Science & Nature Archive

Friday, January 29, 2010

'Scientific' Facts

MicroscopeSometimes, a term that you've heard your whole life suddenly seems strange, That's how it is for me and 'scientific facts'. When you think about it, that phrase seems a bit redundant. If something is true, it's a fact. It's that simple. It doesn't matter how you came to know it. If a statement lines up with objective reality, it's a fact.

What does it add to describe a fact as 'scientific'? I guess the first thing is to understand is what's meant by science. Generally, there are two related meanings to the word. The first is that it's a method. We should all know this method from grade school - come up with an explanation, gather evidence to test the explanation, refine your explanation, and repeat. The second is the body of knowledge we've learned through that method. But the thing is, everything that has an objective answer can be examined through science.

Consider an example. Some would consider the Earth orbiting the sun a 'scientific' fact. We as humanity may have learned about it through science, and we as individuals may have learned it in science class, but it doesn't change the fact that it's true. It's not as if the Sun used to orbit the Earth until Galileo came along. Can't we just call it a plain old fact?

There are a couple reasons I bring this up. One is for the people who like to point out that science can't tell us anything with absolute certainty, and therefore science doesn't deal in facts (like this exchange I had). When you consider things like solipsism and Last Thursdayism, you have to grant that for fact to have any meaning, it must mean very high level of certainty, and not 100% absolute certainty. Going by that definition, science certainly does deal in facts.

The other is for the people who think of science as something separate, as not really describing things as part of their world. To them, it may be a 'scientific' fact that evolution occurs, but but in their world, science is wrong, so describing evolution as 'scientific' means it may not have actually occurred.

Oh well, I'm not be expressing myself as clearly as I'd like, but it's late on a Friday, and I'm about ready for some supper and a beer. I guess the main point I'm trying to get across is something I already said in the first paragraph. Calling something a 'scientific' fact is redundant. Statements are either true or not, and if they're true, then they're facts. Since we can study everything with an objective answer through science, it really doesn't add anything to describe any facts as scientific. If they're not scientific, they're not really facts to begin with.


Added 2010-02-01 I thought about this a bit over the weekend, and realized that that last sentence might come off as a bit smug. So, I thought that maybe I should list a couple examples.

As the first example, consider the claim that Hawaii is the 50th state of the U.S. To look at this scientifically, we need to gather evidence to support that claim. We could start off by looking at current legal documents, which show that Hawaii is definitely a state. We could move on to archived documents, and find the Hawaii Admission Act, which shows when Hawaii became a state. We could move on to find documents of when each of the previous 49 states became states. We could study newspaper articles from each of those periods for additional confirmation. After studying all that evidence, then we could say that it is a 'scientific' fact that Hawaii is the 50th state of the U.S.

Next, let's move on to something that some would think was a bit more subjective. Consider the claim that I love my wife and daughter. To test this, people could observe my behavior around my family, and the actions I commit in relation to my wife and daughter. They could study my involuntary facial expressions, to see how I react around them. They could observe my behavior when they're not around, looking for signs of loneliness, or observing how I talk about them. So, even the claim that I love my wife and daughter can be considered to be a 'scientific' fact, since we can use the scientific method to investigate it.

That's what I mean when I say that all facts worth talking about are scientific. Sometimes, we only practice rudimentary forms of the scientific method to determine their veracity, but, at least in principle, the scientific method can be applied to them.

Thursday, November 5, 2009

Ray Comfort - Still Ignorant on Evolution

On the Origin of Species - The Ray Comfort EditionWow. Just, wow. I know I've talked about Ray Comfort more times on this blog than is healthy (for example - here, here, here, here, here, and here), but now, not just is he publishing his drivel on his own, making scam websites, or getting followers to put the equivalent of junk mail into books at the book store. Now, he's been published in a blog on the U.S. News and World Report website, and boy is it ignorant.

The background of this article is this. Ray Comfort is publishing two versions of a reprint of Darwin's Origin of Species, along with an introduction in each version. The first version was abridged, and the introduction was made publicly available on the web. After the negative publicity it received, Comfort made his second version unabridged, and supposedly with a modified introduction. To give an idea of the introduction, here's how Comfort himself described it (be forewarned - there are many falsehoods and examples of bad logic in just these two paragraphs*).

