Speed and Likelihood

So I'm reading Carl Sagan's posthumous The Varieties of Scientific Experience, and overall it's pretty good. But Sagan does say something about the likelihood of the origin of life that I found nonsensical. He's talking about the origin of life on Earth and how it happened within a span of 500 million years, from the time conditions were probably suitable for the origin of life to the first actual evidence we have for life appearing. And then he says:

It must have happened very quickly. A process that happens quickly is a process that in some sense is likely. The faster it happens, the more likely it is.

Wha-huh?

He then gives lip service to the problem of extrapolating from a single instance of an event, but that's entirely the point. We have very poor understanding of how life originated, so we can't say how likely it was. And the speed with which a process happens does not correlate with the likelihood of that event happening. If somebody does have evidence or an argument to the contrary, I'd like to hear it.

Think of it this way: Let's say you roll 100 dice, and you want to know how likely it is that all of them turn up as sixes. Now, you're not measuring the likelihood of it recurring, just happening once. This could happen on the very first roll, or it could happen after 40 million rolls. Do either of those situations (it happening quickly vs. after a very long time) convey any particular information about the likelihood of the event?

Waiting for Gustav

According to projected paths, Hurricane Gustav is supposedly headed on a direct course for Lafayette, where I happen to live. Of course, there are a million variables. It could hit anywhere from Houston to Florida instead. It could lose steam (although at this point they're saying it's more likely to pick up power).


I'm not planning on leaving yet. I'll make a decision tomorrow morning. Hopefully by that time we'll know a lot more, and hopefully it won't be bad.

Photorealistic Human Modeling is Here

The way the rendering of humans in movies and video games was going, you wouldn't think it would be long until they were pretty much indistinguishable from real people. Well, it looks like we're there.

Check out this story and the accompanying video.

Why The Drinking Age Should Be 18

Slate has a new article denouncing the current efforts by a coalition of university Presidents to curb binge drinking by lobbying for the national legal age for consuming alcohol to 18.

The article argues that lowering the drinking age won't be effective, and will actually do more harm and cost more lives, pointing to evidence from other countries who lowered their drinking ages. I wouldn't expect anything other than a spike in drinking once a given demographic gets new legal access. Long-term statistics are more meaningful, but we don't get those.

But even if the higher drinking age saved more lives and led to more binging and not less, there's a very simple, powerful reason why it's stupid and should be changed: It's not consistent and it's not just.

In every other facet of life, our country designates 18 as the age when a citizen becomes an adult. When you reach 18 you can buy porn and cigarettes. You can marry. You can vote. And if you are male, you are required by law to register with the Selective Service, which means you're put into the draft pool for war. There is a fundamental absurdity with saying that someone is old enough to operate a multi-million dollar piece of military hardware, kill others for their country, and die for their country, but is not mature enough to buy and drink a can of beer.

So the drinking age needs to be lowered to 18. Either that, or we need to unilaterally recognize a higher age (like 21) as the threshold for adulthood. The mismatch just doesn't make any sense.

What is Hiearchy?

In my primate cognition class last semester, we were having a discussion about baboon social structure, I think, and we were talking about it being hierarchical. The professor asked me what "hierarchical" meant. I was taken aback for a few moments, and couldn't come up with a response. It's good to question the meaning of words you tend to take for granted.

After reading On Intelligence in 2005, Hawkins convinced me that time and hierarchy are crucial to understanding cognition. Whether his company's particular implementation is the right technological path is an open question, but I think in terms of identifying the important theoretical concepts, he's dead on.

So what is a hierarchy?

In The Sciences of the Artificial, Herbert Simon says:

By a hierarchical system, or hierarchy, I mean a system that is composed of interrelated subsystems, each of the latter being, in turn, hierarchic in structure until we reach some lowest level of elementary subsystem. (emphasis mine)

I didn't find this definition very satisfying, though it's all right.

Wikipedia does a nice job, I think:

A hierarchy is an arrangement of objects, people, elements, values, grades, orders, classes, etc., in a ranked or graduated series.

...

Items in a hierarchy are typically thought of as being "above," "below," or "at the same level as" one another.

