This work examines the enduring question of whether a stable human nature can be identified and defined. Drawing on philosophical anthropology and comparative psychology, it considers how ideas about human beings have been shaped by scientific, historical, and conceptual frameworks. The inquiry moves between questions of psychology, culture, and the limits of universal claims about humanity, asking how much of what is called human nature is innate, constructed, or inferred from comparisons with other forms of life. Rather than treating the subject as a simple yes-or-no problem, the book presents human nature as a complex object of investigation. It is suitable for readers interested in the foundations of psychology, anthropological theory, and philosophical debates about what distinguishes human beings and whether those distinctions can be grounded in evidence.