This text investigates the fundamental question of whether moral claims can be considered objective truths or if they are merely expressions of subjective preference. Gilbert Harman, a prominent philosopher, utilizes his background in epistemology and philosophy of mind to construct a framework that challenges the traditional view of moral realism. By examining the relationship between moral observation and scientific evidence, he argues that moral principles do not function in the same way as empirical facts, ultimately questioning the status of moral knowledge.

Experts frequently cite this work as a significant contribution to meta-ethics and the debate surrounding moral realism. Readers often note the academic density of the prose, which requires a strong background in philosophical terminology to fully grasp the author's arguments.