This essay was one of the first posts put together—not involving ghost hunting—for the Mad Ghoul project in the early 2000's. It is very short, and not much more than a Wikipedia entry, but was a turning point away from first person experience towards more research narratives. It is dated here from roughly its original date. It was later republished on Key 23.

Quantum physics has become a gem among sciences for every philosopher, whether contemporary or esoteric. The oddities of quantum physics have bent perceived reality into a new direction formerly only occupied by science fiction. The reasoning developed to explain quantum anomalies has resulted in fact being far stranger than fiction, and many theories have come about that contain astronomical implications.

Quantum suicide and quantum immortality are just such theories.

The Everett Many-Worlds interpretation of quantum physics attempts to explain the connundrum of the Schrodinger's Cat experiment, and the anomalous "nature" of quantum particles, by theorizing that every time a decision is made, the universe splits into two parallel worlds—one for each decision. This means that all outcomes exist. In the example of Schrodinger's Cat, this means that when the gun goes off, the world splits, with one branch carrying on as if the cat had died, and the other carrying on as if the cat were still alive.

What makes the quantum suicide thought experiment different is that it is seen from the perspective of the "cat in the box," so to speak. From this perspective—if the Everett Many-Worlds interpretation is correct—the cat will only be aware of the split world in which he lives. No matter how many times this Russian Roulette experiment is played, he will only be aware of himself surviving the experiment, because he cannot continue to observe the experiment once he ceases to exist. In fact, from his own perspective, it will seem as if he never dies.

This evaluation from the perspective of the cat in the box, directly leads to the theory of quantum immortality, which speculates that a conscious being cannot cease to exist. The idea is that regardless of the probability of the outcome, and regardless of the observations of those around the experiment, if the Everett Many-Worlds interpretation is correct, there must be a small subset of universes where the cat sitting in the box in front of the gun will live. As such, the cat will only be conscious of that outcome, since his consciousness only remains in the universes where he does not die.

The highly controversial conclusion to quantum immortality, is that if the Everett Many-Worlds interpretation is correct, then from the conscious observer's perspective, they will never cease to exist.