosopher Richard M. Hare (1952, 1963, 1981) points out that a moral statement
is like an imperative statement. Logically, the statement “You should not steal”
resembles, in usage, the statement “Do not steal.” Moral statements tell us to do (or
not do) something. It would be inconsistent to say, “You should be kind to animals
— but don’t be.”
Moral conclusions do not follow, as an inference, from a set of premises unless at
least one of the premises is also of this imperative form (Hare, 1952). For example,
the argument, “It would be helpful to me if you opened the door; therefore, open the
door” is not valid without the added premise “Do whatever would be helpful to me.” 1
This has an interesting consequence. We cannot draw moral conclusions (logically)
from facts alone. From the fact that Harry’s father says that Harry should not
marry a gentile, it does not follow that Harry should not marry a gentile, unless we
also assume that he ought to do what his father says. From the fact that the Bible
says to keep the sabbath, we cannot conclude that we ought to keep the sabbath,
unless we assume that we ought to do what the Bible says. From the purported fact
that males evolved to spread their seed widely whereas females evolved to seek the
protection of a single male, we cannot conclude that infidelity in marriage is more
excusable for males than for females, unless we assume that people should do what
they (purportedly) evolved to do. From the purported fact that people were not made
to reproduce by artificial means, we cannot conclude that artificial insemination is
immoral, unless we assume that people ought to do only what is “natural.”
All of these mistaken inferences are examples of the naturalistic fallacy. To
commit the naturalistic fallacy is to draw a conclusion about what ought to be true
solely from what is true. It reflects a kind of confusion about the origin of moral rules
themselves.
In many cases, people who commit the naturalistic fallacy would be quite willing
to accept the premise they need — for example, that one should do what the Bible
says or that one should not do what is unnatural — but simply have not given the
matter much thought. Their acceptance of such principles is unreflective. A person
who says that artificial insemination is wrong because it is “unnatural,” for example,
may have no objection at all to our using telephones, automobiles, and railroads, and
may not notice that these things also violate the principle that whatever is unnatural
is wrong.
1 If we adopt Toulmin’s theory for extended logic, described in Chapter 4, we might say that this
inference is valid, but the warrant or backing must involve a statement such as, “Do whatever would be
helpful to me.”