Why We Die summary

First, let’s take a moment to define death. How do we know when someone is dead?

You might think the answer is obvious, but actually, the exact moment of death can be hard to define. We used to say that death occurred when someone’s heart stopped beating. But these days, cardiac arrest can sometimes be reversed thanks to CPR.

The loss of brain function is generally considered to be a sign of death, but it’s possible that even this can be reversed. Legal definitions of death can vary from place to place, leading to some strange scenarios. 

For example, there was the case of a girl who was declared brain-dead in California. But in New Jersey, where the girl’s family lived, she was still considered alive. So eventually, she was moved to New Jersey, where she later died. Some might argue she was already gone. But the point is, it’s not always so clear-cut.

Having said that, we can agree on a simple, general definition of death – what we mean when we say someone has died. Essentially, that person is no longer functioning as a whole. Their cells have stopped working together, resulting in death.

Like it or not, death is inevitable. And for most of us, it comes as a result of aging. We can define aging as the gradual accumulation of damage to our molecules and cells. 

Over time, this chemical damage to essential cells affects our physical and mental capacities, until we’re no longer able to function. So, we die. The end.

However, there’s a part of us that cheats death, in a sense – something that has managed to survive for millions of years. Yep, we’re talking about genes.

Our ancestors passed on their genes, and if we have children, we’ll continue the chain. Even though most of our cells die, just as we do, there’s something special about our genes that allows them to outlive us. They become our children, forming the next generation.

How is this possible, when other cells die? Well, the cells that carry our genes are known as germ-line cells. And when these germ-line cells get passed on via sexual reproduction, this essentially refreshes the aging process. It resets the clock, giving the genes a fresh start.

Our bodies are basically vessels, designed to propagate our genes. From a biological perspective, the death of a human is just the death of the vessel.