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A Post in Reply to a Comment
On my last post, there were a number of comments, but I wanted to highlight one thing Cliff wrote. I thought that this part of a comment he left was worth a full response. Quoted directly: “We can pound Gov Perry for pandering to those of his supporters who don’t believe in evolution. But, in fact, if God created the whole shebang six thousand years ago, how would we know? I don’t think that is the way it came to be, but I would not dismiss someone who did.”
Before I get into how we know the creation hypothesis is incorrect, I would like to address a more philosophical point. We live in a culture that encourages us to have strong opinions, be it about whether politician X should be president or whether Jersey Shore can be considered “culture.” Is this a good thing? Maybe, maybe not. It is good to disagree; it keeps life interesting and ensures that we are exposed to many different viewpoints. Currently in our culture, there are several disciplines of science that are subjected to this type of handling. I would argue that this does a great disservice to our society.
Unlike opinions on politicians or TV shows, scientific arguments are fundamentally data driven. This is not to say that there are not philosophical arguments; there are and they are vitally important, such as the paradigm shift from thinking that natural selection acts on the individual to thinking that it acts on genes. But ideas such as these represent new ways of interpreting existing data. For opinions to be formed, you must first examine the data and then decide whether you accept it or reject it. This is difficult enough for scientists, never mind a layperson. The explanations that make their way to pop science books, even the best of them, are too broad and too lacking in nuance. It takes a lifetime of dedicated study to truly understand even one sub-discipline. And yet we as a society are not humble when we debate scientific ideas. Everyone has an opinion, often formed on the basis of what the pundtocracy says. This is a problem for both the left and the right, whether it be about vaccines, climate change, or evolution. In science, opinions require evidence. We ignore that in our public discussions; rhetoric is far more persuasive. I cannot speak for anyone else, but I approach any new idea in science in two ways. The first is to remind myself that I am not an expert and the person who wrote the paper generally is. The second, which is how science is taught in college, is to assume that there are problems with the paper and to look for them. No ideas are perfect; reality is complicated. Even papers that are published in premiere journals have flaws. With that being said, these papers are (usually) mostly correct. It is from this approach to data that opinions about scientific ideas should be drawn.
With that introduction, I would like to directly address the comment. In particular the question “how would we know” because, while the answers are well established, they are not well known in our society and are often not taught to our children in school. Rather than deal with my own field of evolution, I would like to address the other aspect of creationism: the idea that the Earth is the product of special creation and is relatively young (say, less than 10,000 years old). This is an opinion that is common in our society; depending on what poll you look at, up to 40% of our country agrees with that sentiment. But it is an opinion not founded on data. Below I will explore three of the entirely independent lines of evidence available to all of us.
I will begin with the cosmological evidence. When we look through our telescopes, we are looking back in time. When you gaze upward at the Sun you are seeing light that is a little more than 8 minutes old. This is because of one of the laws of nature: the speed of light is finite. We know it to be roughly 186,000 miles per second. The distance light travels in one year is termed a light year. Combine this with the knowledge that space is expanding and we can form a testable hypothesis: if the universe was specially created in the past 10,000 years, we should not be able to see objects that are more than 10,000 light years away. This is, of course, not what we see when we look through telescopes. The nearest galaxy to our own, Andromeda, is 2.5 million light years away. We can infer from our observational data that the universe is roughly 13.75 billion years old. I would like to stress that this is a well established idea among scientists and there has been no evidence presented that suggests it is false.
A separate line of evidence is based on the idea of radioactive decay and the use of radiometric dating. Certain elements are unstable and thus experience what is known as radioactive decay until an atom reaches a stable state. For example, carbon-14 decays into nitrogen-14. Another example is the decay of uranium-238 through 13 other states before becoming lead-206. The reason radioactive decay is significant is that each unstable isotope has what is known as a half-life: the amount of time for half of the element in a given sample of matter to decay. Each half-life is measurable and is distinct for each element. In the case of uranium-238, its half-life is 4.5 billion years, whereas lead-210, an intermediary between uranium-238 and lead-206, has a half-life of 160 microseconds. Because there is such a wide range of radioactive clocks available, we can not only date objects found, but we can also use several independent measures to date the objects. Based on meteorites found on Earth, meteorites found on Earth that originated on Mars, and rocks found on the Moon, scientists have determined that the Earth is 4.54 billion years old. However, there is another way of corroborating this. Our Sun is what is known as a G-series star. We can observe other G-series stars with our telescopes and these stars are at varying stages of their life spans. (Over time, the size and luminosity of stars change). Because of this, we know that the Sun is 4.57 billion years into its life cycle. Soon we will be able to observe planets forming around other stars and provide a similar corroborating check on the age of the Earth.
