The attempts by legislatures, lawyers, clergymen, physicians, and philosophers to define death as the cessation of function of a certain body part (whether heart, brain, part of the brain, or whatever) have been misguided. They are failures in theory, and, as medical science progresses, somewhat likely to be shown to be failures in practice. These attempts show a fundamental misunderstanding of what we mean by death and what medical science is doing when one or more of its practitioners pronounces a person dead.

The legislative concern about what death is, is actually (or ought to be) the concern with when we know for sure death (first) occurs.  This is necessary in those cases where the process of dying is somewhat gradual or where the signs of death are not definitive, especially perhaps in those cases where the body, or parts of the body can be kept functioning mechanically even after death.  It is not necessary in those cases where death results immediately and obviously from some kind of cataclysmic, and clearly fatal, trauma to the body.  Nor is it necessary for knowing a decomposed body is dead.  We do not need to, say, hook up an EEG to a skeleton to know the person whose skeleton it was is dead.  Knowing when death first occurs in the unclear cases is important, in order to know when to discontinue life support systems, when to remove organs for donation, when to pronounce death for legal purposes such as probating wills, etc.

What death is has been quite clear and has not changed throughout the ages; but when death (clearly) first occurs, or when death has (clearly) first occurred, in a person depends to an extent on the power of medical science at any given time, and this is what changes through history as medical science and medical technology improve. It is conceivable that medical science will progress to a point where the concept of death itself will have to be changed, and I will address that at the end of this essay, but at the time of this writing, death is still what it has always been.

Now it is normally thought, even by people who believe in life after death, that dead bodies are no longer able to show that they are associated with any kinds of mental states because they are in fact no longer able to be associated with any kinds of mental states. But whether that is true or not, it is at least true that the dead bodies show no association with mental activity or mental states.  Dead bodies give no hint or sign of being able to think, make decisions, see, hear, feel, or smell anything, have emotions, do algebra, or have any other mental experience, whether they can in fact have such experiences or not.

Moreover, whether death ends any possible disembodied thinking, such as meditation and reflection and/or whether it precludes disembodied continuing perception of the physical world, or such things as dreaming, desiring, or feeling pain, pleasure, misery, sorrow, joy, seems open to question. When one entertains the possibility of life after death, one is not questioning the permanence of physical death or death of the body; one is simply questioning whether physical death also causes or involves the end of all mental life or abilities, not just those associated with and demonstrated by, that body. 

But there is no empirical test that I know for whether disembodied mental activity continues or has ceased, permanently or otherwise, for any dead body; and disembodied or spiritual mental perishing has never been the issue in declaring death or knowing death. Death has always been understood in terms of bodily death -- in terms of a permanently non-functioning body, or at least a non-functioning body for which there is no reason to believe functioning will ever return, particularly the mental functioning (previously) associated (or in the case of a baby, expected to be associated) with the body. And an important aspect of a body's being non-functioning is that it reasonably seems to have no thinking or possible thinking associated with it, even if there is some sort of mechanical assistance to keep organs alive or not decaying. It is not mental death (mental cessation), but the body's incapacity to function, particularly in a way that shows any possible present or future association with mental life (thinking, perceiving, acting, feeling, etc.) that is what we consider death.

The possibility, of course, remains open that some metaphysical or eschatological religious intervention might occur in which bones don flesh and the dead from ages past arise and live again, and if this ever happened we would have to re-think of death as some sort of dormancy rather than as permanent perishing or annihilation of the body.

Death is, and is usually thought of, as the permanent cessation of any possible voluntary movement or activity, or of any self-initiated or self-contained or self-activated movement or activity of the body (except, again, for decay, hair growth, etc.) or of any perceptions, thoughts or feelings that seem to be associated with, or that require, that body. In a sense, the death of the body is significant because it signals, and is a part of, the death of the relationship between the body and the mind (that is, between the body and the mental phenomena associated with that body). Whether the mind (or mental phenomena) is extinguished altogether with the cessation of the body's functions (that is, bodily death) or not, does not need to be known in order for us to say someone is dead. The key element is that the body is thought to be permanently unable to demonstrate any association with any mental phenomena.

