Americans have heard a great deal of talk about "quality of life" in recent weeks with the prominence of the Terri Schiavo case in the national media. For fifteen years Terri Schiavo existed in what some physicians have labeled a persistent vegetative state--others say she may have been in a state of minimal consciousness. Her husband (now living in a common law relationship with another woman) won the right to have her feeding and hydration removed, arguing that years ago she verbally conveyed her wishes not to be kept alive in such a state. Terri's parents fought to keep her alive. The courts and public opinion weighed heavily against the parents and in the end Terri was deprived of hydration and nutrition. Many commentators on the tragic battle over her life suggested that she was "brain dead" and a lost cause, that her intellectual abilities would never be what they once were, and that this was a partial argument for why she should be "allowed to die." According to such accounts Terri, as an individual, had ceased to be fifteen years prior to the final legal conflict. You might even say that about a decade and a half ago Terri Schiavo "lost her soul." Since Terri as a person was really gone, her body should be allowed to die.
You won't hear much "soul talk" in theology and ethics these days. The linguistic spotlight on humans has been refocused squarely in the physical realm, and in this refocusing many physicalists, functionalists, and monists insist that they are keeping closer to what the foundational Hebrew and Christian texts really teach, in comparison to those who cling to talk of souls as ghostly things that manipulate the fleshy machine of the body. While these approaches may sound more affirming of the embodiment of human existence, they leave us in places of far greater ethical difficulty than do most forms of Aristotelian or Thomistic dualism. In some physicalist corners the concept of soul is morphed into a concept of "soulish properties"--the ability to have personal relationships, to pray, to voluntarily make moral decisions--a list that could be inexhaustible. In this line of thought "soul" is a set of functions that emerges from neurological functioning, rather than a human nature or essence that provides the foundation for the emergence of distinctly human neurological functioning: First you have the neurons, the neurons start working, and "the soul" emerges. This equating of the "soul" with a set of functions or processes--what cognitive psychologists might refer to as "mind"--is the same faux paux Descartes made, but one that Aristotle and Aquinas did not: In Aristotle the mind is a subset of abilities defined by the essential nature of the creature (the soul). The soul precedes all else. We are humans first by nature, not by function.
Things get confusing when "soul" is rejected in a traditional sense by physicalists but accepted as a set of properties. We may first be told that "we are souls; we don't have souls" only to be told later that the soul is nothing more than "soulish properties." This seems to lead back to being able to say "we have souls" by virtue of having these properties, negating the previous assertion that "we are souls" and "don't have souls." So if the "soul" is to be defined as a set of functions, what about human beings that lack these functions or processes--perhaps due to brain damage or developmental disability--do they lack "souls" or "personhood" if they lack whatever abilities the physicalists have linked with these terms? In the Schiavo case many in the media seemed to be making this claim: "Her quality of life will never be the same and we should be let her go" or "She's not there anymore." Her husband made the claim that his wife "died fifteen years ago." From a Thomistic standpoint such statements are illogical; if you are a living human being you have a human soul. If you lacked a soul, that which provides the nature of your very existence, you'd be a human corpse. Terri Schiavo was not in the process of dying, at least no more than any other human being, nor was she brain dead as many in the media alleged. Despite profound cortical damage, all of Terri's basic physiological systems were functioning normally under the control of surviving brain structures. Biological death was far from imminent. From a physicalist position, however, it would seem that you could still be a living human being but lack your "soul." This seems to be the popular analysis of what to make of people suffering from severe neurological impairments, people such as Mrs. Schiavo or perhaps President Reagan in the last stages of Alzheimer's disease: They lose their souls.
The Anglican theologian Lindsay Dewar commented that "To prevent something good from developing is morally hardly distinguishable from destroying the end product when it has come into being." This conclusion is based upon an element of Aristotelian thought usually worked out in scholastic moral theory, that the worth of a thing is dependent not upon the actualization of potential, but upon the potential itself that rests within the nature or essence of a thing. Knowledge of and concern for the human nervous system is in no way foreign to this line of thought--indeed the theistic or humanistic physician would of course wish to know how best to foster and maintain the health of the brain during all stages of development and how to avoid or prevent damage to this very delicate arrangement of cells and chemicals. We know that proper cognitive functioning depends on a properly functioning nervous system, and that accidents and brain damage can rob people of basic abilities. Indeed, the process of biological aging will do this to some extent. Even if these abilities are diminished by disease, aging, or external trauma, we should still view these individuals as persons because they are indeed still living human beings.
