Does it damage children to teach them biblical creationism? What are the costs of denying evolution, one of biology's core tenets?
Those questions were asked Tuesday night, in a live debate between best-selling Christian author Ken Ham and Emmy Award-winning educator Bill Nye ("the Science Guy") at the Creation Museum of Petersburg, Ky.
Here's a video feed of their debate. Below that are highlights from their exchanges:
Update Thursday, Feb. 6: Recap And Analysis
Interest in points raised in the debate has generated spirited responses and criticisms online. You can read about some of those views in a new post from Thursday.
The debate saw Nye and Ham discussing natural laws and scientific research, along with astronomy, geology and the number of animal species on Earth – but with markedly different views. Both of them talked about Mount St. Helens and the Grand Canyon, for instance, without agreeing on those landmarks' places in history.
"None of us saw the sandstone or the shale being laid down," Ham said. "Bill Nye and I have the same Grand Canyon."
"It's not the evidences that are different," Ham says. He calls it a "battle" over viewpoints.
"We are standing on millions of layers of ancient life," Nye said. "How could those animals have lived their entire life, and formed these layers, in just 4,000 years? There isn't enough time since Mr. Ham's flood for this limestone, that we're standing on, to have come into existence."
The wide-ranging debate had a format of opening statements followed by 30-minute presentations, then by rebuttals and counter-rebuttals. The program ended with an audience Q&A session.
Update at 9:30 p.m. ET: Question Time
The debate enters a Q&A session with audience-submitted questions at around the 1:50 mark in the video (that's one hour, 50 minutes). We'll break away from the action now, but the video's here for you to watch.
An early moment from that part of the program might be our favorite of the night. It came as Nye responded to a question about how the atoms that created the Big Bang came to be there. He illustrated the bang with his hands and an explosive sound — before correcting himself.
"Except it's in outer space; there's no air," he said, going on to mime the same explosion again, in silence.
As for his answer, Nye said, "This is the great mystery; you've hit the nail on the head. What was before the Big Bang? This is what drives us, this is what we want to know. Let's keep looking, let's keep searching."
Feel free to take up issues from the rest of the Q&A portion in the comment section.
Update at 9:15 p.m. ET: Nye's Counter-Rebuttal
"Thank you, Mr. Ham. But I am completely unsatisfied. You did not, in my view, address this fundamental question: 680,000 years of snow-ice layers, which require winter-summer cycle."
There simply hasn't been enough time to generate the species on Earth, Nye says.
"Then, as far as Noah being an extraordinary shipwright, I'm extraordinarily skeptical," Nye says. He cites his own family's background in New England, where people spent their lives learning how to build ships.
"It's very reasonable, perhaps, to you that Noah had superpowers and was able to build this extraordinary craft with seven family members," Nye says. "But to me, this is just not reasonable."
When scientists make assumptions, Nye says, "they're making assumptions based on previous experience. They're not coming out of whole cloth. So, next time you have a chance to speak, I encourage you to explain to us why we should accept your word for it that natural law changed just 4,000 years ago — completely — and there's no record of it.
"You know, there are pyramids that are older than that. There are human populations that are far older than that — with traditions that go back farther than that. And it's just not reasonable to me that everything changed 4,000 years ago."
Nye also asks Ham to discuss the billions of people on Earth, including Christians, who don't agree with Ham's point of view about the planet's age.
"So, what is to become of them, in your view?" Nye asks.
Update at 9 p.m. ET: Ham's Counter-Rebuttal
Ham clarifies that the wood he discussed was encased in the basalt.
"I would also say that natural laws haven't changed," he says. "As I talked about, we have the laws of logic, the uniformity of nature — and that only makes sense within a biblical worldview anyway."
Ham also says the views he's putting forth aren't just his own — and he notes that there are "lots of creation scientists who agree with exactly what we're saying."
