Since Hume it has been conventional to assert that you cannot get an “ought” from an “is”. Hume’s assertion of the “naturalistic fallacy”, combined with the collapse of the supernatural as a normative force, left Western morality in ruins. For if the world is all there is (e.g. there is no God), and morality cannot come from the world (what “is”), then morality cannot come from anywhere at all: It’s a figment of the imagination, or perhaps a social convention. Nietzsche surveyed the landscape and saw that God was dead and with His death, good and evil had died as well. Nietzsche’s prognosis proved correct as the 20th century unveiled a parade of failed moral theories.
But Nietzsche’s argument depends upon Hume’s. Is Hume’s argument sound? Is Hume in fact correct about the naturalistic fallacy? A number of 20th century philosophers, including Alisdair Macintyre, Philippa Foot, and Ayn Rand, argued that Hume was wrong. We can derive an “ought” from an “is”.
Specifically, we can derive an ought from an is as a conditional statement based on function: If X is the function of Y, then Y ought to do X. If Y does X, it is a “good” Y, and if Y does not do X, it is a “bad” Y. Let us call this the argument from function.
Consider two examples:
- A litigator has the function of “effectively representing his client in court”. If a litigator effectively represents his client in court, he is a good litigator. If a litigator does not effectively represent his client in court, he is a bad litigator.
- A heart has the function of “maintaining proper circulation in the body”. If a heart maintains proper circulation in the body, it is a good heart. If a heart doesn’t maintain proper circulation in the body, it’s a bad heart.
In arguing that we can derive an “ought” from an “is” in this manner, I do not believe I am presenting a particularly new or radical argument. Both Macintyre and Foot make the argument from function (and, in fact, I learned it from reading them); but the argument also has merit in that it reflects the common sense way in which we talk about what is and what ought be.
For instance, imagine a litigator who is wonderfully kind at his son’s birthday party, resulting in wonderful long-lasting memories for his son, but is absolutely dreadful in court, and loses his cases for his clients. Would a client not be justified in asserting of this litigator “Sir, you may be a good father, but you are a bad litigator.” Of course, we make such judgments every day.
Indeed, if a critic rejects the argument from function, he has paralyzed his ability his ability to take action in the world. If he has to hammer a nail into a wall, how does he decide which tool to use, if not by assessing the tool’s goodness or badness for the given purpose, which is to say, the right tool for the right job, which is to say, a tool with the appropriate function?
To avoid the side effects of rejecting the argument from function, even those who support Hume’s argument tend to accept that it’s legitimate to derive a functional “ought” from an “is”. But they argue that the functional “ought” is not the normative “ought”.
That is, to those who support the existence of the naturalistic fallacy (almost everybody except the Aristotelians), the statement “a litigator ought to effectively represent his client” and the statement “a man ought to do unto others as he would have them do unto him”, are two entirely different types of statements, and the validity of the former does not mean anything with regard to the validity of the latter.
We’ll turn to that point in the next essay.