... It is not about ... life meaning, but about probability. I was asking why an immortal person today would happen to be in an extremely low probability time window of existence.
I am not sure if this is what you are asking for, but maybe you mean the human life expectancy. It is the average time a human is expected to live.
As general the life expectancy is increasing with the time, and is different for each country.
https://en.wikipedia...n_1950-2050.png
Now lets imagine, that you are born in the period of 1970-1975 of that graphic and we will be watching the average line (the blue one). In this case, you are expected to live to your 59 years. But things develope, such as medical sciences become better, and people start to live longer as general, and in 1980 you are now expected to live to your 61 years. E.g. for 5 years of time period you have gain the chance of living 2 years more. Now we are 2016 and you are now expected to reach your 70th birthday. E.g., the longer you live, the longer you are being expected to live, thanks to the achievements of the human brain. That are the good news. The bad news are, that this time for your life gain is too slow for you in order to be immortal. from 1975 to 2016 your life expectancy has grown from 59 to 70, e.g. for 41 years it has gain you 70-59=11 years more time.
In order to be immortal, you need to gain 1 year of life expectancy for 1 astronomical year. And this is the minimum for you to be immortal. This is why you have "low probability time window"