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Fascinating conversation...
Is the universe full of advanced alien civilizations? If it is, why don't we have overwhelming evidence of their existence? The Doomsday Argument is a mathematical theory that aims to cast light on these questions.

Suppose that you are staying in a hotel, and you know that either
(a) the hotel contains 10 rooms, consecutively numbered 1 to 10, or
(b) the hotel contains a million rooms, consecutively numbered 1 to 1000000.
Suppose that in addition, you observe that you are in room number 7. Given this, which of possibilities (a) and (b) is more likely? If (a) is true, you have a 1 in 10 chance of being in room number 7. But if (b) is true, you have a 1 in a million chance of being in room 7. So it seems that (a) is much more likely.

The original Doomsday Argument works like this, but with civilizations. Let's say that you are the 70 billionth person ever to have been born. Given this, what is more likely: that the number of people who will ever live is a few hundred billion, or that the number of people who will ever live is much bigger than this? Following the hotel room logic, it would seem reasonable to deduce that there will never be trillions of human beings.

However, this argument is incorrect, because it does not take into account the fact that you are much more likely to exist in a large civilization than in a small one. To correct for this, one needs to regard people as randomly picked from the set of all possible people. In his 2012 preprint The Doomsday Argument in Many Worlds http://arxiv.org/abs/1209.6251 Austin Gerig goes further and regards people as randomly picked from the set of all possible people in all possible parallel universes, in which the copies of the "same" individual in the various universes are all identified as a single person. This new version of the argument fixes the aforementioned problem in the original argument.

Gerig asks some interesting questions about this scenario. Given that you are the 70 billionth person to be born, and that you do exist, which is more likely? Are there many advanced civilizations in the universe, or just one? And is it the case that civilizations tend to become extinct before producing trillions of individuals or not? The probabilities in the picture are calculated on page 11 of the paper; I am calling civilizations doomed if they typically become extinct before producing trillions of individuals. The conclusions are very striking: it is overwhelmingly likely that there are many advanced civilizations in the universe, but also overwhelmingly likely that each one dies out before producing trillions of individuals. In particular, the model in the paper predicts that our civilization will die out within a few centuries.

If this sounds too depressing, you may enjoy the recent article 5 Insane Theories About Why We Haven't Discovered Alien Life by Fernando Ramirez; it may be found at http://www.cracked.com/article_20216_5-insane-theories-about-why-we-havent-discovered-alien-life.html

In summary, the five insane theories are:

5. If They Exist, They're Likely Too, Well, Alien
4. They Might Not Want to Screw Us Up
3. We Might Not Be Worth the Aliens' Time
2. We'd All Be Dead by the Time It Happens
1. Aliens May Not Exist at All

Ramirez cites Gerig's paper as justification for reason number 2. The article (seen via ) is entertaining, if speculative, and is worth reading

#mathematics #sciencesunday
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On Violence & Liberty...

We cannot and should not "let it go" or "give it a rest"...we have to, we must, at the very least keep talking about. If we do, at some point our words will be made manifest through our deeds. We will be held accountable to our commitments and intent; the world will change and we will be the architects of that change. We can redeem ourselves from the blight of violence through unwillingness to accept its inevitability; through our intransigent, unshakeable desire to make straight what we our inattention has made perverse and crooked.

More football, more entertainment, more diversions wo'nt heal us. Simply hugging YOUR children won't make them more safe, it wont make us WHOLE - they and us are still in danger from our collective unwillingness to take meaningful action.

No, what changes things is a courageous about-face turn toward what ails us, confronting our pathologies and leaning INTO our problem. We must be tireless, stubborn and relentless. Most importantly we must never forget what is at stake and that we simply cannot afford to continue pay this unreasonably high price of privilege and "liberty" any longer. We can fix this, failing that or until we do, we must ceaseless continue to try...

I just don't understand the resistance - guns have a singular destructive purpose regardless of their application. They were conceived, put into service and have proliferated (in the US) at a remarkable rate - all due to their unique characteristic of being able to end life with detachment, efficiency and unmatched efficacy.

Why would any reasonable, life-affirming, human being be compelled to advocate for their continued social acceptance, or civilian/"commercial" usage for any other reason than (reasonable?) paranoia, a pathological sense of insecurity; and maybe, no small measure of machismo/bravado?!?

Moreover, the continued unchecked proliferation of firearms has enabled the "merely" disturbed, amplified their pathologies turning their inner angst loose and manifesting it on our communities at an exponentially more destructive and homicidal level. This confluence of factors and dire consequences necessitates our attentions.

But these challenges continue to go unaddressed in any meaningful national dialogue, especially in light of tighter and tighter budgetary/spending constraints. But where we refuse to spend either monetarily or emotionally, we continue to PAY in lives and security.

We can and should have a conversation about mental healthcare and a reasonable discussion about the epidemic of gun violence. And, If we are perceptive, we will begin to understand that they are profoundly and intimately interconnected public health concerns and not just politically compelling talking points or wedge issues.

Our liberty is indeed in danger - from within, and from itself. If our national public health epidemics go unresolved we will be held captive by our fear and anxiety. At worst our amnesia will set in and we will become complacent and consequently be at greater risk. If do not reconcile our paranoia and examine how it informs and enables our 2nd Amendment "freedoms;" if we do not dress-down our denial of the impact that this "right" has had on our culture we will loose far more than our guns, something far more valuable - we'll lose our humanity.

#twocentsgiven #notoveryet