Category Archives: Science

Science and Christianity: A Dangerous Mixture

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What is the overlap between science and Christianity? Let’s contrast an old-school theologian’s approach to science with what passes for an honest following of the scientific evidence today.

Old school approach

Georges Lemaître, a Roman Catholic priest and cosmologist, suggested that the universe is expanding before there was any measurement of it, and he proposed what became the Big Bang theory. Years later, in 1951, the pope celebrated the Big Bang as scientific support for God’s declaration in Genesis, “Let there be light.” Science was providing evidence for Christianity!

Lemaître soon corrected the pope, so the story goes, arguing that it’s unwise for Christians to mix science and religion. He was making a “live by the sword, die by the sword” argument: if you embrace science when it can be used to point to God, consistency demands you also admit every place where science argues against God. These would be, for example, where science provides natural explanations well supported by evidence that make God unnecessary. Scientific conclusions can change, he argued, so don’t imagine that a pleasing result is immoveable granite on which you can build your Christian worldview.

Modern apologists

Evangelical apologists like William Lane Craig, Lee Strobel, Frank Turek, and more apparently didn’t get the memo. Unconcerned about the consequences, they eagerly point to science-based arguments like the Kalam Cosmological Argument, the Design Argument, and the Fine-Tuning Argument. The last thing they would do is say, “If you show my scientific claims to be false, then I will no longer believe.” (They don’t even say, “If you show my scientific claims to be false, I won’t use them anymore”!) For them, scientific claims are, like Donald Trump’s associates, celebrated when useful and discarded like a used tissue when not.

Lemaître said that a scientific foundation demands a commitment. If a scientific conclusion were a part of his religious foundation, then his faith should be shaken if that conclusion were overturned. His solution: don’t make it part of your foundation. Contrast that with modern apologists’ solution, which is to discard any no-longer-helpful foundational claims and hope no one notices. In fact, the science never was part of the foundation of their beliefs—their foundation is unfalsifiable. They just trot the science out and hope that someone else would make it part of their foundation.

I see two possibilities. One is that these modern apologists agree with Lemaître that these scientific arguments shouldn’t support their own Christian belief (despite pushing those arguments on others). The other possibility is that there’s some cognitive dissonance in which they simultaneously take support from the scientific arguments while making their own faith unshakable if those arguments later fail.

Lemaître was consistent—these arguments didn’t support his faith, and he discouraged anyone from pushing them on others. Ah, for the old days. . . .

Consistency for apologists?

Apologists throw puzzles at atheists like “What caused abiogenesis?” or “What caused the Big Bang?” or “How can you explain the fine tuning of the universe?” Scientists have tentative answers (such as “We have intriguing ideas but nothing definite,” “Quantum events like the Big Bang don’t need causes,” and “The multiverse,” respectively), and when the consensus becomes strong enough, the apologists will ignore those puzzles and look for more. But being an apologist means never having to say you’re sorry, and they never let evidence against their position ruin their day. Their belief is unfalsifiable, and they have a secret weapon: cherry picking the scientific evidence to support their preconception.

As science pushes into new frontiers, there will always be new questions, but then their position becomes, “Science has unanswered questions; therefore, God.”

If Lemaître refused to support his faith with scientific arguments, I don’t know if he relied instead on nonscientific arguments like “the Bible has many manuscript copies” or “the resurrection is supported by much historical evidence” or the Shroud of Turin. I’m guessing not since historic evidence could be undercut just like scientific evidence (for example, by the argument that Mormonism makes a far better historic case than Christianity). Comparing him to modern evangelicals, Lemaître would look like a quaint throwback, though one who was gratifyingly consistent.

I wouldn’t find a faith-only argument compelling, but then the science-based arguments aren’t compelling either, especially when apologists make clear that they don’t build their own faith on them. If they don’t, why should I?

Science is a harsh mistress, and Lemaître was careful to stay on her good side. Evangelical apologists want to turn her into a prostitute.

See also:

As far as I can see, such a theory [as the Big Bang] remains
entirely outside any metaphysical or religious question.
It leaves the materialist free to deny any transcendental Being.
— Father Georges Lemaître, originator of Big Bang idea

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Image from Jayson Hinrichsen, CC license
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The Backfire Effect: When Accurate Information Is a Mistake

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Barack Obama is a Christian. He easily passes the tests you’d give to anyone else: he uses Christian language, he goes to church, and (most importantly) he says he’s a Christian!

