Advanced Civilizations in Decline - part 1

If something can't go on forever, it won't.  Simple, right?  And yet, the notion that things will always continue to trend as they are is a common fallacy, and leads to real estate bubbles and the collapse of monetary systems.

Moore's Law

In our times, we tend to think of technological progress as something that only accelerates forward.  First we master materials, then energy (thanks to our improved materials), then information (thanks to cheap, abundant, widely distributed energy), and then, possibly something beyond information. We now casually toss around references to Moore's Law, which isn't a law at all, but simply an observation of how our technology continues to improve by some fairly simple metrics: the number of transistors on a chip, the cost of a gigabyte of data storage, and so on. We expect these trends to continue until we have reached a point beyond which no prediction is even theoretically possible.

However, this is a relatively recent trend, and we forget how many ancient civilizations had sophisticated capabilities that have been lost to us, or that we have had to recreate from scratch. They rose, they fell, they lost the recipe. Historians continue to analyze why the great civilizations declined, but once large, complex internal structures form, they begin to differentiate into interest groups that no longer have it as their principal goal to perform their greater function, but rather to maintain or grow their share of the resources flowing through the machinery. When a system fails this way, we call this "collapsing under its own weight."

What Skepticism Isn't

A woman came up to me and said,
"I'd like to poison your mind,
With wrong ideas that appeal to you,
Though I am not unkind."
  - - - They Might Be Giants, "Whistling in the Dark"

I have recently written a post advocating what I would call skepticism.  In my view, skepticism comprises some fairly basic value judgments, some fundamental skills, and a process or approach to all testable claims.  Skepticism is a necessary component for navigating the minefield of delusion, deception and cognitive dissonance we all must pass through, whether we are scientists or not.  A necessary component yes, but we are learning the hard way it is not sufficient - we also need a set of emotional tools to stay calm, be kind, and to keep from getting lost.  I would like to address how we recognize skepticism and tell it apart from its imitators.

Searching for Bracewell Probes - part 1

Ronald Bracewell

Bracewell Probes were first discussed by Ronald Bracewell in a 1960 Nature paper. The basic idea is send robotic probes to solar systems that seemed promising, and these probes would sit and wait for millenia looking for signs of intelligent life in those systems, and should those intelligent creatures ever reach a certain measure of sophistication, then either radio home for instructions, or simply provide a library of advanced knowledge that would help these lowly beings achieve a kind of galactic citizenship.
that the "Superior Communities" would

Bracewell Probes still seem like a sensible way for superior communities to reach out in their galactic neighborhoods, whether their intentions are benign or defensive. Rather than guessing when to send probes to check out a suspect solar system, they simply strike out for all of them in the neighborhood, and then wait. Would their purpose be, as Bracewell conjectured, to enlighten us, or simply to alert the rest of the superior community that here there be uppity apes?

Speculation - the only way to fly

Ronald Bracewell

Here is another speculation, but probably not very original. In fact, it's a variation on the 1960 concept of a Bracewell Probe.  It's hard for me to imagine that some science fiction author or another hasn't treated this in some form.

In the future, we expect to be able solve these three broad classes of technological problem we haven't got a a handle on yet:

1. Very large sensors that can remotely sense distant planets accurately enough to ascertain their habitability with a high confidence.
2. The hosting of a human mind on a machine substrate - i.e. a truly intelligent machine.  This implies that the state of a human mind could be captured - "uploaded" onto a machine and captured in a data set. In other words, we could completely define what we now call the "self" in terms of data.  The crucial thing here (within an order of magnitude or so), is how much data.  Let's say it's about an exabit compressed, or  10^18 bits.  Some estimates are lower that, but I think we need lots of margin.  
3. Travel across interstellar distance, although the problems of doing so quickly ( a significant fraction of the speed of light and exploiting time dilation effects) may prove to be insurmountable no matter how sophisticated our technology is, and at present we have only the broadest concept of how to cheat the speed of light limit.

Let's assume we could do both 1 and 2, but item 3 could only be done slowly, so that it takes hundreds or even many thousands of years to travel between the stars.  This would be a hopelessly tedious journey for a human or superhuman intelligence, and all the mass required for reliable life support would only slow it down and limit options for deacceleration.

So, we would want to send only a small mass to another star system and it would take a long time and cost a lot of energy.   However, we can transmit information far more cheaply and at the speed of light.  You might need a really big and powerful transmitting array, but this is just scaling up from current technology.  To transmit an exabit in a year you would need a transmission rate of about 30 gigabits per second -  well within plausibility, even over interstellar distances.  The size of the receiving antenna you would need on the other side would increase with the distance (roughly 100 meters on a side at 100 light years, given plausible assumptions about  the transmitter, noise temperature and losses), but such antennas can be made from gossamer materials that can be folded compactly.

Stories, Conjectures, Evidence and Proof

OK, we need to clear a few things up here.  People throw around words like "evidence" or "proof" a mite too loosely for my liking.  In an earlier post, I talked about evidence for the "hypothesis" (yes, scare quotes) that some UFO sightings are alien spacecraft, and why it's not so straightforward to say that.  And yet, almost everyday we hear claims of proof or evidence both for and against.  Let's talk a bit about what that means.

 

Short Version

 Evidence isn't just evidence - it is evidence for or against something.  Before that, it's just data, or worse, stories.  In order for data to serve as evidence we need to be able to fullfill three conditions:

1. We need a decent idea of what that something is and how we expect it to behave, i.e. a Hypothesis.
2. We need at least an approximate idea of how the data we have or propose to gather could be produced if the hypothesis was true (and, if it false).
3. We need to bend over backwards to honestly ask and answer the question: what if I'm wrong?  You can be wrong about the hypothesis, or you can be wrong about the evidence, and data can be just noisy or biased.

When you have all these things in place, and the odds that the data we have if your hypothesis is true are greater than the odds of the same data if the hypothesis is false, then you can claim that there is evidence for your hypothesis.  Not proof - proof means that your hypothesis is logically unavoidable, which is a much stronger (and almost certainly wrong) claim.

This leads us to problem we get with stories as evidence.  Also, with such conjectures as ghosts, alien spaceships, or cryptids  - we can't fulfill the first two conditions listed above, so are lost in claiming that some data we have is evidence for that.