Not bad, though I'd truncate it down to simply:

A system of ranked elements.

Rank, it seems to me, is the most important aspect of hierarchy, and this simple working definition seems to capture nicely the essentials of hierarchy.

So why is hierarchy important to understanding cognition?

Well for starters, because the world is hierarchical. The universe is composed of galaxies, which are composed of subsystems, including solar systems. All matter is composed of atoms and molecules, which are composed of subatomic particles. And multicellular organisms, including ourselves, are composed of subsystems (nervous, circulatory, etc.) that are composed of organs composed of cells composed of molecules and so on.

And that's just spatially. Temporally, our lives are composed of stages (early childhood, adolescence, the college years, etc.), which are hierarchically divided down to individual moments.

Our neocortex is hierarchically-arranged, and I believe its architecture has evolved specifically to exploit and encode the hierarchical nature of the world around us. In The Quest for Consciousness, Christof Koch refers to the neocortex as "quasi-hierarchical," by which he means that it is not a strict hierarchy. Some cortical areas don't report directly to the area just above them. Many connections skip levels, like a private reporting not only to his sargeant, but to the general as well.

I don't really like the term "quasi-hierarchy" much, though. The neocortex is no less hierarchical because of this arrangement. If a system is composed of elements which are all the same rank, it's not a hierarchy. If there is any difference in the ranking of elements in a system, then it's a hierarchy. I'd prefer qualifiers like "strict" and "flexible" to describe the extent to which the relationship between elements in a hierarchy is between adjacent levels.

And I'll leave you to ponder this adapted diagram of the organization of the macaque monkey's visual from Felleman and Van Essen (1991). The information flows from bottom to top. The bottom part is information coming from the eyes, and the hippocampus sits on top. Our visual processing system is very probably arranged in the same way.

The Lockhart Post-Register Has a Website?

I grew up in Lockhart, Texas. We had a newspaper, which I imagine is a lot like most small-town newspapers. It was delivered once a week, consisted of about 10 small news sheet pages, and thrilled readers with stories about intersection lights in Lockhart going out and the goings on of the local Chamber of Commerce.

I was Googling around today and came across the Post-Register's website, and holy shit, the thing looks professional! That top banner is a monstrosity, but even it is well-designed, graphically-speaking. This site looks about 100 times better than the newspaper ever did. I'm impressed.

And the copyright notice at the bottom says 1999-2008, so they've been up and running for 9 years and nobody told me.

So now you can read thrilling small-town news in vivid color on a well-designed website. As I write this, the lead story is about the "controversial" decision to rename Lockhart High School.

Go check it out!

Obama on Faith

When I wrote my review of Barack Obama's The Audacity of Hope, I hadn't yet gotten to the chapter on faith. Well, now I have read it, and I'm not particularly impressed.

Obama apparently grew up in a secular household, but converted to Christianity in his mid-20s. His reasons for adopting Christianity are patently utilitarian. He talks about the effectiveness of black churches in organizing blacks, improving neighborhoods, effecting social change, and instilling morals in the community. He talks about how his mother died after a long fight with cancer and how he saw fear in her eyes, and wished that she had religion to comfort her. And he talks about when his own young daughter asked him about death for the first time, and he told her something like "You don't have to worry about that for a long time." This skirted the question, but he says in his book that he hopes that his mother has gone to a better place where she can be with people she can talk to and love for all eternity.


Okay. But your desire to believe something that makes you happy certainly doesn't make it true. Obama also talks about how religious people shouldn't leave reason at the door, but as far as I can tell, he doesn't give a single justification for his beliefs based on reason.

I've talked here many times about the fallacy of utilitarianism. You could believe all sorts of things that are false that could make you happier and more productive. In the end what matters is your values. If you really do value truth more than happiness, then you'd never accept a pleasant fantasy over cold, hard reality. But if you value happiness more than truth, you'd certainly be willing to buy whatever someone's selling as long as it made you that much happier.

Obama at least speaks inclusively about non-believers, and he talks about the dangers of using the state to inflict religious beliefs on others. This is better than most candidates, I suppose, but I just wish he would apply the same level of scrutiny to what he says he believes about religion that he does to Republican policies.