In death there is no self-activated heartbeat, brain waves, breathing, speech, motion, display of emotion or display of thinking, feeling, etc. and no known possible re-activation or self-activated resumption of all of them, and in particular, there is no known way to activate or revive any kind of mental phenomenon in association with that body, regardless of whether any of the body's organs can be technologically or chemically activated or not.

Until relatively recently, when a person's heart stopped beating for some length of time, they were thought to be unable to be revived or to revive on their own and were thought to have no possible mental activity then or ever again. Just after medical science learned it could re-start hearts which had quit beating, people whose hearts had been restarted were said to have been "dead for two minutes" or for whatever amount of time there heart had been idle. That, however, is a metaphorical or mistaken use of "dead" or is simply a use of the term "dead" because of a formal legal or medical definition, even though that definition does not involve the essential aspect of death that means when you are dead, you are not "coming back." To ask whether someone who died some time in the past is "still dead" can only be a joking kind of question. To say someone died during surgery and then was resuscitated and is now fine is not to mean they "died" in the normal sense of the word.

(I do not know what to say about a case like Lazarus, said to be dead four days before Jesus is said to have intervened and brought him back to life. That kind of case, however, falls under the rubric of metaphysical or divine intervention, and is probably not too necessary to try to allow for in normal medical or legal considerations about the onset of death. Should such cases occur, they would cause us to re-think our notion of what death is and they would cause all kinds of problems for life insurance beneficiaries, remarried widows, inheritance, disability insurance policies, burial or cremation policies, etc.)

The important, difficult, but entirely empirical question is not what death is then, but when it can be known or confirmed to first occur. When does a person's body first, for certain, enter that state in which it cannot do anything "important" (meaning to include associations or activities involving thinking and perceiving, and meaning to exclude merely nail/hair growth, decay) on its own and can never do anything "important" again, and is starting to decay if left on its own? This is important for the courts, doctors, etc. to determine so that individual organs can be removed which could be put into a different, still living body that will sustain their functioning. It is also important to know so that life insurance rather than disability insurance should be paid, grieving over death begin, funeral services take place, spouses legally re-marry, burial or cremation take place, wills be probated, etc.

The answer to that question is subject to change as medical science improves in its ability to detect important bodily functions and in its ability to revive people from states it previously could not. Because we have discovered there is brain activity without functioning lungs or hearts, and because we have been able to revive people whose lungs or hearts were stopped, we no longer consider someone dead just because they have a non-functioning lung and/or heart. And because doctors and other medical people have neither found any other important activity occurring or being able to continue for long with a "stopped" brain nor have seen anyone revive from a brain whose activity has ceased for a certain amount of time, that criterion for the onset of death is the current one. 

This is not a definition of death; it is a criterion for deciding when death has first occurred. It is the earliest state of non-(self-activity) or of non-(important activity) from which no one has ever known to have revived or been revived. Now one can imagine a day when either a new, important bodily activity is detected (or brain waves too weak for an EEG can be detected by another, more sensitive machine) when an EEG does not detect brain waves, or one can imagine the day when someone discovers some chemical, electrical, or surgical, or whatever, balm or procedure that can get stopped brains or stopped brain waves "going" again (or rendered unnecessary). Should this occur, we would need a new criterion for telling when a person's life is first "gone forever" -- but having one's life be gone forever (in terms of no realistic possibility of important body activities, as described previously) would still be what death is, and it would be the same now as it has always been.

It is hard to believe that desiccated bones dug up from the grave will be restorable to life, or that in fact any body, once it begins to decay substantially, can be resuscitated; but if that happens or could be made to happen, then my definition of death would be wrong, and we would need to reconsider all our behavior relating to death. Or death would have happened only to those unfortunates who had such catastrophic accidents that nothing of their bodies is left to resuscitate. 

But at this point in time there is no need to worry about what death is or whether it could be overcome in terms of physical resurrection, resuscitation, remedy, or revitalization of those long thought dead. We only need to be concerned with the question of "At what stage is it from which no one's non-functioning body has ever been resuscitated, nor has been known to spontaneously recuperate, and from which there is no reason to believe it can revive or be revived. At whatever stage that is with regard to medical technology and knowledge, that is the criterion at that time, and should be the legal criterion, for telling when death first has occurred. Instruments may not have to be used to ascertain that state has occurred, if it is known that the state coincides with more visible phenomena, such as decapitation or even the last breath of a long-suffering cancer patient.

