I was just reading about some things to do with quantum theory. The theory is way beyond my comprehension, but it gives rise to some interesting speculations and thought experiments, and those I CAN understand.
One of the thought experiments is about multi-dimensional universes. This is based on the idea of Schrodinger's Cat (see the Doomsday Device post). We say that the actual status of the cat is fixed by the observer, in other words, the consciousness of the observer CREATES the status of the cat. In a similar way, as you go through your day, your year, your life, you meet thousands and thousands of instances of having to make a choice. Do I go upstairs or downstairs? Do I take this job or stay in my old one? You have to decide which way to go, and whatever you decide, your consciousness follows the consequences of that decision.
It's a bit like the camera in a movie. Your consciousness, in a sense, CREATES the reality of what you see and experience. The other possible consequence is made to be non-existent because your consciousness has not followed it, has not MADE IT REAL. Up until the time when you make that choice, both of these separate realities have an equal chance of being real. They both have a probability existence, like the cat before you open the box. This gives rise to the idea of an infinite number of universes, branching off from each other, each one coming into existence each second or each millisecond as your consciousness makes the choice to observe it.
The idea of the Doomsday Device brings up another interesting idea. The Doomsday Device experiment tells us that the outcome which leads to no consciousness of any event just cannot happen, it would be impossible. This seems to indicate that there can be no such thing as death, at least as we understand it in its usual sense, because it would cause a PARADOX of having to be conscious of not being conscious, or being aware of having no awareness. So the logical conclusion is that, however things may appear to be, we are immortal, since every outcome of every branching probability is one which leads to conscious awareness. To life, in other words.
But how can this be, since we see and hear of death happening every day? Some have speculated that the event that we call death is the beginning of the event we call birth. They argue that your consciousness at the time of "death" immediately begins to have the experience of birth, and so life continues without a break. If you think this sounds a bit weird, just compare it with the paradox in the previous paragraph.
Some speculations come from this idea. What kind of life would this new one be? Some would speculate that it is the same life as before, but with the capacity to differ from the former one because consciousness may make different decisions at certain points, thus creating an entire different universe of experience. One can visualize this repeating itself endlessly over an infinite time, so that your consciousness eventually experiences everything possible. Under this model of the universe, or Universe of universes, life would not be dull.
Credit must here go to Nietzsche, who was probably the first to speculate on the idea of a cyclic model of conscious existence. But Nietzsche did not have the predictions of quantum theory at his disposal, so the best he could come up with was to say that when you repeated your lives over and over again eternally, each one was EXACTLY the same as all the others. A bleak prospect, and one that would indeed be dull.
A consequence of the consciousness-chooses-life philosophy is that, since you are immortal, it follows that you need have no fear. One imagines that if the idea became a widespread belief, there would be even more people taking up sports like sky-diving or drag-racing than there are at present.