This introduction gives the history of evolution, a timeline of Darwin's life, Hitler's undeniable connections to the theory, Darwin's racism, his disdain for women, and his thoughts on the existence of God. It lists the theory's many hoaxes, exposes the unscientific belief that nothing created everything, points to the incredible structure of DNA, and the absence of any species-to-species transitional forms.

It presents a balanced view of Creationism with information on scientists who believed that God created the universe—scientists such as Albert Einstein, Isaac Newton, Nicholas Copernicus, Francis Bacon, Michael Faraday, Louis Pasteur and Johannes Kepler. It uses many original graphics and "is for use in schools, colleges, and prestigious learning institutions." The introduction also contains the entire contents of the popular booklet, "Why Christianity?"

Towards the end of September, Dan Gilgoff posted an entry in his God & Country blog on U.S. News & World Report describing Comfort's book (the first version). After all the feedback Gilgoff got for that entry, he decided to revisit the issue. He set up an online debate between Ray Comfort and Eugenie Scott, the executive director of the National Center for Science Education. The debate consisted of four posts in total - Comfort's original argument, Scott's original argument, Comfort's response to Scott, and finally, Scott's response to Comfort.

I guess there are several ways I could have addressed this in a blog post, but I've decided to focus on Comfort's second post. That one struck me as so out and out ignorant, that it seemed a ripe target. I encourage you to read Scott's response first, but I thought I could supplement what she already wrote.

Continue reading "Ray Comfort - Still Ignorant on Evolution" »

Wednesday, September 23, 2009

If Evolution Isn't Directed, Why Is Life Now More Complex Than in Ancient History?

A common misconception about evolution is that it has a goal, that organisms evolve from lower to higher forms. This is sometimes referred to as the Ladder or Progress, with primitive forms at the bottom and more advanced forms towards the top of the ladder (and commonly, being the self centered species that we are, with humans on the top rung). This isn't true. Evolution has no direction. Organisms adapt to fit their local environment in whatever way works best. But if evolution has no direction, why is it that life now is more complex* than life from billions of years ago?

This really is pretty easy to understand once you give it a little thought. Let's use distance as an analogy. There's an old saying, that the journey of a thousand miles begins with a single step. You can't walk from Los Angeles to New York instantly. It takes many, many small steps (literally in this example) to get there. If we consider Los Angeles to be simple, and New York to be complex, then at any point on your journey, as you've increased your distance from LA, you've increased your complexity. And it's obvious that you can't get to a certain point of complexity until you've already taken all the previous steps leading up to it. You can't just instantly go from simple to complex.

But a journey still implies direction, and I've said evolution doesn't work that way. Evolution is more like a drunkard's stagger. If you have a drunk that starts out in LA, and let him wander aimlessly with no particular destination in mind, he may eventually end up in New York, but it definitely wouldn't be a straight line. He may just as likely never make it to New York, and never even leave LA. To extend the analogy further, he may end up in Seattle. He'd still be a long way from LA, but in a completely different direction. Squids, for example, are remarkably complex, but they took a different path to their complexity than us vertebrates, and their resulting complexity is different from ours.

Below is a graph that roughly illustrates this in an evolutionary context. It starts off at zero, and for every step, it goes up or down by a random amount** between -0.5 and 0.5. After every 10 steps, it splits, and each new 'lineage' then varies in that same manner. This was carried on for 40 steps, resulting in 8 lineages by the end.

Random Distribution Simulating Evolution of Complexity

Remember, this is all random variation from a starting point at zero, going in small steps. After 40 steps, one lineage had varied to more than 3.4 away from zero, while other lineages didn't vary very much away from zero at all. If this was representing complexity, and if the steps were assumed to be thousands or millions of generations, it demonstrates how complexity can evolve slowly from simple beginnings, without any conscious aim toward increased complexity. (As I said, this is only a rough illustration of evolution. Evolution is driven by more than just random variation, and the divergence of lineages isn't as predictable as that.)

Evolution really does sometimes decrease complexity. For an intimate example, consider what you're sitting on - a nice smooth posterior. Some time millions of years ago, our ancestors lost their tails, a complex feature with muscles, bones, and tendons. Their lifestyles were probably such that a tail just didn't really do that much good, so there was no reason for natural selection to maintain it. And now, we have backsides that are less complex than our simian ancestors.


