Following the theory of Sigmund Freud, modern psychological texts state that moral behavior stems from a socially constructed moral conscience. This conscience is created through parental influences and social cues that are internalized throughout maturation. Because what is socially accepted differs across cultures, there can be no real definition of morality from the psychological understanding because morals become relative to customs, time, and place. C.S. Lewis directly responds to this issue with modern psychological theory. Although criticizing them later, Lewis was knowledgeable, interested, and learned in these psychological texts. In Mere Christianity, Lewis states that a human’s ability for moral reasoning is innate within the mind; there is a common moral law that guides the decision between right and wrong. Because the knowledge of what is moral is inherent, each person has an equal conception. In addition to this internal moral conscience, Lewis’s delineation of his theological view of morality also addresses the importance of social influences on moral behavior. But, instead of society creating a moral conscience, the conscience takes into account the impact that each choice has on society. Even though Lewis criticizes the modern psychological definition, he is able to merge the ideas into his concept, creating a more complete and nuanced understanding of morality that can be accepted across cultures.
Sechrist, Jennifer, "Morality and the Mind: A Discussion on Christian and Scientific Views Related to the Human Propensity to Sin" (2013). Symposium on Undergraduate Research and Creative Expression (SOURCE). 219.