The final line of evidence I will highlight is biological, meaning that I am far more comfortable talking about this. All life that we have discovered on Earth encodes its genetic information in DNA (with the exception of most viruses, which use RNA, but for our purposes there is no real difference). Let’s start with a simple example before we delve too far into this. Let’s assume you have one brother and one cousin. All three of you look fairly alike, but you are closer to your brother than you are to your cousin. Or put another way, you all have nearly identical DNA, but your brother’s DNA is closer to yours than your cousin’s is. Now let’s change the time scale to hundreds of millions of years. We know that all species share a common ancestry from at least 3.8 billion years ago. Obviously over time we have diverged; you do not look or behave like your pet dog, never mind the trillions of bacteria in and on your body. This is because DNA mutates over time. One particular type of mutation is relevant here: silent, also known as neutral, mutations. DNA is made up of pairings of four nucleic acids. These pairings form groups of three known as codons, which encode for particular amino acids, which in turn form proteins, which perform functions in your cells. There are twenty amino acids. If you do the math, you realize that several different codons code for the same amino acid. A neutral mutation is one in which the codon changes, but the amino acid stays the same, meaning that there will be no selection for or against the mutation because there is no change in the effect of the codon. This means that neutral mutations will accumulate in genomes at a particular rate. This concept is known as the molecular clock and is used to determine how long ago two (or more) species diverged. This is compared to fossil evidence, which is radiometrically dated, to confirm the accuracy of the molecular clock. I will leave it at one example. Our closest living relatives are chimps. We know from both molecular and radiometric clocks that we shared a last common ancestor with chimps 5 to 6 million years ago. That is a bit more than 10,000 years.
I know this has been a long post, but thank you if you are still with me. I would like to end with explaining why all of this matters to you. There are two sets of reasons. The first is the rather mundane and practical. Much of modern medicine is based on concepts that are true because evolution occurred and continues to occur. And all electronics and nuclear physics are based on the same concepts that tell us how old the universe is. In other words, our society is completely dependent on these ideas, yet many of us reject them. It matters if voters do or do not understand why overuse of antibiotics in livestock is a dangerous practice. It matters if voters do or do not understand that the next deadly virus will probably arise in poverty-stricken bushmeat hunters in Africa. And while it does not really matter if you understand how your computer works or not, society would not be able to function unless a few people did.
For the second reason, I must defer to Carl Sagan and quote him at length. In an essay published in 1995, Sagan wrote, “The truth may be puzzling. It may take some work to grapple with. It may be counterintuitive. It may contradict deeply held prejudices. It may not be consonant with what we desperately want to be true. But our preferences do not determine what’s true.” However, this is not meant to be a negative message. In his 1994 book Pale Blue Dot Sagan wrote, “…if our objective is deep knowledge rather than shallow reassurance, the gains from this new perspective [science] far outweigh the losses. Once we overcome our fear of being tiny, we find ourselves on the threshold of a vast and awesome Universe that utterly dwarfs – in time, in space, and in potential – the tidy anthropocentric [universe] of our ancestors.” Truth matters and, as we have found in every discipline of science, truth is far more inspiring than anything our ancestors imagined.
But why does our sense of awe and wonder matter? Pale Blue Dot gives an answer: “The visions we offer our children shape the future. If matters what those visions are. Often they become self-fulfilling prophecies.” To ensure the future vitality of our society we must provide our children with something to dream about. One tiny subdiscipline of one branch of science can provide any child with more than a lifetime’s worth of dreams. In his comment, Cliff wrote that he would not dismiss someone who did believe creationism. I think dismiss is the wrong word; pity perhaps. But any given individual’s beliefs matter less than society’s as a whole and a society that does not embrace the knowledge discovered by its scientists is consigning itself to decay and decline. The golden ages in history centered on science and invention. So let us inspire our children with the truth. It is the surest guide to the future success and prosperity of our country.
