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What is death?

  1. Oct 28, 2004 #1


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    From a biological point of view, when can a human be considered dead? after brain activity ceases? after the heart stops? after all human cells cease metabolic function? If a human brain were to cease functioning, but the body is kept going on a life support macine, with all basic functions still working, can it be considered alive (compare to a headless chicken)? Can a person be considered dead if a doctor could still revive them through whatever means?

    any thoughts?
  2. jcsd
  3. Oct 28, 2004 #2
    I consider death the inability to become conscious. As for what defines concious, you might have to peak into the philosophy section of these forums.
  4. Oct 29, 2004 #3
    A body is made up of cells. When the cells cease metabolic function, and stop working, they die. If all cells die, then a human is dead. Simple.
  5. Oct 30, 2004 #4


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    so when you behead a chicken, and it keeps on running due to reflex reactions, you still consider it alive?
  6. Oct 30, 2004 #5
    That isn't a simple question. Currently, death is used to design brain death. Transplant donors can be supported "alive" but in brain death until the organ extraction.
    Near death experiences have been reported in situations of death reversed by a medical action. But in this case, death obviously has not ocurred. Death is associated to irreversibility.
    Of course, the death concepts were changing with advances in Medicine (actual reversibility of previously irreversible conditions, diagnosis of brain death versus heart arrest...)
    A lot of our cells are living after brain death. It is a question of time. When cells lack oxygen and nutrients by absence of blood circulation, they die.
  7. Oct 31, 2004 #6
    Yes, a chicken is still alive, until it stops moving completely, and all its cells cease metabolic function.
  8. Oct 31, 2004 #7


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    Consider this. Assuming death means irreversible loss of function, brain death is a really bad thing. It probably also means 'you' don't much give a rats mule about what happens to the support mechanism after that.
  9. Oct 31, 2004 #8
    When production of ATP ceases.
  10. Nov 3, 2004 #9
    If so, there is a lot of people buried when they are yet alive. :frown:
  11. Nov 15, 2004 #10
    Imagine if in the future(this might seem a bit sci-fi here) we can live in this world as disembodied lifeforms, capable of transferrring from one body to the next or having bodies made for us to replace the old ones. Then how would we define death? If the cells in our physical bodies die, we can simply transfer to another shell like hermit crabs. Or perhaps we can have our minds, souls, spirits, or however you would like to put it transferred to an inorganic mainframe or personal quantum brain unit as described in the book, Schild's Ladder. This is definitely more philisophical than scientific of course, and some people already believe in a version of this ideology today, known commonly as reincarnation. This version would not be quite the same though, because I'm saying that we wouldn't actually have to "die" to switch. If this were true or conceived as possible in some way, then we would have to seriously reconsider the very definition of life, consciousness, and existence in general. Some people I know, believe that our brains are what make us who we are. For instance, if our brains were capable of being transplanted into other bodies, then we would still be ourselves, right? It reminds me of the cartoons where people switch heads and can move their own bodies but are seeing through their eyes on top of the other person's body. It is a rediculous notion of course, but it serves as a grounds on which to ask: what makes us who we are and what makes us alive? Can we exist outside of our physical cellular, embodied selves? If so, then do we really die when our bodies cease to function and our cells decay? I am treading in both philisophical and religious territory here, I know, but these two aspects of human thought are inevitably linked together with science, so involving them (carefully at times) can prove to be important and necessary, esp. in life science. I just wonder how well any of us, including myself, truly understand what life is. o:)
    Last edited: Nov 15, 2004
  12. Nov 19, 2004 #11
    the meaning of death according to modern day medicine is the where the human is in a state such as where they cannot regain concienseness (or hawever you spell that word) and the brain is deprived of oxygen for more than 20 minutes even if the doctors can do certain procedures that would keep the organs alive. i consider the human to be dead when they are brain dead and so can not operate themselfs but rather rely on a life support machine and so can not (in want for a better word) live.

    a day without sunshine.........is like............well.................night
  13. Nov 19, 2004 #12
    in response to muon12 i believe you arte right in some aspects i'm not going to go into a huge argument on this subject because it is not neccesary. i myself am a christian and for obvious reasons this will affect my judgement but please bare with me on this cause. according to my beliefs we are able to live outside of our body but not to transfer bodies but rather as a spirit state not like a ghst or anything but a body within a body if you like. we are living in tempory world whether we like it or not
    God created and God can take away and he says that he will. this may seem strange but i beleive that our life on earth is just the beginning of something huge, the warm up before the match if you like none of us really do understand what life is but i do know why we are alive. in fact when we die i beleive we are more alive than we have ever been as life goes on death is just the door to a new life. but unfortunately there are two doors and not all of us go through the former but rather through the door that leads to hell. why u may say well our time on earth is like a test not a test we need to pass but a test we need to realise and take actions because of it. we cannot get in to heaven because of our actions but rather our reactions to god.
    there is a fine line between religion, science and ethics but i think that in someplaces the lines cross over and so rules apply to several areas but it is lines that we need to see and realise.
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