The is/ought fallacy occurs when one draws a conclusion about what ought to be from statements about what is. For example, it would be a fallacy to argue that since everyone lies, everyone ought to lie. Just because something is the case, it does not mean that it ought to be the case. It would be a mistake to argue that since people do seek their own good, they ought to. It would be a mistake to argue that since people do naturally seek pleasure that they ought to seek pleasure.
Statements about what is the case are called Descriptive Statements because their aim is to say what is the case, that is, to describe what is
Some Descriptive Statements
Everyone lies
All human motivation is self-interested
Everyone seeks pleasure
Red is a color
Red is not a color
The number of stars in the universe is odd
The number of stars in the universe is even
No one lies
Different cultures have different moral standards
Notice that some of the descriptive statements above are false. A statement is descriptive if its intent is to describe what is that case, but it may fail to describe the situation correctly. So, “The number of stars in the universe is odd” and “the number of stars in the universe is even” are both descriptive even though at any given moment only one is true.
Statements about what ought to be the case are called Prescriptive Statements because they don’t merely describe what is the case, but they prescribe what ought to be the case. Prescriptive Statements are often called Normative Statements since they prescribe a norm or standard.
Some Prescriptive/Normative Statements
People ought to lie
People ought to be motivated only by self-interest
People ought to be motivation only by pleasure
People ought not lie
It would be nice if we could distinguish between descriptive claims from prescriptive claims by looking for the words “is” and “ought” but it is not so easy. For example,
Murder is wrong
is prescriptive, even though it does have the word “is” and does not have the word “ought”. Here’s why:
To say that murder is wrong is to say that one ought not to murder. It’s implicit, to be sure, but make a note: When we say that X is right or X is wrong, we are making a prescriptive claim, a normative claim (prescriptive and normative are synonymous).
The First Moral Theory of the Semester: Ethical Relativism
Two Correct Definitions
Ethical Relativism (definition 1): The view that what makes an act right or wrong is one’s culture: one’s culture is the only moral standard there is.
Ethical Relativism (definition 2): The view that one ought only to follow the rules of one’s culture, that there is nothing more to morality than that.
A Fallacious Argument in Favor of Ethical Relativism
Different cultures have different moral standards
Therefore, one ought only to follow the rules of one’s culture, that there is nothing more to morality than that.
Why is this argument invalid, fallacious?
Even though the most common argument in favor of Ethical Relativism is a fallacy, we need a good argument against it if we are justified in concluding it is false (It is one thing to say that an argument in favor of X is no good and it is quite another thing to say that there is good reason to think that X is false. If someone proposes an argument in favor of God’s existence that turns out to be faulty, we cannot, for that reason alone conclude that God does not exist).
Two Arguments Against Ethical Relativism
If ER is true, then moral change in a culture is neither moral progress nor moral decline.
Changes in a culture can be moral progress or decline.
Therefore, ER is false
If ER is true, then moral reformers are always wrong to oppose the culture’s moral standard.
A moral reformer may sometimes be right to oppose the culture’s moral standard.
Therefore ER is false
Both arguments are valid. Both have all true premises.
Conclusions
So the logic section was grueling but if you can see that Modus Tollens is a valid argument form and you believe that a culture can advance or decline morally, you also see that Ethical Relativism must be false. In the same way, if you see that Modus Tollens is a valid argument form and you believe that a moral reformer can sometimes be right to oppose a culture’s standard, then ER must be false.
Sample Solution