Notice, that there is possibly a difference between knowing when death has first occurred, and its actually having first occurred. Suppose that some people have had brain waves spontaneously re-start after five hours of flatline. That would mean, one would have to wait at least five hours after brainwaves flatlined in order to know whether the brain would re-start or not. Suppose that in a given case it does not restart. One would pronounce the person dead at the end of the requisite period of time, but it is reasonable to believe that the person actually died the second his brainwaves stopped, since they were not going to re-start. We just have to wait the requisite period in order to know whether he had suffered irreversible brain cessation or not. When a doctor is frantically trying to revive a stopped heart after other members of a medical team say it is too late, they are disagreeing about whether they know for sure at the time that the patient is dead -- "gone forever". The doctor still trying to save him is not saying he is not dead; he is only saying he may not yet be dead -- that we do not know yet whether he is dead or not. To pronounce a patient dead is to say at that point we know his body is not coming back to functioning in the requisite way and cannot be brought back to functioning in that way.

Similarly, I think, but I am not wedded to this, if there is absolutely no access to medical assistance of the kind that might restart body functions, the person is dead once those body functions cease, even though they could be, or could have been, theoretically re-started under different conditions.  This is true whether the conditions for resuscitating the body are distant in either time or space.  I think I would want to say that a person whose heart stopped in 1850 and was unable to be re-started then was dead at that time, even though he could have been saved in 2002 if he were within reach of the right medical care and were in that same condition. 

However, the safest way to think about cases where someone gets into a condition from which they will not actually be revived (say, because no one is around to help with the proper knowledge and/or treatment equipment) but where they could possibly be revived if they were in a modern medical center is to say there are two meanings of "death": 1) the one I have been discussing, that a person is dead when even scientifically theoretically they cannot be restored or spontaneously revive, and 2) a person is dead when they cannot be revived in practice (or in actuality) even if scientifically theoretically they could have been revived under the right conditions.  Therefore a person who went into cardiac arrest in 1850 no matter where s/he was, "actually (or pragmatically) died" at that moment, as does a person who went into cardiac arrest in 2015 while all alone in a remote area where no one would come upon their body for a week.  But in both cases they were each "theoretically not yet dead," since there are now known ways to revive them under the proper circumstances.  Since the concept of death for thousands of years had no reason to make this kind of distinction, since there were no scientific, medical ways to revive people from a stopped heart (or possibly even stopped breathing), there is no point in trying to choose one of the two meanings over the other as being "the real" meaning or definition of death.  We can say the person in the remote area "actually died the moment s/he went into cardiac arrest" and/or s/he "theoretically died four (or five or however the longest known or scientifically theoretical revival time is) minutes later".  Or we can say, as I do above that s/he died sometime between the time of practical death (moment of cardiac arrest, in this case) and theoretical death, but we don't have a way to know when, because we don't know when or whether they could actually have been revived even under the best medical treatment circumstances.

Watching the show, one had no difficulty "suspending belief" in order to see the couple as either Captain Kirk and crew member or as male and female alien scientist, depending on which mind was in the body at the time. It, of course, sounds stupid to try to summarily describe all these things in words, but when one is reading the story or watching the episode, the concept of a person's changing bodies or of being in a different body is quite clear. In short, the person and the body of the person can easily be thought of as two different things, though in real life, we would not talk that way or have any use for talking that way. So far that concept is relegated to fiction, but there is at least the theoretical possibility that science could allow persons to change bodies. If so, as I describe below, that will necessitate a new concept of death, which I will also discuss below.

The notion or concept of death I have described above involves essentially the death of the body of the "person" who is dead. And this has to do with the impossibility of that person's thinking, feeling, perceiving, etc. being associated with that body. In other words the person's body will show no signs of mental activity or the possibility of its return. 