Andrew: Thank you for your assistance in this matter.
I know Cliff as a Catholic, and myself as one, our beliefs allow science to play a role in understanding our universe. It’s not so much evolution, that bothers me, but I guess people using evolution to dismiss that God doesn’t exist. God is supranatural, physical sciences only work on things actually within this Universe. If you read Genesis Chapter 1, it’s actually quite beautiful and amazing the ancient texts got at least the order part of things on Earth quite right. http://www.usccb.org/bible/genesis/genesis1.htm
There are writing to explain the first Chapter in the Bible or what those passages actually mean from our point of view and language/grammar differences that reflect how we got those seven days in a week. http://www.catholic.com/library/Adam_Eve_and_Evolution.asp
“Pope Pius XII warned us, “What is the literal sense of a passage is not always as obvious in the speeches and writings of the ancient authors of the East, as it is in the works of our own time. For what they wished to express is not to be determined by the rules of grammar and philology alone, nor solely by the context; the interpreter must, as it were, go back wholly in spirit to those remote centuries of the East and with the aid of history, archaeology, ethnology, and other sciences, accurately determine what modes of writing, so to speak, the authors of that ancient period would be likely to use, and in fact did use. For the ancient peoples of the East, in order to express their ideas, did not always employ those forms or kinds of speech which we use today; but rather those used by the men of their times and countries. What those exactly were the commentator cannot determine as it were in advance, but only after a careful examination of the ancient literature of the East” (Divino Afflante Spiritu 35–36). ”
I understand that atheists may have a non-existent relationship with God, but I would assume that atheists believe that they have a soul, despite no evidence we actually have them.
Science is not reason, science is just facts. Reasoning allows to figure out what is that best use of the knowledge we have, and how we should value things. Individuals based decisions on what they value, and we can have differing lines of reasoning based on our disagreements. Science does not answer purpose or meaning of our existence, all science is saying is that we exist physically.
Just this week in a discussion between Catholics and atheists, an atheist asked if God created the Universe, why did He make him? And the Catholic response is, God made us out of love. Now science can monitor and measure brain activity, of hormone and other chemicals when we are ‘in love’, but we also get these pleasurable effects when we might do something non-loving or selfish. I doubt that even the most hard-core atheists will bring himself to believe, that love is nothing more then the release of oxytocin.
My simple assertion is that over the course of humanity, many, if not all, cultures to date have offered a supernatural explanation for our existence and our purpose. Today, we scoff at the cavemans beliefs that thunder was associated to the gods, Or that the greeks thought they lived on Mt. Olympus. At best, modern cultures track how previous belief systems from 10,000 or 1,000 years prio, informed the faith systems of today.
I am a person of faith. I am not an atheist. I think it is quite arrogant of any current faith system to consider themselves the pinnicle of human understanding of the divine.
Many books, holy books, are fawned over by the masses seeking the truth. Each of those scriptures is brought to being by the hand of man. For that reason alone, I am suspect.
The only place where you and I can witness directly the hand of the divine is in the Creation itself. Science is a means, one means I may add, to examine the Creation. I’ll let the myths and fables of previous cultures inform me, via poetic license and personification, what the world around me means. Those scriptures cannot tell us what the world around us is.
Rick Perry is full of crap. Let’s be clear. Sorry if this hurts someone’s feelings. But, the Constitution isn’t a dry, 18th Century rendition of “I’m OK, You’re OK.”
Ah yes, he said: “We can pound Gov Perry for pandering to those of his supporters who don’t believe in evolution. But, in fact, if God created the whole shebang six thousand years ago, how would we know? I don’t think that is the way it came to be, but I would not dismiss someone who did.”
