Part 21 of Red Herrings covers still more responses to arguments that distract from the argument rather than address it directly. This week, the naturalistic fallacy.
The naturalistic fallacy was first described and named by British philosopher G. E. Moore in his 1903 book Principia Ethica. It describes the problem of trying to prove an ethical claim by appealing to a definition of “good” in terms of natural properties such as “pleasant,” “more evolved,” or “desirable.” For example, if something is both pleasant and good, inferring that “pleasant” and “good” are therefore the same quality is one bridge too far.
Moore stands in contrast to philosophers who argue that “good” can be defined in terms of natural properties we already understand. Instead, Moore argues that properties are either simple or complex, and complex properties are made from simple ones. Complex properties can be defined by breaking out their simple components, but the simple ones are indefinable. You can define “yellow” as the color of a ripe lemon, or as the primary color between green and orange on the visible spectrum, or as electromagnetic radiation with a wavelength between 570 and 590 nanometers, but none of those are sufficient to help a blind person perceive what you’re talking about. As Justice Potter famously observed about pornography, “I know it when I see it.” But that doesn’t enable one to produce a meaningful operational definition.