Suppose, though, that there is some part of the body (presumably the brain or some part of the brain) that is integrally associated with thinking and perceiving, with memory, etc. and that someday science finds a way to transplant this body part (let us just assume it is the brain to make speaking of it easier) into another body whose brain has been removed. (The brain might be also preserved in a machine, such as a mechanical, robot-like, body, or if put into a host human body that body might have two brains after the transplant. The specifics of the physical aspects of this may vary, but the conceptual issues I am about to raise will still be about the same, I think.)

Until and unless the day arrives for such a transplant, I think everything I said earlier is true. But if that day does come, there will be new conceptual problems I will now begin to discuss, but I think those can be resolved. 

The initial problem is this: Suppose we have two people, Abe and John. Something happens to Abe's body such that it is near the end of its life. Up to the time of the possibility of a brain transplant, this would mean that Abe is about to die. John, in the meantime has something severely wrong with his brain, even though the rest of his body is perfectly healthy. Abe's body dies at the same time that John's brain quits emitting brain waves for the requisite amount of time to determine legal death, and doctor's now transplant Abe's brain into John's body. (Technically this could be considered either a brain transplant or a body transplant, but we typically would say it is a brain transplant.) 

To begin with, let us assume that when this "body with the different brain" wakes up, "it" (or the person "in it") identifies himself with Abe. When asked his name, he says it is Abe. He recognizes his wife and children and says how happy he is to be able to still be with them. He can name all his grade school teachers and he starts telling strangers some of the stories that he has been telling for years. He asks for his favorite food, which is the same favorite food Abe always asked for. In short, we would say this is Abe and Abe is still alive. Abe might look different, and might even look like a twenty year old (if John was 20), and his friends might not recognize him or believe it was him, but this problem is not much different than if he had lost a lot of weight, got in shape, had a hair implant, had a face lift, dyed his hair, etc. As time goes on, his friends would easily come to recognize him again, and might even eventually forget he used to look like the old Abe. In short, this is Abe.

The problem this presents for my criteria above is that because almost all of Abe's (old) body is gone and is no longer associated with Abe's thinking, and John's (old) body is still functioning but is not associated with John's thinking, though it is associated with mental phenomena, Abe ought to be dead, and perhaps John might not be. Then, because clearly we would all say the above person was Abe and not John, we would need to amend the definition of death to take this sort of thing into account, and being dead would be that state in which a person's thinking is no longer associated with any functioning body or machine that gives an indication that person is still thinking/perceiving, etc.

But that would work only if John's body wakes up thinking it is Abe, and essentially has those kinds of traits that are able to convince everyone it is Abe. If it does not work out so cleanly in that way, then we are on new conceptual ground, though fiction and science fiction has explored this new ground to some extent. 

Normally there are two aspects to being the same person, one mental, one physical, and these two aspects normally "go together" in some sense. People's minds do not hop from body to body. They "stay with" the same body. You don't wake up one day being someone else; and, as John Locke once noted, wherever his body goes in a coach, so does his mind seem to go with it. That is, of course, while he is alive.

But even in the normal case, conceptual problems arise if one were to think about them. The mind and the body each change through time. It is just that the change is normally gradual enough that we still identify someone as being the same if there is considerable overlap between sets of memories through time (for the mental part of identity), or if there is considerable overlap between body cells through time. Let me explain.

Mental identity: normally we do not need to look in the mirror and match the image with an ID card in order to know who we are. We wake up in the morning, and no matter how we feel or how we look, we know it is us. If suddenly we developed some physical change, as in waking up after an automobile accident and the ensuing surgery, we would wonder what happened to us, but we would not doubt it was us that it happened to. And apart from amnesia cases, we would know who we were whether our body parts were radically different from what we last remember or not. It is not our physical bodies that tells us through our own thinking who we are.

Some philosophers have thought it was memory that let us know who we are or that kept us being the same person through time, but clearly we forget lots of things we have done in our lives and that does not mean it was not we who did them. And sometimes we "remember" or feel like we remember for certain having done something that we actually did not do, but that does not mean somebody else did those things. I will not talk about amnesia here because I do not know what the experience of the amnesiac is. I do not know whether he thinks he just can't remember anything about himself, or whether he does not even know he had a prior self that he worries about trying to remember. I am not sure what the amnesiac is actually seeking if anything. Normal sorts of memory loss and memory experiences will suffice for the points I want to make here.