It’s been fact checked, as if that would be necessary. Turns out that, yes, he’s a Christian.

But you wouldn’t be so sure if you took your conclusion from polls. In March 2008, before Obama was elected president, polls showed 47% of Americans accepted that he was Christian, 12% said Muslim, and 36% didn’t know. With time, this groundless bias should dissolve away, right? Nope. Four years later, the 2012 poll showed similar results.

Another poll in Mississippi found 12% saying Christian and 52% Muslim (and 36% Don’t Know). Among “very conservative” voters, it was 3% Christian, 58% Muslim, and 39% Don’t Know. That was in 2012. In America, where Article VI of the Constitution forbids a religious test for public office and the technology is widely available to look stuff up.

This example shows that we well-educated moderns don’t always accept obvious facts. Who could then doubt that first-century Christians might not have recorded events with perfect accuracy? But that’s just a corollary observation. I want to instead explore how this deeply embraced misinformation gets in our heads and stays there.

Backfire effect

The natural response for skeptics like me is to suppose that misinformed people simply don’t have the correct facts. People are eager to know the truth, and if we provide them with the facts, the misinformation will vanish.

In some cases, this is true. A correction that doesn’t push any buttons can work. It’s easy to accept a more efficient driving route to work or a new accounting policy. In situations like politics, however—as the “Obama isn’t a Christian” example shows—things are more complicated. And here’s the crazy thing: presenting people with the correct information can reinforce the false beliefs. That’s the Backfire Effect.

One helpful article (“How facts backfire”) notes that it’s threatening to admit that you’re wrong, especially where one’s worldview is involved, as with politics and religion. The article calls the Backfire Effect a defense mechanism that avoids cognitive dissonance. Cognitive dissonance is “the mental discomfort (psychological stress) experienced by a person who simultaneously holds two or more contradictory beliefs, ideas, or values.”

In reality, we often base our opinions on our beliefs, which can have an uneasy relationship with facts. And rather than facts driving beliefs, our beliefs can dictate the facts we chose to accept. They can cause us to twist facts so they fit better with our preconceived notions.

It gets worse. I’ve written before about the critical but often overlooked difference between confidence and accuracy in memories, how a confident memory isn’t necessarily an accurate one. Studies of the Backfire Effect show that those people most confident in their grasp of the facts tended to be the least knowledgeable about the topic. That is, those most in need of correcting their beliefs are least likely to do so.

This isn’t just an academic issue. These people are voters, and their ignorance affects public policy.

(As an aside, this is related to the Dunning-Kruger effect in which more competent people rate their ability less than it actually is, while less competent people do the reverse. The hypothesis is that the less competent people were too incompetent to appreciate their own incompetence.)

How can we humans be as smart as we are but have this aversion to correct information? The human brain seems to seek consistency. It’s mentally easy to select confirming information and ignore the rest. Reevaluating core principles is difficult and stressful work.

Let’s not be too hard on ourselves, though. If we had to continually reevaluate everything, we’d never get out of bed in the morning. Cognitive shortcuts make sense, usually, but let’s keep in mind the limitations of our mental computer.

Silver lining

I do take some small delight in this, however. Political conservatives today grant themselves the privilege of picking and choosing their facts, rejecting Obama’s religion as well as evidence for climate change, evolution, and any other inconvenient fact. But then they undercut their own conservative Christian arguments when they insist that the authors of the New Testament were scrupulous journalists.

Nope—if conservative Christians care little for the truth today, they can’t insist that first-century scribes were any more careful.

Continue with a post discussing ways to bypass the Backfire Effect.

The door of a bigoted mind opens outwards
so that the only result of the pressure of facts upon it
is to close it more snugly.
— Ogden Nash

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(This is an update of a post that originally appeared 12/8/14.)

Image via Liji Jinaraj, CC license

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Maybe People CAN Change Their Minds After All

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confirmation bias backfire effectI’ve written before about the discouraging studies that illustrate the Backfire Effect. If someone has a belief that is objectively wrong—that is, a belief that an unbiased observer equipped with all relevant facts would judge as false—giving the correct information isn’t likely to get them to change their mind.

But it feels so right! The other guy has come to the wrong conclusion, and once I give him the correct facts, he’ll cheerfully thank me and switch to the correct opinion, right? That sounds reasonable, but no—he will instead very likely double down on the false belief. Changing one’s opinion is painful, and this response to his error only makes the problem worse.

