Since ancient Greek times, the question of free will and, consequently, the culpability of offenders has been repeatedly addressed. In the 20th century, the idea of the existence of free will was vehemently criticized by various scientific disciplines: both Freud and his successors, as well as modern social sciences and natural scientific fields such as comparative behavioral research, behavioral genetics, and neuroscience, challenge the concept of free will. The unconscious, social conditioning, our genes, and nonlinear, uncontrollable neural processes are said to determine our behavior. Is the idea of free will merely another illusion of humanity? This discussion is also crucial for forensic psychiatry: Are actions a priori determined by our brain activity?.