And Ham takes issue with Nye's earlier point — that animals such as lions have long, sharp teeth, meaning they cannot have sailed in the ark as vegetarians — by referencing several animals, from pandas to bats, that have sharp teeth but don't eat meat.
Ham defends Noah's ship-building ability, saying he hasn't met him — and neither has Nye.
He goes on to say it seems Nye has confused the terms "species" and "kind" — the latter being a word creationists use to describe groups of animals.
"We're not saying species got on the ark," Ham says. "We're saying kinds."
He goes on to discuss "the horizon problem" that has to do with the speed of light and background radiation in the universe.
"Everyone has a problem concerning the light issue," he says.
Update at 8:48 p.m. ET: Nye's 5-Minute Rebuttal.
"Let me start with the beginning," Nye says. "If you find 45-million-year-old rock on top of 45-thousand-year-old trees, maybe the rock slid on top. Maybe that's it," he says. He flattens his palms one on the other, for emphasis.
"That seems a much more reasonable explanation than, 'It's impossible.' "
Nye goes on to discuss dating rocks, saying one question he and his peers think of as a mystery, or an "interesting" fact, is why asteroids all "seem to be so close to the same date in age, 4.5, 4.6 billion years."
He says Ham takes the Bible — "as written in English" and translated many times — as more accurate and reasonable than "what I and everybody in here can observe."
"That, to me, is unsettling. Troubling," Nye says.
"As far as, 'You can't observe the past,' I have to stop you right there," Nye says. "That's what we do in astronomy. All we can do in astronomy is look at the past.
"By the way, you're looking at the past right now," he tells the audience, "because the speed of light bounces off of me and then gets to your eyes. And I'm delighted to see that the people in the back appear just that much younger than the people in the front."
Nye tells Ham that in terms of their views, "This idea that you can separate the natural laws of the past from the natural laws that we have now, I think, is at the heart of our disagreement.
"I don't see how we're ever going to agree if you insist that natural laws have changed. It's... for lack of a better word, it's magical."
Update at 8:30 p.m. ET: Ham's 5-Minute Rebuttal
"Bill, if I was to answer all of the points that you brought up, the moderator would think I'm going on for millions of years. So I can only deal with some of them," Ham says.
He decides to discuss the age of Earth.
"The Bible says God created in six days," Ham says. He describes how the genealogies in the Bible are added up, with the help of a slide.
"From Adam to Abraham — you've got 2,000 years from Abraham to Christ, 2,000 years from Christ to the present, 2,000 years," Ham says, "that's how we reach 6,000 years," he says.
But to people who say Earth is 4.5 billion years old, Ham says "we certainly observe radioactive decay," but "when you're talking about the past, we have a problem."
He cites a basalt layer found in Australia in which wood was found to have been a wildly different age from the basalt it had been in.
"My point is, all these dating methods give all sorts of different dates," Ham says.
Update at 8:25 p.m. ET: Nye On ... Well, Science
According to YouTube, more than 530,000 people are watching the live debate toward its end.
Nye takes up the wealth of species and stars. He notes that there are billions of stars — too many to have arrived in the past 4,000 years, he says. And he notes how astronomers puzzled over why stars are seen to be moving apart.
Then he relays how researchers found "cosmic background sound" in space that astronomers had predicted would be the remnants of the Big Bang.
"Astronomers running the numbers, doing the math," predicted it exactly, he says. He later adds, "You've got to respect that. It's a wonderful thing."
Update at 8:10 p.m. ET: Nye On Grand Canyon And Fossils
Nye discusses layers of ancient stone and sediment in places such as the Grand Canyon, and the various animals you'll see there. He says there is no evidence of intense churning and bubbling that an epic flood would bring.
"This is what geologists on the outside do," he says, "studying the rate at which soil is deposited" and turns to stone.
"And by the way, if this great flood drained through the Grand Canyon, wouldn't there have been a Grand Canyon on every continent?" Nye asks.
He then discusses the layers of animal fossils in the layers — from rudimentary sea animals to "the famous trilobites" and clams, oysters, mammals.