All of what Andrew says about our understanding of the Universe is true. I accept it. I am just saying that if there is a God out there and if he created the Universe, as opposed to it creating itself, then it is quite possible, however improbable, that at the point He created it He created a pre-history. In His act of creation he created the circumstances that allow us to reason back to the big bang.
As Andrew says, understanding all of science is a big task. A lot of folks fly on airliners and have no idea how that multi-ton machine flies through the sky. They depend on Air Traffic Control and the scientific knowledge and intuition of some weather person, and the aircrew, for their safety.
So, we are dealing with some cognitive dissonance here. Gov Perry is a modern man, with hundreds of hours piloting airplanes, for example, but “not believing in science”. Or so Keller and Krugman would have it.
That is OK with me, since I hold two views in my own mind. On the one hand, I believe in free will. On the other hand, I find nothing to convince me in science that our decisions in life are little more than “knobs and tuning” (thank you, Richard Dawkins).
Regards — Cliff
I’d like to begin by thanking you for the thoughtful comments. I’ll do my best to respond to them. Obviously these are issues where emotions can run high, but in my opinion that’s all the more reason to talk about them.
Renee, I’d like to begin with your first paragraph because you articulated two contradictory points. Catholicism is a theistic religion and maintains that God is, in at least some ways, actively involved in our lives and the physical universe. Yet you then say that this is outside the purview of science. But if a deity does act within the physical world, then it is a testable hypothesis. Even the Catholic Church agrees with this. Several years ago, it in conjunction with Harvard Medical School did a study on intercessory prayer (though it did not get the results they were hoping for). To say that God is outside the purview of science is to say that he does not act within our universe, making you a deist.
I’m not going to respond in detail to the article on evolution and Adam and Eve. I’ll hold myself to this. It is unbelievably arrogant to argue that belief trumps arrogance. Quite frankly, I find it truly astonishing that a group of elderly men with degrees in theology think they can rewrite physics and biology, though it is certainly progress from threatening to execute Galileo.
The concept of the soul has a scientific definition: mind-brain dualism. This position maintains that the physical brain and the mind (aka soul) are two separate things. It has been resoundingly rejected by psychologists and neuroscientists. The mind is the product of the brain; damage to the brain alters the mind. As for atheists in particular, it is not like there is a central set of opinions held by all atheists. You don’t even see that kind of uniformity in Catholicism or Islam. I would assume most atheists reject the concept of a soul in any literal sense, but you would have to ask a group of them what they think.
Science does include reason, in the analysis of data. Many people have argued that reason alone is enough to understand the world. This has repeatedly been shown to be false. Reason is used to interpret data, yes. But many philosophers and theologians have made arguments on reason alone. This is not a serious attempt at understanding reality.
Does science answer purpose or meaning to our existence? If the question is why we exist, that is an easy question to answer. The same goes for why the universe exists. The first is pretty intuitive once you delve enough into biology. The second involves an understanding of quantum mechanics and fluctuations in entropy, which I think deserves a full blog post. As for meaning, I will defer to Sagan again: “…knowledge is preferable to ignorance. Better by far to embrace the hard truth than a reassuring fable. If we crave some cosmic purpose, then let us find ourselves a worthy goal.”
Talking about atheists is rather irrelevant. The contradictory position you want is that of scientists. And the simple answer is yes, that is the accepted position in neuroscience and psychology. We understand the mechanics of love very well and why understand why love exists very well. While the first question is outside my area of study, the second is not and I’d be more than happy to do a post on both as well.
Jack, I would respond only to this. You suggest that there are multiple methods for understand the universe. I would respond by suggesting that you compare their records for getting things right.
Cliff, your first point is very valid. It reminds me of a very common question posed in psychology: how do we know that we are each not just plugged into a computer somewhere living in a virtual reality? Weirdly enough, computer scientists have answers to this, but I’m not smart enough to understand them. I guess I would respond by asking: why? It makes little sense to me. All the evidence points in the opposite direction. But there is no way of proving that that possibility is not true.
