From the dawn of mankind, the peoples of the world have questioned what happens after death. Although some feeAncient Egyptians immortalityl that it is a permanent end, some religious beliefs such as those of the ancient Egyptians and the Christians, hold that there is an afterlife, and that when we die, we are transcended. Other religions, such as Hinduism and Jainism, hold that we are reincarnated as something else after our deaths.

This article brings to light another possibility: that we cannot experience death.

Introduction to quantum immortality
I'm sure you're quite excited to see how it's possible we could technically live forever. But, before we begin discussing what quantum immortality is, let us preface this with some basic information about the physics of immortality. I am by no means a quantum physicist, and will thus only describe the Quantum immortalitybasics of the highly complex world of quantum mechanics. As you may know, an atom, the basic building block of all things around us, is composed of a nucleus with electrons hurdling around it. Werner Heisenberg postulated that it was impossible to know both the direction and the position of an electron at any given time, and this has thus been coined as the uncertainty principle.

Heisenberg believed that everything in nature is in a wavefunction of possibilities, and, based on the uncertainty principle, particles' wavefunctions collapse upon being observed. That is, what a particle's position actually is is not determined until you observe it. This is known as the Copenhagen interpretation, and is the most popular interpretation of quantum mechanics.

However, a second interpretation known as the many-worlds interpretation states that, rather than the wavefunction collapsing, the outcome seen by the observer is relative, and the universe at that point splits, where another possible outcome or other outcomes occur in another universe not seen by the observer.

If the latter, many-worlds, interpretation is true, we can then derive the quantum suicide experiment.

Quantum suicide experiment
Let us suppose that a man is holding a gun to himself that is hooked up to a spinning particle. The gun will, at every moment, detect whether that particle is spinning clockwise or counterclockwise. When he pulls the trigger, if the particle spins clockwise, the gun will fire, and he will be dead. However, if the particle spins counterclockwise, the gun will not fire, and he will survive.

The many-worlds interpretation states that, each time the gun is fired, the universe splits into two, one where he dies, and the other where he survives. In the universes where he survives, the man will be unaware of his own death.

Quantum immortality
From the quantum suicide experiment, we can then derive how it would be possible to live forever. Assuming the many-worlds interpretation is the correct interpretation of quantum mechanics, there is always going to be a chance the gun will not fire. The argument for quantum immortality is that the observer will always be able to perceive at least one universe in which he is still alive, and thus that it is impossible for the observer to ever witness his own death.

Arguments against quantum immortality
However, some scientific critics argue that quantum immortality cannot feasibly be true. Max Tegmark, a professor at MIT who helped develop the quantum suicide experiment, argues that people have a conscious decline as they die that makes it impossible to create a smooth transition to immortality from an alternate universe in which the person would die.

David Lewis, a philosopher, takes a less scientific and more cautionary approach to disproving quantum immortality. He stated that an observer who lives forever will most likely find himself in horrible condition. Being unable to die while being horribly disfigured would be miserable, he says, and as such it's best to think that quantum immortality is not true.

Regardless of how "out-there" it is, there is now some scientific support for the idea of how to live forever. Although it may be bizarre and, as David Lewis would say, unfortunate, quantum immortality is certainly something to consider.