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J Med Ethics. 1985 Dec;11(4):198-204.

The brain-life theory: towards a consistent biological definition of humanness.


This paper suggests that medically the term a 'human being' should be defined by the presence of an active human brain. The brain is the only unique and irreplaceable organ in the human body, as the orchestrator of all organ systems and the seat of personality. Thus, the presence or absence of brain life truly defines the presence or absence of human life in the medical sense. When viewed in this way, human life may be seen as a continuous spectrum between the onset of brain life in utero (eight weeks gestation), until the occurrence of brain death. At any point human tissue or organ systems may be present, but without the presence of a functional human brain, these do not constitute a 'human being', at least in a medical sense. The implications of this theory for various ethical concerns such as in vitro fertilisation and abortion are discussed. This theory is the most consistent possible for the definition of a human being with no contradictions inherent. However, having a good theory of definition of a 'human being' does not necessarily solve the ethical problems discussed herein.


The unsettled question of when human life begins is a key issue in the abortion debate, and often figures in discussions of birth control, treatment of rape victims, fetal research, in vitro fertilization, and disposal of fetal remains. Goldenring proposes a brain-life theory, which maintains that a fetus becomes a biological human being when its brain begins to function at about eight weeks, and argues that this definition of humanness can be determined medically and scientifically, and has relevance for ethical, legal, and public policy decision making. He examines the problems created by other theories of humanness, such as "at conception" and "at viability," and discusses the implications of the brain-life theory for abortion and other bioethical issues such as fetal research.


The author advocates a brain-life theory of humanness, which asserts that the fetus is biologically a human being at the point at which its brain begins to function. Human life is thus viewed as a continous spectrum between the onset of brain life in utero at 8 weeks' gestation and the occurrence of brain death. This working definition is the converse of the medical definition of what constitutes death. It has important implications for areas other than abortion, including birth control, treatment of rape victims, fetal research, in vitro fertilization, and the disposal of fetal remains. As the seat of consciousness, emotion, and an individual's unique personality, the brain is the central human organ. Before the brain begins to function at about 8 weeks' gestation, there is just a set of tissues or a series of organ systems. The brain-life theory represents an intermediate stance between the at-conception theory of humanness and the viability theory. It has the advantage of being based on relatively objective rather than heavily evaluative criteria. This approach suggests that an abortion before 8 weeks' gestation kills potential human life, whereas abortion at a later point terminates actual human life. It further offers a clear choice point for contending with the ethics of fetal research: prior to brain function, expermentation on cultured, aborted, or about to be aborted embryonic tissue need not be subject to any special rules unless potential is valued as much as actuality. It must be recognized that social answers to ethical questions lie not in facts but in the value assigned to these facts. Although no biologic theory of humanness can define such values, it can clarify decisions and facilitate societal compromise.

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