As for free will, that’s a rather large controversy in neuroscience at the moment. Probably the most confusing part of it is semantics; scientists can’t agree on how to define free will. But let me put it this way. Last semester I took a general psych course in which we had to write a paper on a current controversial topic is psychology. I had done some reading on free will and wanted to write about it. The problem was there really isn’t a controversy in the data. A large number of scientists posit that free will exists, but they have no evidence. And a growing body of evidence suggests it does not. But, as I said, the discussion is extremely hindered by the problems of semantics. Free will is a complicated concept and means different things to different people. But decisions are made before we are consciously aware of them. That’s the current state of affairs in a rapidly growing field.
Andrew has given a tour-de-force on this subject. I’d like to ask of anyone who believes that god is a supernatural entity existing outside of time and space, how is it possible that you–a material being existing in the “merely” natural realm–are able to ascertain knowledge of this “supernatural” god? In claiming to know that this being exists, you are claiming that you possess mental capabilities which I do not. Though our brains certainly vary in some ways, I doubt any of the differences are so large as to bring about this state of affairs.
I agree it is contradictory. God plays a role, but by His Grace.
God’s Grace is a lot like the dark matter of the universe, we know it’s there and feel its effects, but hard to prove. Grace is not a miracle, but rather describes as a ‘supranatural kick in the pants” Then there is miraculous events, in which the Catholic Church utilizes every resource. For instance the celebrity atheist, Michael Hitchens was called upon, by the Vatican as the devil’s advocate when investigating the Blessed Mother Teresa.
I have to say your presumption the elderly men with theology degrees are trying to rewrite biology is false. But I understand from your point of view, why people say such things.
Biology isn’t being rewritten by elderly men with theology degrees. It’s being celebrated through the Gospel. Also some of these priests actually have biology degrees.
Did you know we even have a priest who grew up right here in Lowell, who went Harvard and graduated with a biology degree?
You’re very busy with school. I’m also not be the best person to speak, since we have little in common in terms of shared experiences. But when you have future interests or questions, you probably need someone, just like Father Laundry. He’s that priest who grew up in Lowell and has a biology degree from Harvard.
Here’s Father Laundry’s website for later reference
http://catholicpreaching.com/index.php
You’re referring to Christopher Hitchens. The role he played is required by cannon law.
I must strongly disagree with you assessment of my statement.I did not phrase it correctly, so please allow me to correct myself. My assertion is this. There is a scientific consensus about the nature of reality. It is the result of thousands of experiments and observational studies. It is the result of generations of work by tens if not hundreds of thousands of people. The ideas that make up this consensus are testable and the ideas that remain are the ones that have withstood the strictest scrutiny. The evidence is clear. When it is not, scientists say so. What I find ridiculous is this. You have individuals with no training in the relevant field changing things to suit their own beliefs on the basis of no evidence whatsoever, in fact in the face of evidence. Or, for the ones with science degrees, they should no better; evidence is the only currency in science. In addition, there is the active practice of either selectively choosing information or outright distorting it. The bit about Adam and Eve from the first link you sent me is one of the classic examples. I apologize for not being clear in the first place.
I’m going to cut myself off there. I don’t want to get into a back and forth; I’d much rather see it from other commentors if they so wish. I just wanted to clarify my statement.
Michael:
We are really getting down to it now. It’s about “faith”—the willingness to believe in what you can’t see or prove concretely. Faith in the meaning of certain words. Faith in the truth of statements made by certain people or attributed to special persons. Faith in an explanation of what others might accept as a mystery beyond human comprehension, up to now anyway.
The questions are how does one apply faith and where does one apply it? If someone advocates making public laws or policy on the basis of faith while another someone presents logic and evidence as the basis for making laws and policy, then a chasm opens up in the decision-making process. This makes democracy even messier. Laws of course reflect values, another source of complication.
“We hold these truths to be self-evident. . . .” is a belief statement, a form of faith in a natural order of being. Actions proceed from such beliefs. This is a grand scale.
Citing religious writings to deny the validity of evolution as an explanation of how Life functions is applying a faith-based solution on a mundane level. This is biological housekeeping stuff that smart humans have figured out.
I say save faith for the cosmic questions like trying to get one’s head around the idea that the Universe is infinite or asking what becomes of one’s consciousness when brain activity ends?
A comment by Nomi Herbstman: “Jack (Kerouac) was able to channel the Holy Spirit though his words.”
