Modern medicine defines death in several ways. There can be cessation of heart beating, cessation of breathing, or cessation of brain activity. The latter is intended to be defined quite clearly so as to not include people in comas that may potentially wake up.
Heart death is when the heart stops pumping and electrical activity ceases (asystole, flat-lining). A heart may stop beating but the electrical activity continues. This may occur because the heart cannot pump (pulseless electrical activity) such as when there is no blood (bleeding), or nowhere for the blood to go (clot in the lungs), or no space for the heart to contract (blood around the heart). It may also occur when abnormal electrical activity does not cause heart contraction (ventricular fibrillation). Both these situations very rapidly become asystole if not treated, and frequently even if treated, especially when death is expected.
Cessation of breathing, eg. blocked airway or drowning, leads to a rise in carbon dioxide in the blood and decreasing oxygen. Increased carbon dioxide quickly leads to unconscious and acidification of the blood. The heart stops after a few minutes (unless there is severe hypothermia) for various reasons.
Brain death is defined as no electrical activity of the brain, no brain reflexes, no response to a stimulus. The person cannot breathe independently, and sometimes cannot maintain a heart beat; thus such a definition exist because of advances in medicine allowing prolonged mechanical ventilation.
These definitions of death are somewhat reasonable. Nevertheless we need to consider what Scripture may say to the issue and whether that modifies our thinking around physical death.
The Bible has several references to various organs of the body. Kidneys, intestines, eyes, liver, skin, blood, bone, heart. Several of the occurrences are literal when describing sacrifice: what to do with the kidneys or liver when offering sacrifices to God. Several are metaphorical, though different to the metaphors we use in English. Thus translators may use English metaphors, though some have become English metaphors from the Hebrew via the English Bible.
"Kidney" (
kilyah) may represent emotion. Consider Jeremiah 17:10a
“I the LORD search the heart (leb)
and test the mind (kilyah), (ESV)
I, the Lord, probe into people’s minds (leb).
I examine people’s hearts (kilyah). (NET)
"Kidney" appears on the second line, translated "mind" in the ESV and "heart" in the NET. "Heart" (leb, lebab) in the Hebrew apears in the first line. The ESV retains heart whereas in the NET it is translated as "mind". The NET's translation of "heart" as "mind" is not without justification as "heart" often carries the connotation of "will" in Hebrew, whereas it tends to reflect "emotion" in English.
me`ah means intestines or other internal organs such as stomach or uterus (also
beten). Literally Psalm 22:14 reads:
I am poured out like water,
and all my bones are separated;
my heart is like wax;
it is melted within my intestines (insides);
The relevance of this to our discussion relates to the word "blood". Blood represents life in Hebrew. The question is whether this is primarily metaphorical, or symbolic, or whether blood is perceived as the source of life. "Blood" (
dam) occurs over 300 times in the Old Testament. It is clearly used at times when "life" (
nephesh) is meant. As such it has a figurative use. Though I am inclined to think that this is because the association with life is meant to be a literal one. After the Flood God instructs Noah concerning food and death:
But you shall not eat flesh with its life (nephesh), that is, its blood (dam). And for your lifeblood (dam nephesh) I will require a reckoning: from every beast I will require it and from man. From his fellow man I will require a reckoning for the life (nephesh) of man.
“Whoever sheds the blood (dam) of man,
by man shall his blood (dam) be shed,
for God made man in his own image. (Genesis 9:4-6)
God tells Noah that meat has to be drained of blood because the blood
is life. In verse 4 blood is identified with life in a
definitional manner:
"Life" and "blood" are also juxtaposed in verse 5 which is translated by the English word "lifeblood", or alternatively "blood of your life".
Another consideration in understanding death is the word breath. Breath (
neshama) and breathe (
naphach) are used in the creation account.
then the LORD God formed the man of dust from the ground and breathed (naphach) into his nostrils the breath (neshama) of life (chay), and the man became a living (chay) creature (nephesh). (Genesis 2:7)
Though there is a connection between breath and life here, it does not seem to be as strong. The breath (spirit) of God is required and it is the breath of life, ie the breath that causes life, but it is not definitional. The breath itself is not identified as the life itself (even though it is the source or cause). An argument can be made for an association between breath and life, though I think it less convincing than blood.
The association of blood with life in Scripture provides us with material to deduce a biblical definition of death. If we accept that blood represents life, or is life, then the complete loss of blood or the cessation of blood flow is a coherent biblical definition of death. How does this correspond to current medical views? We know that cessation of blood flow is due the heart ceasing its function as a pump. Therefore a medical definition of cardiac death as asystole is equivalent the biblical definition of death. The Bible would also allow the loss of significant blood from bleeding, pulseless electrical activity, and ventricular fibrillation as definitions of death, though without medical intervention these situations very rapidly become asystole.
Biblically, death is the loss of blood flow, that is the non-perfusion of (all) organs with blood, this is usually due to the cessation of cardiac function.
If we were to argue that breath also relates to life, a secondary biblical definition of death is cessation of breathing, which incidentally leads quickly to cessation of blood flow, our primary definition.
Brain death is not primarily a biblical definition of death of itself, other than that it involves lack of ability to breath spontaneously.
This leads to some interesting conclusions. It should influence how we think about sentience and life. It may have implications concerning euthanasia, abortion, organ donation, mechanical ventilation and other supportive therapies.