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.
According to this line of thought, the first statement is a practical or pragmatic statement, while the second statement is a moral or normative statement. These ethicists would argue that the moral is not the practical; it’s something more. Kant has been, in modern times, the foremost proponent of this line of thought.
Against this charge, the defenders of the argument from function can offer several different responses.
Aristotle’s response was built on his metaphysical system of the four causes. The Final Cause was what we have called a thing’s function, and a thing’s goodness or badness was thus linked to whether it accomplished its Final Cause. Thus, the moral (properly understood in relation to a thing’s Final Cause) is the practical (properly understood in relation to a thing’s Final Cause). In terms of the argument from function, it can be expressed as: “The function of a thing is to fulfill its Final Cause; a thing ought to fulfill its Final Case; a thing which fulfills its Final Cause is a good thing.” In his Nicomachean Ethics, Aristotle demonstrates that man’s Final Cause is flourishing. He then enters into the specifics of how human beings can flourish, which hinges up their nature as rational and political animals.
This stance is, along with the entire edifice of Aristotelian metaphysics, still vigorous defended by Thomists presently and with considerable nuance that is absent in my simplification above. Because they have been ably defended elsewhere, I will not repeat their arguments here.
Ayn Rand, a Neo-Aristotelian (though not widely recognized as such by the popular press) also rejected the Kantian stance, directly asserting “the moral is the practical.” By questioning the Kantian presupposition that morality is something more than pragmatism, she places the burden of proof on the Kantian to explain why a person ought to do something that is not pragmatic; and of course, explaining an “ought” from an “is” is exactly the problem that the Kantian cannot solve because of the naturalistic fallacy.
But Rand also levels a positive argument for why the moral is the practical (or functional). She first defines morality as a code of values to guide a person’s choices. She then asks “why does a person need morality?” and concludes that the reason is because of the contingent nature of life. Some choices a person makes lead to continued life, and others lead to death. “The standard of value of the Objectivist ethics—the standard by which one judges what is good or evil—is man’s life, or: that which is required for man’s survival qua man. Since reason is man’s basic means of survival, that which is proper to the life of a rational being is the good; that which negates, opposes or destroys it is the evil.” In terms of the argument from function, Rand’s position can be expressed as: “The function of a person is to survive; a person ought to attempt to survive; a person who is surviving is a good person.” Rand, of course, designates reason as the means by which human beings survive, and this is essential to Objectivism, but not to our general meta-ethical discussion.
Objectivist scholars since Rand have tended to argue that survival and flourishing are in fact synonymous. As such, Objectivism is actually very close to Aristotelianism: Rand argues that morality is the code by which human beings survive and flourish through reason, and Aristotle argues that morality is the code by which human beings achieve their Final Cause of flourishing through reason and sociability.
Tara Smith’s Viable Valuables is the best work I have read on this topic of Rand’s ethics; highly recommended.
Alisdair Macintyre and Philippa Foot are up next in part 3.