*'Complex' is actually a little hard to define. How exactly do we mean complex? Number of genes? Number of specialized cell types? How do we even differentiate specialized cell types? (more info) This seems like one of those problems where we know it when we see it. I think most people would agree that a mammal is more complex than an earthworm, even without a quantitative definition of that complexity.

**Technically, a pseudo random number generator was used (Visual Basic). For this application, that's close enough to truly random.

Wednesday, June 3, 2009

Bees

I had an interesting experience at work last Friday. Some time in the early afternoon, we started noticing some bees around the entrance to a trailer. We hadn't seen any yet this summer, so I poked around to see where they were coming from. I saw a few going in and out of a hole in the liner under the floor, so I ran home to get some wasp poison, and sprayed around the hole. As the afternoon wore on, more and more bees kept showing up. I kept spraying for a while, but eventually gave up. By the time I left to go home, here's what it looked like (I gave two different resolution options to view these bigger):

Bees View 1
800x600 (92.4 kB)
2816x2112 (504 kB)

Bees View 1
800x600 (104 kB)
2816x2112 (514 kB)

Bees View 1
800x600 (104 kB)
2816x2112 (491 kB)

And here are a couple videos of it that I uploaded to YouTube. The first one's a bit long, but you don't have to watch the whole thing. At the end of the second one, I got scared when I felt something land on my arm, but I didn't get stung.

By Sunday, the bees were no longer on the step, but had taken up residence under the trailer. We had to call in a bee keeper to get rid of them. He came in after dark on Sunday (so that the bees would be in the hive) and worked until midnight. He said that there must have been at least 20,000 bees. He didn't think they'd been there very long, that they'd probably just arrived.

That is, by far, the most bees I've ever seen in my life.

Friday, February 27, 2009

Investigating a Few Claims from Global Warming Doubters

Global WarmingThis past weekend, I got into a discussion with a couple friends about global warming. This was a different group than the one that inspired this blog entry, Global Warming - It's Real, And We're Causing It. These two had several arguments against global warming, not just a general distrust of the science. Like I wrote in that other entry, I'm far from being an expert in climate science. I've kept up with it a bit, but I've mostly trusted that the actual experts know what they're talking about, and when they said that there's a very, very high probability that global warming is human caused, I believed them. Well, arguments from authority don't carry much weight when people are giving you specific reasons why they doubt a theory. So, I had to do a little deeper research into their claims.

Below is the response I sent to them via e-mail. Since it's so long, I'm not going to put it in blockquotes. Also, since I'm posting this on my blog, I'm not going to use their real names. But rather than calling them John Doe I and John Doe II, I'll go with the first names from Comedy Central's news hour, John and Stephen.

[start of e-mail]

John & Stephen,

John, I know you're used to these e-mails. Stephen, this is just what I do after discussing something controversial - backing up what I said with a few references and doing a little more research. It looks like you do about the same - [my wife] gave me the articles you found.

Okay, first I guess I'll try to cover a few of the things we discussed over the weekend. There were a few points brought up that stuck out to me: 1) CO2 is not a greenhouse gas, 2) 30 years ago climatologists were predicting an ice age, while now they're predicting global warming, so how can we trust what they're saying, 3) Current data indicates that we're actually headed into a cooling period, 4) Mars ice caps are melting, indicating that increased solar activity is responsible for the recent warming trend, and 5) Sensors used to take measurements of polar ice were flawed, so we can't trust those measurements. I probably got a few of those wrong, mixed up a few with claims I've read on the Internet, and there are probably a few that I forgot, but that's mostly what I remember. So, I tried looking up those claims and here's what I came up with.

1) CO2 is not a greenhouse gas.

