All of us have heard that life contains 2 inevitable occurrences: annual taxes and death. My first encounter with taxes came several years ago when I started working; my first encounter with the idea of death occurred when my maternal grandfather was sadly taken away on a stretcher on a sunny morning during the summer of 1994, when I had just eaten some pancakes at my grandparents house, at the age of 5. I was not really sad when I found out about death, as I did not really comprehend it, nor did I believe it would happen to me. It took years before the depressing thought that I do not last forever.
Let's talk about death. We all know that anybody who has ever walked on this planet has a maximum of about 120 years before they become a part of history. This seems to make great sense, as every president before Nixon has long since passed away, no veterans remain from the Civil War, living members from our family tree can only be found within the last 100 years or so, and logically, it makes sense that there are so many things that could end a life, yet there are very few that could preserve it.
What if all of that was false?
You might wonder how that could even be possible. With the immaculate quality of today's record keeping, the world would be strongly publicizing anybody who manages to live 150+ years, and the probability of surviving diseases and medical conditions to which the elder are susceptible is beyond slim, and of course, there ought to be many more supercentenarians than we see around us, so what gives?
The answer requires knowledge of the structure of the multiverse (or the model of many parallel universes). An episode of family guy depicts Brian and Chris traveling through several different parallel universes. A notable example is where they travel to one in which dogs are legally obligated to walk humans on leashes. You might wonder as to how many parallel universes there are around us. The answer is basically... infinite.
Every time you make a decision, your world plays out to follow through with that decision, but other worlds simultaneously play out in which you decided otherwise; you simply don't experience them. When you were conceived, and your gender was chosen, another world simultaneously ran (and continues to run) to play out your alternative gender. Other universes are also created, in combination of alternatives for others and yourself. For example, if we consider two twins, we have 4 possible combinations of universes. If we expand the scope to include all the babies conceived on the same day, we have an extremely large number of universes created. We only experience one.
What this means is that when something tragic happens, such as the death of a loved one, another universe simultaneously plays out in which that person does not die. When it's your turn for a major illness, car accident, failed parachute... in theory, your consciousness will lead you into the universes in which you survive.
This is the idea proposed by both Hans Moravec (1987) and Bruno Marchal (1988), who coincidentally, independently, constructed the idea of "quantum suicide." If you fight in a heavy battle in war, you will simultaneously survive and get killed at the same time, so somebody will be reading the sad story of your demise, but fear not, you will only experience victory!
According to the theory of many universes, you will always be led into paths that lead to life, and will become the oldest person in the universe, but we all end up conscious in different universes...
All right, so it sounds too good to be true, and it probably is. What if the engine in your flight fails, or you are trapped underwater through some extreme misfortune? At what point are you led away from the universe? It seems like it would be too late in these situations to have any probability for survival. Is there some sort of manipulation to ensure that you are led out of these situations in the first place? It seems that it would be too manipulated of a universe for you to always escape the clutches of the grim reaper.
I would not put my money on the idea of living forever, but if I did, I wouldn't lose it until my tragic demise.
In short, don't make dumb decisions and assume that this idea will work out. I don't want to be cited as an inspiration for unsafe behavior.