In Peter Singer’s article “The Challenge of Brain Death for the Sanctity of Life Ethic”, he articulates that ethics has always played an important role in defining death. He claims that the demand for redefining death spreads rather from new ethical challenges than from a new, scientifically improved understanding of the nature of death. As thorough as his plea for dismissal of the brain-death definition is, he does not avoid the depiction of the complementary relationship between science and ethics. Quite the opposite, he tends to formulate a stronger, philosophically more consistent argument to help science and medical practitioners to define life, death, and the quality of life. In my commentary, I would like to focus on two issues presented in Singer’s study. Firstly, I will critically analyze the relationship between science and ethics. Secondly, I will follow on from Singer’s arguments differentiating between end of life as an organism and end of life as a person. The latter case is necessarily linked with man’s participation in her/his life, setting life goals, and fulfilling her/his idea of good life. Through the consequential definition of the dignity in ethics of social consequences, I will try to support Singer’s idea.