I guess you already looked this up, Stephen, since you wrote on the printouts you gave [my wife] that CO2 actually is a greenhouse gas. Just to give a little information for John, though, here's some more info, mostly summarized from Wikipedia (http://en.wikipedia.org/wiki/Greenhouse_effect). Most of the electromagnetic radiation the sun emits is in the visible spectrum. Greenhouse gases, pretty much by definition, don't absorb light in the visible spectrum, so most of the radiation from the sun makes it all the way to the surface of the Earth. There, it does get absorbed by numerous objects. As these heat up, they will radiate some of that energy back out in the infrared spectrum. Now, greenhouse gases, again pretty much by definition, do absorb light in that spectrum. So, the gases absorb that infrared radiation and heat up. Some of that heat will be transferred to surrounding gases, with some of it eventually making it back down to the ground. Some of it will be radiated back out in all directions - some back towards the ground, and some out into space. So, the net result of having greenhouse gases in an atmosphere is that the temperature of the planet will be higher.

The main greenhouse gas in our atmosphere is water. It provides around 36% of the heating. Next comes carbon dioxide, at around 9%. It's a little difficult to calculate how much heating each gas provides, since they interact with each other. For example, if you remove all the CO2 and water from the atmosphere, we would lose more than 45% of the greenhouse heating.

Here's another link, showing the actual absorption spectrum of CO2, and giving a more detailed explanation of how the absorption works on a molecular level:
http://www.wag.caltech.edu/home/jang/genchem/infrared.htm

There are other greenhouse gases, as well. Some are more effective on a pound for pound basis (such as methane). However, because their concentrations are so much lower, their total effect isn't as great.

One argument I have heard, is that carbon dioxide may be a result of warming - that some mechanism causes more CO2 to enter the atmosphere as the temperature increases. This argument is usually in response to the historical trend of global temperature vs. CO2. However, we can be pretty darn sure that much of the reason CO2 levels are rising right now is because of people burning fossil fuels. All that carbon was sequestered underground, and we're releasing it faster than it can be sequestered again. So, knowing that CO2 is definitely a greenhouse gas, if there's a mechanism that causes CO2 levels to rise with temperature, it's a feedback that's going to make the current situation worse.

2) 30 years ago climatologists were predicting an ice age, while now they're predicting global warming, so how can we trust what they're saying.

I wasn't paying much attention to climate science 30 years ago, so I can't speak to this directly. I do know that the way the media currently presents science is pretty bad. Look how much the media hyped the recent announcement of finding methane on Mars and how it could be indicative of life. The reality is that the current scientific consensus is much more conservative - it may be life, but there are many other possibilities it could be, and we just won't know until we get more data. So, if science reporting 30 years ago was anything like it is today, I could easily see the media playing up reports far more than what was the actual scientific consensus.

I found a fairly recent paper in the journal of the American Meteorological Society doing a literature search on climate research during the 60s and 70s. They found that a small minority of papers predicted global cooling, but that the majority actually were predicting global warming even then. So, it appears that the scientific consensus on global warming hasn't changed in the past 30 years, and has just gotten stronger. Here's a short blog entry describing the paper, which also has a link to the full paper:
http://www.realclimate.org/index.php/archives/2008/03/the-global-cooling-mole/

3) Current data indicates that we're actually headed into a cooling period.

For your reference, John, here's one of the articles Stephen printed out for me:
http://www.dailytech.com/Temperature+Monitors+Report+Widescale+Global+Cooling/article10866.htm

My main take of that article is that there's not enough information in it to predict that we've actually started a cooling trend. Average global temperature is influenced by quite a few factors, and thus fluctuates quite a bit from year to year. Global warming doesn't predict that every year will be warmer than the last, only that the trend is to higher temperatures. Just look closely at the graph they've provided. Several other periods show similar valleys, quickly rebounding to higher temperatures. Maybe this recent drop was the biggest, but not by a lot. Unless these temperatures stay low for a longer period than previous valleys, there's no reason to believe that this is a long term trend.

The only mechanism the article gives for why temperature might be decreasing is "reduced solar activity." Looking at the article linked to in the original article, the mechanism claimed seems to be the Sun's magnetosphere shielding Earth from cosmic rays, and the effect that has on cloud formation. The solar activity being described is not the solar irradiance. If solar irradiance were decreasing, I would fully expect that would decrease the Earth's temperature. How could it not? But actual measurements of solar irradiance show it to be pretty darn constant. It does vary slightly over an 11 year cycle (same as sun spots), but that variance is only ±0.65 W/m² about a 1366 W/m² average, or about 0.1% total variance.
http://en.wikipedia.org/wiki/Solar_variation

Hmm, I just found another record of solar irradiance in the NASA link a few paragraphs below. It looks like the current valley in solar irradiance is a little lower than the previous two valleys, but still not very far off from the average - maybe abut 0.15% total variation. It looks like we're right about at the minimum, and getting ready to start receiving more energy from the Sun again.