It is possible that our memories overlap such that if at any time, we have say, ten thousand possible memories of events in our lives, if in 1995, 9,000 of those were the same as the ones we had in 1996, and 9,000 of those were the same we had in 1997, then that might be what leads us to think we are the same person in 1995 as we are in 1997, even though perhaps two thousand memories are missing or different. If we continue this over the years, none of our memories at one year in our life might be the same as those of thirty years later (which happens to us when we go from age one or two to age thirty one or thirty two), but we will be the same person because each day we were the same person as the day before with regard to memory overlap.

That can explain how we can be the same person over time though we forget lots of things over the years, but I do not think that is how identity works "from the inside" though because I do not think I have to "remember" who I am when I get up in the morning. I just sort of "know". And if I sleep in a different room, so that when I wake up, I don't see anything familiar, or if I wake up in the night and get out of bed and walk into things, I only wonder where I am, not who I am. Even in those cases where I have drifted off to sleep, and the phone rings in a way that wakes me up totally confused about what the noise is or where it is coming from, I do not wonder who I am, and I do not have to search through any memories that I know of or get out my driver's license or look in the mirror. I have sometimes awakened in the middle of the night unable to see familiar lights or to see the lighted dial of my alarm clock, which is usually near my face on the night table, and I have then thought the power must be off or that I am not where I thought I was, but even then I have not had to wonder who it was that was pondering all this. 

Physical (body) identity: other people, of course, identify us through our physical features, typically since they are not directly privy to our thoughts in the same way we are. When I see my wife in the morning, I know who she is by certain similarities of features, or the sound of her voice, etc. If she looked like someone else altogether, she might know she was her, but I wouldn't. Not at first, at any rate. She might be able to convince me it is she, if she correctly answers questions I ask her that I think a stranger would not know.

However, over time physical features change, often so much that it is difficult to recognize someone you knew in their twenties now that they are in their sixties or seventies. Surely old people do not resemble the babies they once were. But again, overlap of body cells and features from one day to the next keeps that from being a problem for those who are in contact with each other over time. The two year old looks sufficiently like the three year old to be recognizably the same person. The three year old looks sufficiently like the four year old to be the same person, so then that makes the two year old be the same person as the four year old, even if they look quite different.

But twins are still not the same person even though they may look alike. And clearly, innocent people are often misidentified as criminals by eye-witnesses, so similarity of appearance is not the total way we identify others even by sight. The mother of newborn twins, or at least the hospital nurses, might leave the baby's identification tags on them for some time. We might identify someone through fingerprints or DNA. We might identify someone we see get on an express elevator as the person who gets off of it simply because they look like them and the elevator did not stop anywhere in between. We identify people by behavioral quirks and the sound of their voice, their accent, their cadence, their phrasing, etc. In the dorm we could often identify people outside our rooms by the sounds of their footsteps. When a sufficient amount of these things coincide to point to a person's body on one occasion as being the same person's body on another, and there is no evidence to the contrary, we reasonably believe we are seeing the same person on both occasions. 

But all this will be problematic if brain transplants do not seem to yield either person as the survivor, or if they do not result in one of the two being clearly the survivor. In a Doonesbury cartoon one time, a Texas rancher receives a heart transplant from an up-East liberal intellectual and, after recuperating, orders himself a thick, juicy steak, rare, but surprises himself by asking for red wine with it. Suppose that after a brain transplant the survivor has traits and memories of both people, or of neither. Or suppose that a man's brain is transplanted into a woman's body, or a short person's brain is transplanted into a tall person's body, or an unattractive person's brain is transplanted into an attractive person's body. There are lots of possibilities, and with many of them, the resulting survivor may be radically different from either of the two original people involved. The same might be true for someone undergoing a sex change or any serious surgery, who then also develops memory loss or partial, but significant, memory loss. 

