You can find part 1 of this series here.
John E. Hare argues that trying to combine naturalism with objective morality doesn't really work. Using a Kantian ethical approach, he talks about a concept called the "Moral Gap," which has three parts. The first part is moral demand, which is our natural sense of duty that sets the standard for judging our actions. The second part is our natural capacities, which means our tendency to do wrong even though we want to do good. The third part is a "possible holy being," who is the source of moral demand, has higher moral abilities than we do, and can empower us do good. Hare explains:
This structure of the moral gap presents a certain problem, one which Kant saw in terms of “ought” and “can.” If it is the case that we ought to do something, it must be the case that we can do it. If, therefore, morality is too hard for us, it is not something we ought to be practicing. But Kant is quite certain that we are under the moral demand. He therefore makes use of the Western theological tradition, which relates the three parts of the moral gap structure this way: it says that the third part of the structure (the possible holy being) intervenes to change the second part of the structure (our natural capacities) so that they become adequate to the first part of the structure (the moral demand).1
In other words, the moral gap is between what we should do and what we can do. We are in need of divine assistance if we are to bridge that gap.
Since naturalists can't rely on this divine help, they need a different approach. Hare offers three alternatives: lower the moral standards, overestimate our natural abilities, or replace God with something else. Later in this discussion, I suggest that naturalists, who try to base morality on science, have unsuccessfully attempted all three of these strategies.
Why have scientific attempts to bridge the moral gap been unsuccessful? Because of a related, equally insurmountable gap: the gap between ought and is.
In a passage from A Treatise on Human Nature, David Hume criticizes the attempt to deduce normative assertions from descriptive ones. He highlights the subtle but significant shift in moral discussions from what is and is not to what ought and ought not to be. This idea, called Hume’s Law, states, "You cannot derive ought from is." Gillian Russell supports Hume’s Law as one of several "barriers to entailment,"2 asserting that purely descriptive premises can never lead to normative conclusions.
Russell explains that you cannot deduce how the world must be from premises that only describe how it is. She points out other barriers with similar logical forms and forces, such as the inability to deduce universal conclusions from particular premises, or conclusions about the future from premises about the past or present. In each case, the premises and conclusions are categorically different, creating a barrier. The same logic applies to the gap between descriptive statements about what is and normative claims about what ought to be.
Given the apparent validity of Hare’s Gap and Hume’s Law, I will argue in my next post that this gap is especially insurmountable for those who adhere to scientism.
John E. Hare, “Naturalism and Morality,” in Naturalism: A Critical Analysis (New York: Routledge, 2014), 189.
Gillian Russell, “How to Prove Hume’s Law,” Journal of Philosophical Logic (2021): https://doi.org/10.1007/s10992-021-09643-3.