- #1

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Every day I wake up, I can say:"Today, at the end of the day, I have a probability of 0.5 to be live( or to be dead)!".

Now, one can calculate the probability that after some numbers of day I am death:

is equal to: 0.5 (prob. 1st day death) + 0.5(1st.live)*0.5(2nd death) + .... and so on , and it tends to 1.

For example after 2 days: P = 0,75 to be death.

If I calculate the probability to death exactly the 2nd day is: P = 0.5*0.5 = 25%, and it decrease with day number.

And the probability to be live at the "end of the n-day is" : (0.5)^n.

Now there is my question:

If I wake up the second day, I can say:"Today I have a probability to live of 0.25 ( 0.5 1st day * 0.5 2nd day) "

But If I cannot say when I start to have "a life on probability" I can say:"Today I have 0.5 of probability to live!".

But this is wrong, because probability cannot change from different observer, so what I can say?

Thank you