I explored approaches that minimize the Backfire Effect, but a recent article, “Why Facts Don’t Change Our Minds” by Elizabeth Kolbert, has an approach that should be more productive. But more on that shortly. Getting there is an interesting journey.

Study 1: biased weighing of data

The article gives a number of studies that reveal the embarrassingly inept way our minds sometimes work. In one study, half of the participants were in favor of capital punishment and half not. Each participant was given two studies that argued the two sides of the issue. These studies were actually made up, but they presented data that was equally compelling. Participants reported that the one that supported their own opinion was far more compelling than the other (this is confirmation bias). Afterwards, they were asked about their views. Unsurprisingly, they were more entrenched than they’d been at the start. This is the Backfire Effect.

Why are we susceptible to poor thinking?

This human failing enables America’s new vogue of alternative facts. But since this thinking isn’t logical, why do people do it? Why are they biased toward confirming evidence, and why does presenting disconfirming evidence force them to double down?

Since this is pretty much universal, it’s an evolved trait, but what value could it have to outweigh the downsides? Some researchers say that it developed in a society where humans had to work together. A cooperating society wants to encourage members who contribute, but it must punish freeloaders—possibly even to the point of exile. That’s a substantial punishment because, in a primitive society, living on your own is much harder than being a contributing member in a tribe.

Human reason didn’t evolve to weigh economic policy options or evaluate social safety nets, but, according to this theory, it evolved to defend one’s social status. Winning arguments is important, and self-confidence helps. Doubting your position is not a good thing. The thoughtful tribal member who says, “Well, that’s a good point—maybe my contribution to the group has been sub-par” risks exile.

(Another area of thought where we are surprisingly poor is probability—surprising because we seem to bump into simple probability questions all the time. I’ve written about the Monty Hall Problem here and about simple puzzles that reveal our imperfect thought process here.)

Study 2: explain your answer

In this study, graduate students were first asked to evaluate their understanding of everyday devices—toilets, zippers, cylinder locks, and so on. Next, they were asked to write a detailed explanation of how the devices worked. Finally, they again rated their understanding of these devices. Being confronted with their incompetence caused them to lower their self-rating.

It’s easy to think of the user interface alone and overestimate our understanding of how it works inside. This encapsulation is important for progress—you don’t understand how a calculator works but you know how to operate it. The same is true (for most of us) for a car, a computer, a cell phone, or the internet. We know how to buy hamburger or a suit, but we don’t understand the particulars of how they got to the store. This encapsulation extends into public policy—we (usually) don’t understand the intricacies of policy proposals like cap and trade or trade deals like NAFTA or TPP. Instead, we rely on trusted politicians and domain experts to convince us of the rightness of one side of the issue.

Study 3: policy questions

That brings us to one final study, modeled on the last one. Participants were asked their opinions on policy questions like single-payer health care or merit-based pay for teachers and then were asked to rate their confidence in their answers. Next, they were asked to explain in detail the impact of implementing each proposal. Finally, they were asked to reevaluate their stance. Having just struggled to explain the details of their favored proposal, they dialed back their confidence.

This finding may be relevant to our interactions with people arguing for scientific or historical claims like Creationism or the Resurrection, or for social policies like making abortions illegal or “natural marriage.” Instead of pushing back, ask them to explain their position. Let them marinate in their own confusion. Avoid the snarky retort (tempting, I know), which would trigger the Backfire Effect.

This research is equally applicable to ourselves. Find or create opportunities to explain how your favored policy, if implemented, would work and then ask yourself how this exercise changes your opinion. Is it still a no-brainer? Or have you uncovered obstacles that might make success more elusive?

Let me end with one final cautionary observation. When you ask someone, “Do you accept evolution?,” you may see this as a straightforward question about opinion or knowledge. For some, however, you’re asking about who they are. “I am a Christian,” they think, “and my kind of Christian rejects evolution.” Your straightforward question becomes in their mind, “Do you reject Jesus Christ as Lord and savior?,” to which the answer is, obviously, No. Other personal questions potentially fall into the same trap—questions about abortion or same-sex marriage or even climate change.

There is security in obscurity.
Precision invites refutation.
— Walter Kaufmann

Image credit: Wesley Eller, flickr, CC

A Response to Evolution Deniers: How Complex Comes from Simple

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evolution creationists simple complexIn a recent post, I responded to the Creationist challenge, “DNA is a program, programs demand a programmer, and that programmer is God” Let’s turn to a related idea, that DNA is too complex to have evolved naturally.

