"The trigger of death, in all cases, is lack of oxygen. Its decline may prompt muscle spasms, or the "agonal phase," from the Greek word agon, or contest." That is the literal explanation as to why we die. http://www.discover.com/issues/sep-06/departments/20thingsdeath/

(Why? or How?) i heard a response to that question just recently on a preview for the tv show Six Feet Under. i'm not sure the exact wording, but it was something like this: "to make Life matter."

Everything has a life cycle, Even the planets. The Sun will explode in a couple of millions/billions of years. Even glass, it takes glass one million years to decompose. Nothing can last forever.

There are lots of ways to answer this question. From a biological viewpoint, our body's cells gradually lose their ability to regenerate our organs properly, and eventually some critical system will fail and cause death. There is some pretty complicated research going on regarding exactly why the cell-reproduction mechanism deteriorates over time. Of course, this only covers death from "old age". There are lots of diseases and accidents which can cause what might be considered "premature" death.

The real answer to "why do we die " is this. God made the world and he made man in his image. Adam and Eve were the first wo people made. They were in perfect peace with God, the creator. At that time death was not heard of ,it did not exsist.They lived in the garden of Eden. God told them not to eat of one specific tree. The devil was also a created by God. He came to Eve in the garden and told Eve to eat of the tree that God told them not to eat of. Eve ate the fruit of the tree and disobeyed God. At that moment death entered into the world because of mans disobediance to God.And death has been passed down through all generations. What was normal in the beginning is strange and abnormal to man now. Now man denies God and denies the bible and has gone so far from the truth that we don't know what is true anymore. Sweet fellowship that man had before with God has been broken and we are now born spiritually dead. God wants to restore that fellowship with each person because he made us and loves us. Our own ideas and philosophies have lead us to now reject our own creator. The good news is that that fellowship can be restored and we can become spiritually alive again by accepting Jesus as our savior. God has stomped on death and when we become alive in Christ death has no reign on us anymore! Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned: (Romans 5:12) That as sin hath reigned unto death, even so might grace reign through righteousness unto eternal life by Jesus Christ our Lord. (Romans 5:21) That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved. (Romans 10:9) dont take mans word for it take God word!

There is a simple engineering rule: the more complicated something is, then the more likelihood there is that something, somewhere, will go wrong. Life (in the purely biological sense, not the philosophical sense) is incredibly complicated. It also accumulates wear and tear, as any other material component of the universe does, over time. As damage accumulates, repair mechanisms get less efficient as well, which feeds back as more unrepaired damage. Eventually something gives, and the system collapses; when the complex interlocking systems which make up "life" fail like that, you die. Death is inevitable in other ways, as well. If nothing died through wear and tear, but things (or people) still reproduced, then eventually there would be so many individuals competing for so few (in comparison) resources, that many would simply starve. And if you counter with the idea that individuals could live forever but not reproduce, you should remember that the variation introduced by reproduction is what allows life to meet changing physical conditions; out of all variation, there are generally a few who can survive changing physical conditions the best. If that process didn't work, then every time the planet underwent a drastic change (say, an ice age), then just about everything would die from not being "fit" for what they have to deal with. Death allows continued life.

Biology and religion aside, maybe a purely philosophical way to look at it would be that death "validates" life. Without death, life would not be special because there would be no alternative to it. Just like it would be impossible for us to be happy if we did not understand and occasionally experience unhappiness. We need the two contrasting opposites to give meaning and perspective to one another. The same is true of life and death.

every thing has an opposite therefore life is to death as light is to dark. sort of like what freef4life79 said. but in a semi-nonreligous way, no offence (i'm christian)

because we are biological organisms. we are born, therefore we must die.

cause shit happens

That's just the cycle of "life" ... we're not immortal.

If we didn't die the world would become overpopulated and there literally wouldn't be enough room to hold all of us. Unless of course everyone turned cannibal like me!

B/c holy Jeebus would the world be overpopulated if we didn't

Our organic bodies are pretty delicate and can't stand up to many years of environmental abuse, even in the best condition. Like all machines, we just wear out.

because if we didnt die life wouldnt be worth living

If we did not die, then the world would become over populated - and all the population would be very old and probably quite infirm. There would be no room for anyone else - so ...er.. sex would have to be banned - so that no new people could be created - so, basically, we die so that others can have sex.

To renew live for someone else- besides getting really old sucks.

To keep the Tax man happy! :-/

nothing can last forever..and c'mon you really want hitler still alive & kicking?

We must die because we must save us.

Because we live.

so that our children can experience a life without overbearing parents like us! no, not really. we die so that we can experience something great, something far better than what we are living now.

Unless we die, our siblings cant live in this world. Coz human cannot occupy a permanent space in this world. If Birth is beginning, Death is End.

We die because what goes up must eventually come down.

Don't think of it as death, think of it as nivarna! :D

we have to die in order to avoid the suffering of the world.

Because I said so... now go to your room! :)

Life would be taken for granted if we didn't at one point die. Nobody would care what the consequences to anything were. It takes some people the moment before they die to realize that life is great, but as they say better late then never. Life is short, make the best of it. Dying is a way to pass ideas on to the next generation, a way of starting new.

We don't "die" but we do move on. We came here to experience, loss is but one of those things.

Who says we die? Our bodies wear out, get sick or destroyed in some accidental way, but our bodies are not us. We live inside our body, an eternal soul using our body as a vehicle here in this life. Its like your house. You live inside your house, but if your house caught fire, you would leave your house. You would still be there, but your house would be gone. See? After your body is dead and gone, you will just move on to a different dimension of the universe probably, and who knows? It might be a lot nicer and better than this one, assuming that you learned some life lessons during this life, and are then able to move forward to the next dimension.

to live we must die. if you don't want to die then don't live. living and dying are like two sides of the same coin.

Because all matter in the universe is in a state of degradation. Even if we were 'immortal', we would eventually 'decay' because the atoms in our bodies would break down. Sure, that would take many many trillions of years, an incomprehensibly long time, but it would happen.

could you imagine how crowded things would be if everyone didn't have to die? how much MORE issues there would be with healthcare?

Because matter can not be created nor destroyed. If we all continued to live the entire cycle of life would be thrown off. We must die to produce energy and matter for other beasts to consume. So that we can be nourshied and go on to create new life and die. (thats just my opinon though)

So that we can be born again.

because we are controlled by nature, if we couldnt die then whats the point of living? you would take everyday for granted if you knew it would just go on.

To make space for others.

I think I'd get bored being in the same body, doing the same thing for eternity... I have ADD, I need change and ... Oh look butterfly

To understand that life is a limited thing, and that we must enjoy the time we have rather than waste it.

We are pre-programmed to self destruct after we procreate. We do this to give room and resources to the next generation and the ones to follow that. There is nothing "mystical" in death - you have simply completed your life's mission and now it is time to be cast aside.