My response:
“We all have the capability to reach God through our consciousness, which scientifically is more connected with the Cosmos than with our bodies, according to recent studies in quantum physics. That’s why meditation is so popular … or a walk on the beach or in the woods.”
Paul, For centuries, believers have found god to be a handy explanation for explaining what is at the moment, the unexplainable. But science has been continuously knocking down the barriers to our understanding. Previously, believers maintained that the Earth was at the center of the solar system and even the universe, as suggested by the Bible. Galileo proved that hypothesis incorrect. Then after finally having conceded this point, believers maintained that god still controlled the motion of the planets and other celestial bodies. Newton showed that this was not a matter of divine magic, but of gravitational force. Believers moved the goalposts yet again, claiming that god nonetheless created the universe. Enter the Big Bang Theory, and another round of post moving. Among science-savvy believers, it is now in fashion to maintain that god created the conditions necessary for the Big Bang.
We see the same tactics at work regarding Evolution. The rational believer knows the Earth isn’t 6,000 and that humans weren’t created in their present form by god, even though the Bible says so. Therefore it is necessary for them to say that god made Evolution happen. And on and on.
And so I suspect that if someday science does arrive at a more comprehensive understanding of the universe or is able to explain “consciousness when brain activity ends,” the goalposts will be moved once again.
“A theory that explains everything explains nothing.” – Karl Popper
In relation to the comments about theologians and biology, another problem is the use of scientific buzzwords in our daily lives where they don’t make any sense; “quantum” and “nano” are the biggest victims. Quantum physics is constantly evolving, but there are no current or future plans for it connect human consciousness with the supernatural.
The limit of science: Imagine a large black box with a mystery contained, therein. Now drill a hole through the side wall and peer in. Here, try using a flash light. What do your eyes tell you?
Now design a probe to sniff out a physical characteristic of your choice. You could pick a microphone, if you like. Does the mystery make any sounds? Meaning within the audible range for a human ear.
Now drill a million holes and fill them with a million probes, each different. What do you know? Only what you are looking for. Of course, your measuring will produce discovery which will spur new types of seeking.
But, it is a process of discovery. You can never know the exactness contained inside that box. Enjoy the discovery, but the mystery laughs at your endeavors.
Fascinating post and great discussion.
Andrew – I’m a computer scientist, so your comment about proving we are not plugged into virtual reality *right now* is an interesting one to me. Do you have the papers on that?
Similarly, as a (weak) atheist, I do not believe in the soul. I’m not big on believing strongly in and of itself, either…hence why I don’t feel the need to evangelize atheism. However, when I was in school, I took a course called “Minds and Machines” that was a computer-science-meets-philosophy class. One question that I bizarrely found myself at odds with much of the rest of the class on was the issue of free will. I outright don’t believe in it, the way it is often presented.
In computer science, we study two sorts of algorithms: deterministic ones and non-deterministic ones. The former category, the result is directly calculable from the inputs. Running the same program over and over with the same data gives the exact same answer every time. Non-deterministic algorithms are everything else.
The issue is, in software, a non-deterministic algorithm is a deterministic algorithm for which you have incomplete data – you can’t see the whole picture. That “random number generator” you find online…the numbers are not really random. They’re based on hardware states you have no insight into. Other times, programs are said to be non-deterministic because the Operating System gets in the way and does something that you don’t expect, changing the order in which code runs, for example. That’s different than immeasurable.
I would like to know the science behind why we wouldn’t expect the human mind to behave precisely the same way? The brain is an object governed by the rules of physics. Unless highly complex quantum math comes into play, my understanding is that there should be a measurable chemical and physical state of the brain at any time that should allow you to precisely determine what that person will do in a given situation (theoretically, the reality is it is still far too complex). If you ran that moment in time over again, it would never be different. Therefore, there is no free will. The universe is one giant wind-up toy.
Depressing. Or maybe when you have a hammer, you see everything as a nail. Or when you work computers, you see everything as a deterministic finite state machine. ;-)
I don’t have a paper, though I would be willing to try and track one down. I got the reference from Sean Carroll’s blog (the physicist not the biologist). He was writing about a conference he attended at Google.
