Naturalists believe that science is the most appropriate way to learn about the world and tend to be materialists, and they are the dominant philosophical community. Naturalism has its origins in empiricism and science: We wanted a way to learn about the world without prejudice and fantasy. Philosophy and religion tends to suffer from our psychological tendency to see the world in human psychological terms. There has to be a “reason” for everything to happen in the sense that there has to be a motive. The scientific process offered a way to avoid anthropomorphizing the world by reducing everything to thoughtless bits of matter. (We might start to worry when scientists offer us a non-anthropomorphic understanding of human beings and try to reduce us to thoughtless bits of matter.)
A commitment to naturalism caused most philosophers to reject moral realism because moral facts seem incompatible with a scientific perspective. Scientific questions concerning moral facts appeared insurmountable: How do we know about moral facts? How could we observe moral facts? How can you get prescriptive facts from descriptive facts? Can you derive ought from is?
Naturalists tend have the following ways to explain metaethics:
- Moral facts don’t exist because they aren’t compatible with science.
- Ethics can become a branch of science. Moral facts can be discovered using the scientific process.
Antirealists tend to think moral facts are incompatible with science because they would require a supernatural moral reality similar to Platonic forms.
Some antirealists don’t think ethics is meant to have moral facts because moral language is merely an emotional expression. Others agree that we intend to discuss moral truth, but there are no moral truths.
Essays on Moral Realism edited by Geoffrey Sayre-McCord didn’t adequately discuss the fact that some antirealist philosophers do agree that there are moral truths, but they think moral truths can also be understood in nonmoral language. Moral facts are merely reducible to nonmoral facts. Moral facts might reduce to facts about pleasure or facts about a culture.
Antirealist philosophers tend to be reductionists. The most real thing is physics. Chemistry could be reduced to physics and could be dispensed with. The only reason that we study chemistry or psychology is because these parts of science are messy and we are currently unable to reduce them to physics. We have a pragmatic justification for studying these parts of reality because it is useful to do so given our current limitations.
Realists think that moral facts are an irreducible part of reality that has not yet become part of science, but it could become part of science. Realists are non-reductionists. They often argue that we currently are unable to reduce each branch of science to physics, and each branch of science might contain irreducible elements. Although physics might cause all parts of reality, it does not necessarily constitute each part of reality. For example, physics might cause us to have minds, but a mind can have elements that are not reducible, such as qualia.
Even if naturalism is false, the quest to transform ethics into a branch of science is a solid strategy. We know that science is reliable, so transforming ethics into a science would assure us that ethics can be reliable. This is not unlike the hope by early philosophers that we could transform philosophy into something like mathematics. Simply put, the more ethics is like science, the more reliable it probably is.
I started with the common assumption that ethics couldn’t become a branch of science. The difficulties did appear to be insurmountable. However, the arguments within Essays on Moral Realism were quite promising. Not all naturalists are reductionists, and the epistemology of science is much more completed than one might think. The empiricism of science requires that we learn about the world through observation, but observation is theory-dependent. Observation using moral theory gives us moral facts.
Although there are relatively few non-naturalist philosophers, they could argue that moral facts are incompatible with science, but that is just a shortcoming of science because there are other methods of discovering facts other than science. This was not discussed in detail within Essays on Moral Realism.