Doomsday argument

[polymath]

http://en.wikipedia.org/wiki/Doomsday_argument

http://www.anthropic-principle.com/preprints/cau/paradoxes.html

The 'Doomsday argument' basically says that if we suppose mankind will avoid extinction for a long time (like say, 5 million years), then it is a remarkable coincidence that we personally happen to live in as early era of humanity as we are now. Therefore it seems to be a lot more probable that humans will be extinct sooner than later.

I personally think that the logical fallacy in the argument is that it isn't really possible to exactly define what counts as 'human'. If we go back in time, there is no well-defined point in time before which we were some less developed primate species instead of being humans. Similarly, when we develop in the future through evolution (and probably genetic engineering), there will be no well-defined point after which we have turned into some more developed species.

Does anyone have more comments about DA?

 

[rangrz]

You know, the most amazing thing happened to me tonight. I was coming here, on the way to the lecture, and I came in through the parking lot. And you won't believe what happened. I saw a car with the license plate ARW 357. Can you imagine? Of all the millions of license plates in the state, what was the chance I would see that particular one tonight? Amazing!

http://www.askamathematician.com/2009/12/q-why-do-weird-things-happen-so-much/

Which answers the issue "Why am I alive at this point in the temporal range of the human species?"

 

[P A]

I suspect that this is a case of over-enthusiasm, wild extrapolation from available data, and linguistic/mathematical conflation giving rise to a thought-provoking pseudo-problem.

The 'Doomsday Argument' sidesteps such important (but, alas, highly informal) philosophical/scientific issues as temporally consistent nomenclature (as mentioned above, what counts as 'human?'; what doesn't?), conventional notions of causality, and egregious overdetermination. I think of this as being more akin to a clever puzzle, or even a paradox of sorts, but not an argument offering a tentative statement of fact. The theory itself appears to be internally consistent, and is capable of being intuitively grasped with relative ease - but that doesn't make it sound nor rigorous enough to warrant 'serious' discussion, and quite a few other, better theories about the universe have been thoroughly discredited in the past. In other words, think Zeno's paradoxes; not Apocalypse Now.

Also, I'm not sure if it's fully relevant here, given this theory's (supposedly) solid basis in probability theory, but cf. David Hume's critique of induction.

 

[polymath]

Dawn of Man: http://www.youtube.com/watch?v=xd3-1tcOthg

Did the prehistoric ape become the first 'human' on earth when it learned how to use a weapon, having been 'just an animal' before that?