DNA (or RNA) becoming more complex, from the first simple cells four billion years ago to humans and other animals today, is explained by evolution, but conservative Christian groups often dogmatically reject evolution. They say that it is incompatible with God creating life in Genesis (in two incompatible stories, but never mind that). Adam didn’t evolve from earlier apes, they tell us—that would be yucky. No, God created Adam from dirt, which is far more dignified. And we know that Eve was made from Adam’s rib because it’s right there in Genesis (leading to the belief, which survives, that men have one fewer ribs than women).

Curiously, they never seem to be troubled by quantum physics, which is far more counterintuitive.

Let’s explore a few examples besides evolution where complex comes from simple. The well-known Fibonacci sequence is very simple. Each term is the sum of the two previous terms: F(n + 2) = F(n + 1) + F(n). After {1, 1} as the first two terms, we get:

1 + 1 = 2

2 + 1 = 3

3 + 2 = 5

5 + 3 = 8

8 + 5 = 13

And so on. It’s trivially simple, and yet entire books have been written on this simple series and its applications. As one example, the ratio of consecutive terms in the Fibonacci series becomes an increasingly good approximation to phi (φ), the golden ratio. Expressed formally:

Phi 2

And then phi itself is a fascinating number about which entire books have been written. To take just one example of many, phi (φ = 1.618 . . .) is the only number that if you take off the initial one (0.618 . . .) and then invert it (1/0.618 . . .) you get the original back: φ – 1 = 1/φ.

There are many more examples of complex coming from simple, some of which you are already familiar with.

  • Crystals and snowflakes are complex but formed from simple physical principles and laws.
  • Simple equations can form beautiful, complex, fractal artwork as Julia sets.
  • The harmonograph (typically, a pen is controlled by two pendulums as it draws on paper) was invented in the 1800s. A Spirograph creates similar art.
  • John Horton Conway’s Game of Life is a two-dimensional cellular automaton with three simple rules. The general category of cellular automata also create complex patterns with simple rules.
  • The members of social insect colonies—ants, termites, bees—don’t have large brains for complex algorithms, and yet they still create complex hives and nests. “A single ant or bee isn’t smart, but their colonies are,” as National Geographic put it. Starlings are famous for their swarms (“murmurations”) that appear to act as a single organism, and many fish swarm. Simple rules govern both.
  • A piano has 88 keys but can create a vast number of pieces of music.
  • The Periodic Table has 94 naturally occurring elements. From these millions of compounds are possible. Only 19 elements are essential for human life, but these make the thousands of chemicals that are metabolized as food and converted into thousands more to make a healthy human.
  • Mathematics has a small set of axioms (a statement declared true because of evidence, not because it derives from simpler axioms) from which derive its fantastic complexity—algebra, geometry, trigonometry, calculus, topology, group theory, linear algebra, probability and statistics, number theory, and so on.
  • Pulsars emit a beam of radiation at very precise intervals, measured in milliseconds or seconds. From our vantage point, they’re like a lighthouse. The pulses were so curiously regular that an intelligent source was considered, first as interference from the earth and then as a signal from an alien intelligence. We now know that pulsars are rotating neutron stars that emit beams of radiation from their poles.

That the complex can come from the simple is no proof that DNA wasn’t made by God or that there is no God, but it does illustrate that complexity can be nicely explained with natural means.

Creationists are forced to the very brink of accepting evolution when they agree that antibiotic resistance is caused by random mutation and natural selection acting on bacteria. Add more time (not just years but millions of years), and you get the diversity of life that you see on earth. Somehow Creationists imagine an unexplained shield that prevents one species from eventually becoming another.

At best, they propose an argument from ignorance: Wow—look at how DNA works. What could’ve caused that?? This is no evidence for God. And what does it say of their arguments that this argument from incredulity is in their arsenal? A god worth believing in wouldn’t be hidden.

If you pretend that your problems are already solved,
you have no motivation to solve them.
— Scathing Atheist podcast #76

Image credit: Wikimedia

“DNA is a Program, and Programs Demand a Programmer”: a Response

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DNAOne popular science-y argument for God is that DNA is information. In fact, it’s not only information, it’s a software program. Programs require programmers, so for DNA, this programmer must be God.

For example, Scott Minnich, an associate professor of microbiology and a fellow at the Discovery Institute, said during the 2005 Kitzmiller v. Dover trial, “The sophistication of the information storage system in nucleic acids of RNA and DNA [have] been likened to digital code that surpasses anything that a software engineer at Microsoft at this point can produce.” Stephen Meyer, also of the Discovery Institute, said, “DNA functions like a software program. We know from experience that software comes from programmers.”

