Naturalistic Fallacy, The
KeywordsNatural Selection Factual Statement Ethical Conclusion Moral Statement Evolutionary Psychology
The naturalistic fallacy, as it is colloquially used, refers to the logical fallacy made when one derives moral prescriptions from naturally occurring phenomena or factual statements about the world.
Moore (1903) coined the term the naturalistic fallacy to refer to instances in which one conflates morality with any other construct (e.g., pleasure, fulfillment, social good, God’s will). Moore argued that, for instance, while morality and pleasure may both be used to describe a particular act, it does not follow that morality and pleasure are equivalent constructs. The modern usage of the naturalistic fallacy, however, most often refers to David Hume’s is/ought fallacy, wherein Hume (1739) argues that statements regarding how things ought to be (i.e., moral statements) cannot exclusively be derived from how things are (i.e., factual statements). In other words, moral prescriptions cannot be derived solely from factual statements about the world.
Moral Prescriptions from Evolutionary Principles to Morality
An example of the naturalistic fallacy might include statements asserting the morality or utility of Darwinian natural selection due to its existence in the natural world. Such erroneous reasoning led philosopher Herbert Spencer (1897) to advance a science-based morality in which he proposed that human welfare would be maximized by allowing the weak and poor to essentially die out while the “fittest” thrived in society (but see Wilson et al. 2003). Spencer’s (1897) philosophy was also based in a critical misunderstanding of natural selection, whereby he mistakenly assumed that evolution necessarily leads to human progress or advancement.
The naturalistic fallacy is commonly used to describe criticisms of evolutionary psychology that rest upon the notion that factual descriptions of naturally occurring behaviors are equivalent to moral prescriptions or justifications. For instance, critics accused Thornhill and Palmer (2000) of legitimizing rape as a moral behavior and blaming victims for its occurrence by studying rape as a naturally occurring phenomenon (e.g., Kimmel 2003; Rosser 2003; Shields and Steinke 2003). These allegations were made in error; it is not logically valid to claim that descriptions of rape as a natural behavior (i.e., occurring in nature) are equivalent to descriptions of rape as a moral behavior, and Thornhill and Palmer (2000) did not imply as much. Other critics, such as certain feminists, commit the naturalistic fallacy by wholly misperceiving the evolutionary investigation of human behavior as “a guide to moral behavior and policy agendas” (Nelkin 2000, p. 20), intended to legitimize and promote the subjugation of women (e.g., Kay 1990; Tang-Martinez 1997).
While the term “naturalistic fallacy” is frequently used in this way within the field of evolutionary psychology (i.e., conflating “is” with “ought”), Wilson et al. (2003) charge evolutionary theorists with misusing the term. Specifically, they assert that evolutionary psychologists inappropriately characterize the above criticisms of their field as examples of the naturalistic fallacy. For example, Wilson et al. (2003) contend that Spencer (1897) was, in fact, not exclusively deriving “ought” from “is,” in line with Hume’s (1739) definition of the naturalistic fallacy. Rather, they argue that Spencer (1897) did not invoke “naturalness” in his argument’s factual premise to derive his ethical conclusion; instead, Spencer (1897) defended social practices that favored the strong and the wealthy because he believed that over time, they would produce a better society. Furthermore, Wilson et al. (2003) argue that evolutionary psychologists frequently fail to consider the full moral implications of their findings by neglecting to classify moral behaviors as products of natural selection. However, critics of evolutionary psychology who claim the field seeks to uphold social norms such as sex/gender-based inequality nevertheless misinterpret the intentions of researchers who utilize an evolutionary framework to study human psychology and behavior (i.e., who acknowledge that negative behaviors evolved in response to selection pressures and investigate the underlying causes of such evolved behaviors, but do not necessarily condone their use). Moreover, advances are being made in developing the evolutionary psychology of morality, which investigates the moral behaviors of human beings (see Shackelford and Hansen 2016).
- Hume, D. (1739). A treatise on human nature. London: John Noon.Google Scholar
- Kay, H. H. (1990). Perspectives on sociobiology, feminism, and the law. In D. L. Rhode (Ed.), Theoretical perspectives on sexual differences (pp. 74–85). New Haven: Yale University Press.Google Scholar
- Kimmel, M. (2003). An unnatural history of rape. In C. B. Travis (Ed.), Evolution, gender, and rape (pp. 221–233). Cambridge, MA: MIT Press.Google Scholar
- Moore, G. E. (1903). Principia ethica. Cambridge: Cambridge University Press.Google Scholar
- Nelkin, D. (2000). Less selfish than sacred? Genes and the religious impulse in evolutionary psychology. In H. Rose & S. Rose (Eds.), Alas, poor Darwin: Argument against evolutionary psychology (pp. 17–32). New York: Harmony Books.Google Scholar
- Rosser, S. (2003). Coming full circle: Refuting biological determinism. In C. Travis (Ed.), Evolution, gender, and rape (pp. 413–424). Cambridge, MA: MIT Press.Google Scholar
- Shackelford, T. K., & Hansen, R. D. (Eds.). (2016). The evolution of morality. New York: Springer.Google Scholar
- Shields, S. A., & Steinke, P. (2003). Does self-report make sense as an investigative method in evolutionary psychology? In C. B. Travis (Ed.), Evolution, violence, and gender (pp. 87–104). Cambridge, UK: Cambridge University Press.Google Scholar
- Spencer, H. (1897). Principles of ethics. New York: Appleton.Google Scholar
- Thornhill, R., & Palmer, C. T. (2000). A natural history of rape: Biological bases of sexual coercion. Cambridge, Mass: MIT Press.Google Scholar