Doomsday-Argument

The Doomsday argument, German doomsday argument is a mathematical consideration, which claims to be able to make a probability statement about the timing of the end of mankind on the basis of only an estimate of the total number of humans born so far.

It was first proposed by the astrophysicist Brandon Carter in the 1980s and subsequently represented by the philosopher John Leslie. It was alleged independent of God by Richard III and HB Nielsen. Similar theories that derive an end to the world by population statistics have been previously proposed already by Heinz von Foerster and others.

Formulation of the argument by Richard Gott

Let's take our position f = n / N on the chronological list of all people who will ever born, with n as the absolute position from the beginning of the list, and N as the total number of people.

Suppose that we have ( with the other N people ) find us with equal probability at any position n, we can conclude that our position f of a discrete uniform distribution on the interval (0; follows 1 ] before we learn our absolute position.

Suppose, moreover, that our position f on (0, is uniformly distributed 1], even if we experience our absolute position n.

We can now say with a 95% probability that f = n / N in the interval ( 0.05, 1] is In other words: We are 95% confidence that we have in the last 95 % of all people. are ever to be born.

Where n our absolute position, which implies an upper bound for N, by rearrangement of

To

If we assume that by now 60 billion people were born ( Leslie assumption), then we can say probability that the total number N of all people who will ever be born, below 20.60 = 1200 ( billion ) amounted to 95%.

From the assumptions that the world population stabilizes at 10 billion at the same time living people and a life expectancy of 80 years is reached, you can then calculate how long it will take until the remaining 1.14 trillion people have been born: survived with 95 % probability humanity no more than another 9120 years. Depending on the assumed future population trends vary the result.

Criticism

The validity of the Doomsday argument is highly controversial. Superficially, it seems to be a simple calculation the Doomsday argument, a mathematical calculation. Here, however, overlook the fact that the bill is a philosophical assumption, the so-called self -sampling assumption ( German as " self - sampling assumption " ), underlying that is highly controversial. Since this is a philosophical assumption that they will, like the whole Doomsday argument, not among mathematicians, but among philosophers discussed controversially.

The assumption of self -sampling can be formulated as follows:

" Observers shoulderstand reason as if theywere a random sample from the set of all observers in Their reference class. "

" Observer should conclude as if they were a random sample from their reference class. "

All people If we take the class of all people who have ever lived (as in the example calculation above in the article), or at least the class of all living beings, all scientists: Even if we assume this assumption to be valid, still the question of the reference class remains open born in 2000 or later, etc. Depending on which class one assumes, the calculated probabilities change considerably.

Can be neither proved nor disproved assumption The statement of self -sampling by their nature. Of critical researchers but many thought experiments in which the application of the self -sampling assumption were constructed leads to intuitively implausible results.

Further comments:

• A precise formulation of the argument requires a Bayesian interpretation of probability.

• The argument assumes no prior knowledge about the distribution of N. This is a reasonable assumption for a principled argument.

• The argument makes an implicit assumption that N is limited. Leaving physical arguments such as aside the heat death of the universe, it could, in principle, an infinite number of people. It is not clear how the argument would apply in this case.

• Even the correctness of the argument would not necessarily mean that the human race will die out after 1.14 trillion people lived. There are other ways of interpretation, for example, that humanity continued to evolve through evolution (or deliberate self-development ) in posthuman beings.