I wonder why DNA brings anything new to the conversation. The idea that the human body is like a designed machine has been in vogue ever since modern machines. The heart is like a pump, nerves are like wires, arteries are like pipes, the digestive system is like a chemical factory, eyes and ears are like cameras and microphones, and so on. But let’s ignore that and respond to the apologist’s claim that programs (in the form of DNA) require programmers.

Nature vs. machine

As a brief detour, notice how we tell natural and manmade things apart. Nature and human designers typically do things very differently. This excerpt from my book Future Hype: The Myths of Technology Change explores the issue:

By the 1880s, first generation mechanical typesetters were in use. Mark Twain was interested in new technology and invested in the Paige typesetter, backing it against its primary competitor, the Mergenthaler Linotype machine. The Paige was faster and had more capabilities. However, the complicated machine contained 18,000 parts and weighed three tons, making it more expensive and less reliable. As the market battle wore on, Twain put more and more money into the project, but it eventually failed in 1894. It did so largely because the machine deliberately mimicked how human typesetters worked instead of taking advantage of the unique ways machines can operate. For example, the Paige machine re-sorted the type from completed print jobs back into bins to be reused. This impressive ability made it compatible with the manual process but very complex. The Linotype neatly cut the Gordian knot by simply melting old type and recasting it. . . .

As with typesetting machines, airplanes also flirted with animal inspiration in their early years. But flapping-wing airplane failures soon yielded to propeller-driven successes. The most efficient machines usually don’t mimic how humans or animals work. Airplanes don’t fly like birds, and submarines don’t swim like fish. Wagons roll rather than walk, and a recorded voice isn’t replayed through an artificial mouth. A washing machine doesn’t use a washboard, and a dishwasher moves the water and not the dishes.

With DNA, we again see the natural vs. manmade distinction. It looks like the kind of good-enough compromise that evolution would create, not like manmade computer software. Not only does the cell have no CPU, the part of a computer that executes instructions, but we’ve created genetic software that changes and improves in an evolutionary fashion. This software can be used for limited problems, but it must be treated as a black box. It looks nothing like the understandable, maintainable software that humans create.

As another illustration of the non-software nature of DNA, the length of an organism’s DNA is not especially proportionate to its complexity. This is the c-value enigma, illustrated with a chart comparing DNA length for many categories of life here.

We actually have created DNA like a human programmer would create it, at least short segments of it. The Craig Venter Institute encoded four text messages into synthetic DNA that was then used to create a living, replicating cell. That’s what a creator who wants to be known does. Natural DNA looks . . . natural. (See more on the broken stuff in DNA here and how this defeats the Design Hypothesis here.)

If God designed software, we’d expect it to look like elegant, minimalistic, people-designed software, not the Rube Goldberg mess that we see in DNA. Apologists might wonder how we know that this isn’t the way God would do it. Yes, God could have his own way of programming that looks foreign to us, but then the “DNA looks like God’s software!” argument fails.

Consider more broadly this supposed analogy between human design and biological systems.

  • Human designs have parts purposely put together. We know they are designed because we see the designers and understand how they work.
  • Biological systems live and reproduce, and they evolve based on mutation and natural selection.

But these traits of human designs don’t apply to biological systems, and vice versa. So where is the analogy? The only thing they share is complexity, which means that the argument becomes the naïve observation, “Golly, biological systems are quite complicated, so they must be designed.” This is no evidence for a designer, just an unsupported claim that complexity demands one. And why think complexity is the hallmark of design? Wouldn’t it be elegance or something similar?

The software analogy leads to uncomfortable conclusions

The DNA = software analogy brings along baggage that the Christian apologist won’t like. The apologist demands, “DNA is information! Show me a single example of information not coming from intelligence!”

This makes them vulnerable to a straightforward retort: Show me a single example of intelligence that’s not natural. Show me a single example of intelligence not coming from a physical brain (h/t commenter Benjamin Bastin). These apologists are apparently quite comfortable with things that have no precedent (and far too comfortable with things that have no evidence, like the supernatural).

Actually, we find information in lots of nonliving natural things. The frequency components of starlight encodes information about that star’s composition and speed. (h/t commenter Greg G.) Tree rings tell us about past precipitation and carbon-14 fluctuation. Ice cores and varves (annual sediment layers) also reveal details of climate. Smell can tell us that food has gone bad or if a skunk is nearby.