People also "change" from highly emotional or traumatic life experiences, where they, and everyone around them says they are no longer the "same" person they used to be. To some extent that is just a figure of speech to indicate they think and/or behave very differently from the way they used to. But we could have said, or we could say, if we wanted to that the change is so complete that what is left of the old person is not enough to say that person still exists, even if we do not want to say that person is dead. We might say we have a whole new person. As long as everyone understands the circumstances and why we are saying that, nothing is lost. It would become a legal and commercial issue then as to whether insurance policies should have to be paid off, new passports issued, death certificates issued or missing persons reports filed, divorces granted or not, etc. If your husband has a sex change operation, do you need a divorce for him not to be your husband? The courts or the law could decide that either way. They could say it is automatically grounds for immediate divorce, or they could say no divorce is necessary. There could be a special category for women whose husbands have sex changes, something somewhere in between being divorced and being widowed. This is simply a case where science has made something possible that is so radically different from our historical concepts, that we have to fashion a new concept to categorize it. We are free to do that, within some reasonable boundaries, however we would like. It is like asking whether some new vehicle out of Detroit is a car or a truck when it has features of both and is missing features of both. It requires either a decision by fiat or it requires a whole new concept and designation. There is no "natural category" or "natural" way to decide.

At what point in episodes of this sort, either in real life today, or with the advent of some future transplant technology, would we say that we have a new person and that perhaps both of the original people are dead, or at least gone. Or if we are unwilling to say both are dead, which one is the one that is dead?

There will not be a natural answer to this, because the concept of identity -- of being the same person as one was before -- doesn't apply in these kinds of bizarre cases. Even if we look at something like a plant, there are conceptual problems if we cared whether something was the same plant or not. Suppose we take a shoot off an old plant and grow it. It was part of the original plant and it is genetically identical to the original plant, etc. But it is not the original plant, or is it? Suppose we take part of the original plant and kill the rest while saving the part we are interested in to generate a whole new healthy plant? Is it the same plant or a different plant? Is the original plant dead or still alive? The concept of "the" plant is simply not clear; we don't talk about it that way or think about it that way. We talk about parent plants and off-shoots, etc. but we don't think or talk about whether it is the same plant or a different plant. If we do happen to say one plant is the same as another, we usually qualify that by explaining it "came from" the other plant as a shoot. The concept of "identity" just does not apply one way or the other.

Even in the cases of inanimate objects, the concept of identity is somewhat arbitrary. I am writing this in the year 2002, and I met a man last week who has a 1948 Ford truck, a hot rod, that he shows at auto shows. He has restored "it" to mint condition. I put "it" in quotations because suppose almost every part has been changed out at one time or another. The only thing that would make this truck "a 1948" Ford is that it or something from which it evolved, started out as a 1948 Ford truck, looks the same as a 1948 Ford truck (that is, has the same style or appearance), and the parts overlapped through time with parts that were the original parts or with parts that overlapped with the original parts, etc. This truck even has power locks, power windows, and air conditioning, none of which the "original" truck had. Yet it is, in some sense, a 1948 Ford truck, and in some sense it is "the" 1948 truck that belonged to some first owner in 1948. 

Further consider also that this gentleman told me that his truck has a Ford engine in it, but that many restored Ford automobiles have Chevy engines because Chevy components are easier to get than Ford components. Well, how much of a Ford can be a Chevy and still be called a Ford? Surely that is some arbitrary amount, though not completely arbitrary. The car or truck, would have to still look like a Ford, I presume. But that cannot be the only requirement, for if we take a Chevy and put Ford body parts on it until it looks like a Ford, we would presumably still call that a Chevy -- either a "Chevy with a Ford body" or a "Chevy that looks like a Ford." 

The same might apply to people if transplants occur that make us uncertain which, if either, is the survivor of the merged body parts. We will then have to make some kind of choice of whether to say one or both of the original persons died, or which one died. We will have to choose which to say survived, if we want to say either did. Either way the choice will be somewhat arbitrary and we will have to change our concept of death. But until and unless that happens, the concept of death as I explained it at the beginning of this paper is, I think, the concept we have had in mind for millennia, and death has not changed, even though the criterion for when death first occurs, and the criterion for knowing when death first occurs, in some cases has changed as medical science has advanced.