Those who believe in the underlying reality of human nature, in the concept of soul in the Aristotelian or Thomist sense, do indeed believe that a properly functioning brain is irrevocably linked to our proper cognitive functioning as human beings. However, where the Thomists part company with the physicalists is the assumed dependence of the nature of a human being, and hence the human being's worth and classification as a person, on some criteria of optimal neurological functioning. Physicalism tends too much towards adopting a moral theology of imparted worth, a worth decided upon by external functional evaluation (and who does the evaluating?). Thomists hold to a view of inherent worth, of intrinsic dignity according to the nature of the organism.
What we've lost in our common discourse is a foundation of Christian humanism--acknowledging the inherent worth of human beings as persons simply because they are human and created imago Dei. Without this affirmation our society will continue to embrace the equation of the "soul" and personhood with certain cognitive functions while simultaneously suggesting that these functions don't spring from an underlying nature. In the Terri Schiavo case we are observing where such an approach can lead: Trying to weigh the value of a life upon its level of awareness or its behavioral ability--regardless of the species being considered. We are increasingly evaluating people and their worth on "quality of life" and not the kind of living creature that they are. We need to reclaim our human souls.
 In psychology and the philosophy of mind, physicalism refers to the belief that mental states are identical with some type of physical/brain state; non-reductive physicalism emphasizes that mental states might arise from complex brain states, but can't be reduced to these brain states. Neither type of physicalism seeks to deny mental/cognitive states. However, Christian physicalism differs from these approaches by changing "mind-talk" into "soul-talk," arguing that spiritual qualities can be identified with brain states. A recent collection of essays in favor of Christian physicalism is entitled From Cells to Souls, illustrating the pervasive assumption that "soul" arises from "cells." Functionalists examine psychological and neurological processes in terms of the functions or behaviors performed by the organism; monists are those who teach there is only "one substance" in the world.
 The soul is the first and most basic principle of life and unity for a living thing; it is "conjoined with the body, not as two separate and independent entities but as principles, body and soul constitute a living thing with the soul as its principle of life," quoted from James B. Reichmann, Philosophy of the Human Person (Chicago: Loyola, 1985) 233.
 See Warren S. Brown, "Neurobiological Embodiment of Spirituality and Soul," in From Cells to Souls, 58-76; also Warren S. Brown, "Nonreductive physicalism and soul: Finding resonance between theology and neuroscience," American Behavioral Scientist, 45:2 (2002), 1812-1821.
 "The soul is the music made by an ensemble of players (the various lower-level cognitive abilities) who perform together to create the capacities for interpersonal dialogue as well as self-awareness and internal self-reflection (intrapersonal experiences). Played out in relationship to God who chooses to be in dialogue with his human creatures, the cognitive capacity for personal relatedness embodies spirituality." From Warren S. Brown and Malcom A. Jeeves, "Portraits of Human Nature: Reconciling Neuroscience and Christian Anthropology," Science and Christian Belief 11:2 (1999): 139-150.
 J.P. Moreland and Scott B. Rae, Body and Soul: Human Nature & the Crisis in Bioethics (Downers Grove, Illinois: InterVarsity, 2000), 200.
 Brown and Jeeves, "Portraits of Human Nature."
 Lindsay Dewar, Outline of Anglican Moral Theology (Oxford: Mowbray, 1968), 84-85.
 See F.C. Copleston, Aquinas (London: Penguin, 1955); John F. Crosby, The Selfhood of the Human Person (Washington: Catholic University of America, 1996); For its application in biomedical ethics see Scott B. Rae and Paul M. Cox, Bioethics: A Christian Approach in a Pluralistic Age (Grand Rapids, Michigan: Eerdmans, 1999).
 "For most people, 'human nature' is an expression so familiar that it seems to require no further comment. According to a general way of thinking, humans are unique, possessing a distinctly human nature, and for good theological reasons Christians would agree. But some atheistic existentialists and a good many behaviorists are prepared to defend the opposite view. Humans are not unique. . .and there is no such thing as human nature." From R. William Franklin and Joseph M. Shaw, The Case for Christian Humanism (Grand Rapids, Michigan: Eerdmans, 1991), 7.
Derrick L. Hassert is an Assistant Professor of Psychology at Trinity Christian College in Palos Heights, Illinois, and an ordained Deacon in the Episcopalian Church.