Genetic software is another example of information creation. The apologist will object that genetic software doesn’t qualify because it’s created by humans. That’s true, but the software is simply a concrete demonstration that proves the idea. Drop the software and make it a thought experiment.

The popular DNA = software analogy should be retired for lack of evidence.

Next: A response to evolution deniers: how complex comes from simple

To ask an atheist what evidence would change their mind
is to admit we’re in a naturalistic universe
and thus make the question void.
— commenter primenumbers

Image credit: AndreaLaurel, flickr, CC

Do Souls Exist? Science Says No.

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soul physicsThis photo is of Phineas Gage, a railroad worker who, in 1848, was tamping down black powder with an iron rod when the powder exploded and shot the rod through his head, coming in under his left cheekbone and out the top. This picture shows him with the rod, his “constant companion.” (To see his skull and a recreation of where the rod went, go here.)
Mind/brain connection
What happens when much of the left frontal lobe of a person’s brain is destroyed? Gage was one of the first examples by which modern medicine saw how cognition and personality—what we think of as the mind—are connected to the physical brain.
Modern science has continued to find connections between various parts of the brain and different functions, and the mind is often defined as simply what the brain does. For example, Henry Molaison had part of his brain surgically removed in 1953 to treat epilepsy. An unintended consequence of the surgery was a type of amnesia in which he could remember events before the operation, but he couldn’t form new memories.
Another example is Clive Wearing, a British musicologist who got amnesia from encephalitis in 1985. His long term memory is poor, and he can’t remember new events for more than half a minute. He feels like he is continually waking up. He can still play the piano, though he has no recollection of ever being taught.
Then there’s Klüver-Bucy Syndrome, the rare result of some kinds of brain damage from surgery or disease. Or aphasia, the loss of the ability to speak, which usually comes from strokes. Or the kinds of personality and memory loss caused by Alzheimer’s and other kinds of dementia. Or even prions, the misshapen proteins that cause BSE (“mad cow disease”) in cattle and similar degenerative brain diseases in humans. These are all examples of the “mind” being changed due to physical damage to the brain.
The “mind” is a useful idea, but this close connection between the brain and mental function leaves no room for a physical mind—something separate from the brain—to hide. The same is true for the soul. It’s a useful word to refer to someone’s essence or moral character, but there is no evidence that the soul exists as anything more than an abstract concept.
The brain behaves exactly as if it’s all that there is, not that it is simply the shoebox in which the soul is stored. How could an injury to the shoebox affect its contents, when the soul is immutable and will be good as new in heaven?
When you change your mind, the old opinion doesn’t go anywhere, it just stops existing in your mind. Why should the soul be any different?
What does physics say?
Physics isn’t a field that usually has much to say about the soul, but a video by physicist Sean M. Carroll of CalTech makes the intriguing argument that physics shows that souls don’t exist.
There’s plenty of physics that we don’t yet understand, he says, but the physics of our Newtonian world is all understood. For example, you don’t need to understand string theory to work in chemistry. Any physics that operates in our world would be known to us by now, which leaves no room for the supernatural.

Could new particles hide from our view? Sure, but only if they were (1) very weakly interacting or (2) too heavy to create or (3) too short-lived to detect. In any of those cases, the new particle would be irrelevant to our everyday lives. (Source)

Everyday physics is understood. We’re done. It’s nothing more than quarks, mass, and the fundamental forces.
The physics that remains are non-everyday physics (dark matter, dark energy, quantum gravity, origin of the universe, etc.) and complicated systems that are the result of the understood physics (superconductivity, turbulence, cancer, consciousness, etc.).
Compare physics with chess. Knowing the rules of chess doesn’t make you a grandmaster, but it does constrain the kinds of games you can play. Any games in which the pawn moves like a queen, for example, can be simply ruled out.
In physics, we know the rules of the everyday world, and this constrains the kinds of things that make sense. We know enough to simply rule out astrology, claims of clairvoyance, ESP, life after death, homeopathy, and other supernatural claims. If these claims were true, we would know that already. If you claim that a soul exists and lives on in the afterlife, tell us the physics by which the soul moves to the afterlife.
The ideas that the soul actually exists and that the mind is separate from the brain belong back to the time when demons were said to cause mental illness.

What is freedom of expression?
Without the freedom to offend,
it ceases to exist.
— Salman Rushdie

(This is an update of a post that originally appeared 5/4/13.)
Photo credit: Wikipedia