The links between other properties of the Sun and Earth's climate are more tenuous. I've seen a few studies claiming such links, but none that seem to hold up to scrutiny from other scientists. If either of you could send something showing a strong link, I'd be interested in reading it. That same Wikipedia article linked above discusses some of these proposed correlations:
http://en.wikipedia.org/wiki/Solar_variation#Global_warming

This article also addresses proposed correlations:
http://www.realclimate.org/index.php?p=180

As far as what could have caused the cooling, it looks like it my be due mainly to La Niña. NASA's Goddard Institute has a good discussion of this:
http://data.giss.nasa.gov/gistemp/2008/

I also found a report from June of last year that predicted this cooling. According to the link below, most climate models ignore short term effects such as El Niño and La Niña. For long term forecasts, they're not that important. For short term forecasts, however, they can have big impacts. The authors incorporated ocean currents into their model to give more short term predictions, and as I already said, they predicted the recent cooling.
http://www.ifm-geomar.de/index.php?id=4192&L=1

4) Mars ice caps are melting, indicating that increased solar radiation output is responsible for the recent warming trend.

The solar irradiance trends linked above show that the melting of Mars ice caps definitely isn't due to solar radiation, since solar irradiance hasn't changed by more than a fraction of a percent, and has actually been on the downward side of the cycle for the past few years. I'm not sure what other properties of the Sun would influence the ice caps on Mars.

A National Geographic news clip on this mentions that a Russian scientist, Habibullo Abdussamatov, thinks increased solar irradiance is heating both planets (again - see the actual measured solar irradiance in the Wikipedia link), but other scientists offer explanations for other factors that drive Mars' climate, including that the wobble of it's tilt axis is more pronounced than Earth's.
http://news.nationalgeographic.com/news/2007/02/070228-mars-warming.html

Wikipedia also has a section on this. The consensus seems to be that no one's exactly sure what's causing the Martian ice caps to melt, but it seems to be a local climate phenomenon, not a global one. With Mars' thin atmosphere and lack of oceans, it doesn't have the same thermal buffers as Earth, so smaller phenomena can have a larger effect. It mentions that dust storms could have darkened the ice caps, increasing the amount of solar energy they absorb, causing them to melt faster.
http://en.wikipedia.org/wiki/Climate_of_Mars#Evidence_for_recent_climatic_change

Here's another article discussing the southern Martian ice cap:
http://www.realclimate.org/index.php?p=192

I guess the short of it is, although people have hypotheses, no one's exactly sure what's causing Mars' ice caps to melt, because it's another planet that we haven't been able to study in enough detail to know the intricacies of what drives its climate. Although the solar irradiance argument put forth by Abdussamatov is almost certainly wrong.

5) Sensors used to take measurements of polar ice were flawed, so we can't trust those measurements.

To be honest, I'm not sure exactly which measurements you were talking about. I did see a mention of something in a recent entry on Carl Zimmer's blog (he happens to be one of my favorite science writers). Was this what you were referring to?
http://blogs.discovermagazine.com/loom/2009/02/22/a-wrinkle-in-ice-or-not/



I still don't know as much about global warming as I do about other fields, but the more research I do, the more confidence I have in the science. But, I could still be wrong. Keep sending me articles you think show global warming to be wrong. If it is, I'll change my view eventually. If the scientists are right, though, then the next thing to discuss is what to do about it. Do we even try to reduce our carbon output, or do we just adapt to any changes global warming causes? Personally, I think it will be somewhere in between. Trying to eliminate carbon output cold turkey would be more costly than adapting to the changes from global warming. But not doing anything about carbon output and focusing solely on adaptation would probably be more expensive than a little up front cost on energy research right now.

-Jeff

[end of e-mail]

If I get any responses from them that show anything I wrote to be wrong, I'll be sure to add it here. I also let both of them know that I was putting a copy of this here on my blog, so maybe they'll post their comments here.

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