Here is the relevant quote. If you could explain what it means I would appreciate it. (I should note that I misspoke…he’s a theoretical physicist). “Other interesting sessions I went to talked about sleep, narratives, the brain, the Turing Test, and why the difficulty of putting chiral fermions on a lattice is evidence against the idea that we live in a computer simulation. (That last one was from David Tong.)” http://blogs.discovermagazine.com/cosmicvariance/2011/08/17/data-fatigue/
Thanks – there is a similar paper listed in the comments, along with a lot of discussion about the topic (http://fqxi.org/data/essay-contest-files/Tong_integers.pdf).
Essentially, the argument he uses is what I got to with my caveat in the above post: The universe, to be properly simulated, he argues requires quantum mechanics (a topic over my head), by our current understanding. Digital computers cannot do this. He uses the example of the failure to representing chiral fermions on a lattice model…also over my head, but apparently a “chiral fermion” is not able to be represented discretely, which is the point of a lattice model.
Why this is, is essential to what a computer is, the way we understand it. If you’re familiar with Alan Turing, (he is discussed in many philosophy courses, although a computer scientist), you know of the Turing Machine. The Turing Machine is an extremely simple simulation of a digital computer. Anything a Turing Machine can calculate, a digital computer can, and vice versa.
(As an aside, the Turing Test you mentioned is simply a person sits down at a computer and types to someone using it. A computer artificial intelligence that can fool the user into thinking that there is another person at another terminal writing back to them passes the Turing Test [not done last I checked!]).
Turing Machines have an infinite memory but a finite number of discrete states, and a finite set of instructions on how to handle these states. Digital computers work the same way. The state is stored using binary representation, and the program is as well. In binary, the language of the modern digital computer, the number one:
0001
is discretely different than the number 2, or 3:
0010, 0011
There is no sort-of-one, there is no 73% chance of one like quantum mechanics seems to require. In fact, you can’t even represent all “real” numbers in binary. Any digital representation of a decimal or fraction can only go out to a pre-defined precision, since a digital computer only has a finite number of discrete states.
Therefore, by arguing, as that paper does, that integers, that is, discrete numbers, are not a primary building block but an emergent property of quantum theory, he argues computers can’t possibly simulate the universe. If the universe is non-deterministic, than a being placed in a deterministic simulation should see problems of some sort.
To my earlier point, if the brain works off of quantum mechanics, it cannot be simulated by what we think of as a computer, either. If it can’t be simulated by a digital computer, it can’t be considered deterministic. If it is truly non deterministic, there is free will.
The Wikipedia article on the Halting Problem (Turing-related as well) also discusses a class of problems a computer cannot solve (“decide”), based on logical contradictions (http://en.wikipedia.org/wiki/The_halting_problem). It touches on asking if any physical phenomena are non-computable by a Turing Machine. Similarly, it wonders if the human mind can always decide on the Halting Problem. Obviously, the above article argues the former question is “yes”, proving the world cannot be computer-simulated, whereas the answer to the second question would prove the human mind cannot be simulated as well…without worrying about quantum physics.
I guess the tl;dr of that is that digital computers can only represent discrete quantities.
In the 1980s, we had eight-bit color, which is enough information for 256 discrete colors. Then we got 16 bit color, which is 32k colors. Then 24, which I believe is 16 million colors. At what point can a human being stop seeing a difference? It’s about there because I’m not even sure 32 bit color, or four-billion shade color, exits. Same with CDs. Yes, you can’t represent *every* possible sound with digital music, but you can represent more discrete sounds than a person can actually hear.
The article argues that there are fundamental forces in the universe that exist in a continuous, or analog, world and therefore can’t be simulated. Add in the Schrödinger’s cat uncertainties… I’d argue, maybe we just don’t have enough bits to represent the discrete values we’d need, or the science to know what those states are.
But that’s why I’m in computers, and he’s in theoretical physics.
Sometimes I agree with Mark Twain, “Faith is believin’ in what you know ain’t so.”
Other times I think Hamlet had something: “There are more things in heaven and earth than are dreamt of in your philosoohy, Horatio.”