"You never, ever, find a higher animal mixed in with a lower one," he says. "You never find a lower one trying to swim its way to the higher one."
Update at 8 p.m. ET: Nye's Presenation
Nye begins his portion by saying, "Thank you very much. And Mr. Ham, I learned something. Thank you."
Then he displays a rock he found that day in Kentucky, saying many in the area contain coral fossils.
"We are standing on millions of layers of ancient life," Nye says. "How could those animals have lived their entire life, and formed these layers, in just 4,000 years? There isn't enough time since Mr. Ham's flood for this limestone, that we're standing on, to have come into existence."
Nye then describes how scientists go to the Earth's poles to drill ice cores of snow ice.
"Snow ice forms over the winter," he notes, adding, "We find certain of these cylinders to have 680,000 layers - 680,000 snow winter/summer cycles.
"How could it be that just 4,000 years ago, all of this ice formed?" Nye asks.
He then illustrates his point, saying that to make sense, there would need to be 170 winter-summer cycles each year.
"Wouldn't someone have noticed that?" he asks with a laugh. "Wow."
Earlier, as moderator Tom Foreman bridged between the two presentations, he referred to one of Ham's slides: "When you had my old friend Larry King up there — you could've just asked him. He's been around a long time, and he's a smart guy. He could probably answer for all of us."
Update at 7:40 p.m. ET: Ham Cites 'Civic Biology'
Ham cites what he calls a widely used U.S. schoolbook from "the 1900s" that said there were five species of men. It's A Civic Biology, first published in 1914 — the book that sparked the Scopes "Monkey Trial" in Tennessee.
Those ideas "were based on Darwin's ideas that were wrong," Ham says.
He contrasts that with the Bible, which says that biologically, there's only one race of humans.
Ham says that while you can observe that Earth isn't round, "you can't observe the age of the Earth."
Update at 7:30 p.m. ET: Ham's Presentation
Instead of a prolonged back-and-forth, both men will deliver 30-minute presentations putting forth their viewpoints.
Ham once again notes that scientists can also be creationists. And he says the evidence they see and interpret is the same as other scientists.
In the case of the Grand Canyon, Ham says, "None of us saw the sandstone or the shale being laid down."
"Bill Nye and I have the same Grand Canyon," Ham says.
"It's not the evidences that are different," he says. He calls it a "battle" over viewpoints.
Then he talks about Charles Darwin.
"Darwin wasn't just thinking about species," Ham says. "Darwin had a much bigger picture in mind."
Ham says his views as a creationist conform with Darwin's views, noting cases of finches and dogs in which researchers see a single origin for the animals.
"The word 'evolution' has been hijacked," Ham says — being used for both observable changes and unobservable changes. The result, he says, is that it indoctrinates students in evolutionary belief.
Update at 7:20 p.m. ET: Nye's Opening Statement
Bill Nye begins with a family anecdote about a bow tie. Then he mentions the TV franchise CSI.
"On CSI, there is no distinction between observational and experimental science," Nye says. He says the show does not rely on "historical science" and presents actual situations.
He then mentions the Grand Canyon, and notes that fossils show animals don't mingle between eras.
"What makes the United States a world leader is our technology," Nye says.
If the U.S. focuses on science other than that accepted around the world, "we are not going to move forward" and make discoveries and innovations, Nye says.
Update at 7:10 p.m. ET: Ham's Opening Statement
After introductions and a warm welcome, Ken Ham tells the audience that he knows many of them might not agree with his point of view. But he notes that some people find his Aussie accent to be charming.
"I hope you enjoy hearing me say it anyway," Ham says.
Ham says it's wrong to assume scientists can't also believe in creationism.
"I believe science has been hijacked by secularists," he says, who seek to indoctrinate "the religion of naturalism."
He mentions several scientists whom he says believe in creationism, including genetics pioneer Craig Venter and medical inventor Raymond Damadian.
Our original post continues: