Are there brute facts?

The argument from contingency depends on the principle of sufficient reason (PSR). The PSR states that for anything that exists, there is a sufficient explanation for why it exists rather than not existing. The explanation can take one of two forms--either the explanation is that it exists by necessity (i.e. it's impossible for it to not exist), or it is contingent. If it's contingent, then the explanation will be found in something else that exists and which serves as the basis for, reason for, or cause of the existence of the contingent thing under consideration.

But then there are brute facts. A brute fact is something that happens to be so, and there's no reason or explanation for it. If there are contingent things whose existence are brute facts, then the PSR is false because in that case there would be contingent things for which there is no sufficient reason for their existence.

So what reason is there to think there either is or isn't any such thing as a brute fact? I'm not going to go into all the reasons, pro and con, in this post. I only want to address something I heard a few weeks ago. Ben Shapiro interviewed Ed Feser on his new book, Five Proofs of the Existence of God.

At around 7:40 in the interview, Shapiro brought up the subject of brute facts. Then at about 8:10, Feser began to respond to it. He said there were two problems with it. The first problem is that it's arbitrary and is brought up for no other reason than to avoid the existence of God. There's no independent motive or reason for suggesting brute facts. The second problem with brute facts (9:07) is that it eats away as all explanations in general because if all explanations ultimately rest on a foundation of brute facts, then that takes down the explanatory force of every other explanation. It's all just arbitrary.

While I can see the rhetorical force of Feser's two arguments, I don't think either one of them really undermines the existence of brute facts. The fact that a person might be motivated in an inappropriate way to postulate brute facts doesn't mean they're wrong. To say that they're wrong by pointing to their inappropriate motives is to commit the genetic fallacy. At best, I think this argument only tells us that there is no good justification for believing in brute facts. If there's no rational reason for them, and there are only pragmatic motives for suggesting them, then that does entail that brute facts are nothing more than unjustified hypotheses.

In the second argument, Feser uses an analogy to explain himself. There's a book on a shelf. The shelf is held by brackets. The brackets are held but other brackets. But those other braackets aren't attached anywhere. They're just brute facts. Well, if they're not attached to anything, then the shelf with the book will all fall down. It can't all be held up by brute facts. In the same way, all explanations collapse if they rest of a foundation of brute facts.

I don't think they collapse in the same sense that a book shelf collapses. All that would follow is that you can't give an ultimate explanation for anything. Ultimately, there's no reason for anything. What would Feser say to somebody who bit the bullet and said, "Okay, so there are no ultimate explanations. Everything is, by extension, a brute fact." It seems to me there's something missing in Feser's argument. He's attempting to make a reductio ad absurdum argument against brute facts, but he hasn't explained why the logical consequence of brute facts is absurd.

While I don't think what Feser said amounts to an argument against the existence of brute facts, I do think he successfully undermines rational belief in brute facts. It seems to me that it's unreasonable to postulate brute facts because of Feser's second argument, and brute facts do seem rationally unjustified because of Feser's first argument. That is unless there's some rational reason aside from motivations for brute facts that Feser didn't mention and that I'm unaware of.

Is the universe contingent?

Over the years I've had two reservations about the argument from contingency. The first reservation comes from the possibility that there are brute facts. The argument from contingency depends on the principle of sufficient reason which states that for anything that exists, there is a sufficient reason for why exists rather than not existing. If there are brute facts, then it could be that some things exists for no reason at all. They're just there, and that's all there is to it.

I am highly skeptical of brute facts, but I haven't been able to rule out the possibility completely. But supposing there are no brute facts, that brings me to the second reservation about the argument from contingency. Is the universe a contingent thing? It's hard to say.

If there is a necessary being, and the universe is it, then there would be no need to postulate anything beyond the universe to explain the existence of the universe. But if the universe is contingent, and there are no brute facts, then there must be something beyond the universe that explains the existence of the universe.

Ultimately, if there is anything at all that's contingent, then there must be something that exists by necessity. Ultimately everything contingent that exists must be traced back to something that exists by necessity. In other words, there must be something that exists, and it's impossible for it to not exist.

While I have no problem deducing the fact that there is at least one necessary being, I have a hard time wrapping my mind around anything actually being a necessary being. Whenever I mull over whether any given object is a necessary being, I do two things. First, I try to conceive of it not existing. Second, I try to see if there is any contradiction in the supposition that it doesn't exist.

Although I can see that there must be a necessary being of some sort, whenever I try to imagine such a being, it's just as easy for me to imagine it not existing. God, of course, is the being I think is necessary. But unless I stipulate from the get-go that God is necessary, there's nothing else in the concept of God other than the stipulation that prevents me from imagining his non-existence. So apparently, conceivability cannot help me answer the question of whether or not any given entity is a necessary being or not. The mere fact that I can imagine the universe or God not existing doesn't entail that either is a contingent thing.

But neither can I deduce a contradiction in the denial of the existence of the universe or God. It seems, at least prima facie, that there is a possible world in which God exists, but the universe does not. It also seems, at least prima facie, that there is a possible world in which the universe exists, but God does not. It even seems, prima facie, that there is a possible world in which nothing at all exists. The only way I can see to deduce a contradiction from the non-existence of any named entity or being is to add propositions to it that we have reason to think are true.

We can deduce that God is a necessary being by adding the proposition that God is the source of everything else that exists. If God is the source of everything else that exists, and everything must be traced back to some necessary being, then it seems to follow that God is the necessary being that everything is traced back to. Since the necessity of God would follow from these premises, then the denial of the existence of God would entail a contradiction.

Or, if we add the proposition that only the material world exists, and everything contingent can be traced back to a necessary entity, then it would follow either that the universe is a necessary entity or else some part of the universe is necessary. Since the necessity of the universe or some part of the universe would follow from these premises, then the denial of the existence of the universe would entail a contradiction. (Notice I didn't add "or some part of the universe." That's because if we deny the existence of the whole universe, then we would be denying the existence of every part of the universe as well.)

So what reason is there to think the universe might be contingent that wouldn't just as easily apply to God? Or what reason is there to think God is a necessary being that wouldn't just as easily apply to the universe? Even if we all agree that all contingent things have their origin in something that's non-contingent, we've got to figure out where we're going to halt our explanatory regress. And it can't be arbitrary. There's got to be a good reason for halting it where we halt it, whether we halt it with the universe or with something beyond the universe.

I've been thinking about that over the last two days, so I thought I'd share my thoughts with you. There are two things I have to say about it. First, I think it is plainly evident that anything composed of parts must be a contingent thing. The reason is because if something is composed of parts, then it can be disassembled. For example, my desk is composed of atoms. If those atoms were separated from each other and spread throughout the galaxy, then my desk would no longer exist.

However, it could be that while my desk, as a whole, is contingent, the individual parts that make up my desk might possibly be necessary. Ever since the pre-Socratic Greek philosophers, on down to modern day physicists, we have been trying to find out what the most fundamental thing in physical reality is. Many of the Greeks, like Lucretius and Democritus, said the most fundamental things are atoms. Fast forward a couple thousand years, and our physicists called the basic constituents of elements "atoms." But then we discovered that atoms are composed of protons, neutrons, and electrons. Then we discovered that protons and neutrons are composed of quarks. Now, some physicists think the most fundamental entities are tiny vibrating strings. Some think the most fundamental entities are quantum fields, like the electric field or the Higgs field. There's a field for every particle.

So while I can confidently say that atoms, stars, and people are contingent things, I've got to question whether or not the most fundamental thing (or things) that atoms, stars, and people are made of are also contingent things. If there is some fundamental, non-reducible, physical thing out of which all other physical things are composed, then whatever it is, it is not composed of divisible parts. It is simple in some sense.

That brings me to the second thing I had to say. Supposing the most fundamental things are strings or something yet undiscovered or even hypothesized, it would seem to be the case that there is some particular number of them. Maybe it's 10^500. Who knows? Whatever that number is, if we suppose these entities are non-contingent (i.e. they are necessary), it would follow that the number of them is also necessary. After all, if each one of them is necessary, then it's impossible for any one of them to not exist, and if it's impossible for any one of them to not exist, then there couldn't possibly be fewer of them. Also, if they are necessary, then there couldn't possibly be any more of them either. The reason is because there could only be more if more came into existence. But if something comes into existence, then there had to have been a state of affairs in which it didn't exist, in which case it couldn't have been a necessary thing. So if the fundamental particles, strings, or whatever of physical reality are necessary entities, then there is a fixed number of them, and whatever that number is, it is necessary that it be that number.

Doesn't that strike you as odd, though? That there would be some fixed number of strings, and that there couldn't possibly be one more or one less? While I can't prove it, I am inclined to think the number of fundamental particles/strings/whatever is not necessary. It is contingent. If it's even possible that there could be one more string or one less, then at least one of these strings is contingent. But if one is contingent, why think any of them at all would be necessary? How could we distinguish between contingent strings and non-contingent strings? If we suppose half of all strings are contingent, and the other half are non-contingent, then we're faced with the same issue. There would still be a fixed number of necessary strings.

So I have a hard time believing that any given number of things could be necessary. I have a much easier time believing that if something is necessary, then there's only one of its kind. It's easy for me to imagine that all contingent things have their origin in one necessary thing, but if you suppose that all contingent things have their origin in a multitude of things, say 5, 50, or 10^500, then I'd be left wondering why there has to be just that number and not one more or one less. I would be inclined to believe that the number is contingent, in which case we haven't traced everything back to something necessary yet. We would have to keep going until we traced everything back to one thing before I'd be satisfied.

It is hard for me to explain why I'd be satisfied with one necessary thing that is the source of everything else, but I'll try. We couldn't suppose that there was one less thing, because then there'd be nothing at all, and it wouldn't be the case that everything contingent is traced back to something non-contingent. Rather, everything would be contingent, and that doesn't even seem possible to me. But if we suppose there might two things rather than one, it's hard to see why "two" is a necessary number and why there couldn't be one more or one less. So one necessary thing is the only thing that really resonates with me. I don't know how to explain it any better than that.

If some physicist could show that the most fundamental physical reality is just quantum fields, and if that physicist could somehow show that there's only one quantum field (i.e. that the various fields we now suppose exist can somehow be unified), then I would be hard pressed to find any grounds to argue that the universe is a contingent thing. At that point, I'd probably be 50/50. I might wonder about the properties of the field, though, and whether those properties were necessary or contingent. It seems to me that for anything in motion, each state of that thing is contingent. But I don't think it would follow that the whole thing is contingent.

But supposing the universe is composed of irreducible strings or some other particles, then I would be strongly inclined to believe that the whole universe was contingent. And if the whole universe is contingent, then the explanation for the universe must be something beyond the universe. Now we're getting into God territory. Of course one can always suppose that the universe has it's origin in something else that is contingent, but even if so, that contingent thing would ultimately have to trace its origin to something non-contingent. You can't escape the existence of something non-contingent no matter how many contingent things you put before the universe. Whatever that thing is, and I'm strongly inclined to think it's just one thing for the reasons I've already given, it would have to be god-like. It would be a non-physical necessary being that is the origin of everything else that exists. I think we can attribute those properties at a minimum with a fair degree of certainty. We might be able to infer various other properties, but in that case I think we'd be on less firm ground and we'd be venturing into speculation.

So where do I stand on the argument from contingency? Well, I think the argument from contingency shows with a high degree of certainty that there is a necessary entity, probably just one, that is the source for everything else that exists. It falls short of certainty to the degree that brute facts are possible. This argument, by itself, doesn't show that YHWH exists, although the conclusion of this argument could be used as a premise in a larger argument for the existence of YHWH. For me, this argument could be strengthened if I had better reasons to think the universe is contingent. While I strongly suspect the universe is contingent, I don't really have a strong argument for it. Well, let me back up. I think Kalam-type arguments give us strong reasons to think the universe is contingent, but I'm trying to evaluate the argument from contingency as a stand-alone argument without invoking other theistic arguments to prop it up.

Melinda Penner

I just found out a few minutes ago that Melinda Penner at Stand to Reason had a bad accident a few days ago. She is still in bad shape, so if you're the praying sort, please remember her in your prayers. Thanks!

Cancer and cataracts

I saw this Ted talk recently where this guy was talking about taking white blood cells out, re-engineering them to kill cancer cells, then injecting them back in. They managed to completely cure a little girl of leukemia.

I googled around and found that this treatment is FDA approved, but only for treating leukemia. The reason is that it can't kill tumors. When it attacks the cells on the outside of the tumor and they all die, it creates a wall that the white cells can't get through, so they can't kill the rest of the tumor.

I also read that once you've had some of your white blood cells engineered and re-injected, it's for life. All of your white blood cells will forever be able to fight cancer. It seems to me that if that's true, then this technology ought to be able to be used as an inoculation against cancer. It may not be able to destroy a tumor, but it ought to be able to prevent a tumor from ever forming. I'll have to do more googling around about that. If this were FDA approved for inoculation against cancer, I'd be first in line!

In other news, I'm starting to get old man eyes, which makes it harder to focus on things close up. From what I read that happens to pretty much everybody because the lens in your eye hardens so that it can't change shape as easily. The solution is reading glasses, bi-focals, or interocular lens (IOL) implants. Lens implants are usually for people with cataracts, though.

I started reading around about lens implants and watching YouTube videos. Most implants will only allow you to focus on one distance, but now they have multi-focal lenses that allow you to see clearly both close up and far away. Insurance usually doesn't cover those, though.

There are all kinds of multi-focal lenses now. The coolest one I've seen anywhere is called FluidVision 20/20. It's a liquid IOL that works pretty much like your natural lens. Well, it does the same thing, but not exactly in the same way. Anyway, it supposedly allows you to see 20/20 at every distance. Check this out.

I seriously want that! It's not FDA approved yet, much less will insurance pay for it. I would gladly volunteer for a clinical trial, though. I've been wearing glasses since I was 20, and I've never gotten used to them. I only wear them when I drive. I hate hate hate wearing glasses! Wouldn't it be awesome to have 20/20 vision even when you're old without glasses or contacts? I can't even wear contacts. I tried two or three years ago, but neither I nor the doctors could get them in. I would pay oodles and doodles for FluidVision if I could.

Spirits and dark matter

I just now had a crazy thought. You see, Mormons think of spirits differently than most of us do. When most of us think of spirits, we think of beings that are immaterial and intangible. But to Mormons, spirit is a kind of matter. In LDS theology, there are two kinds of matter--ordinary matter that we're all accustomed to and spirit which is a more refined form of matter and which is invisible.

I don't know the details about the Mormon view. In Doctrine & Covenants 131:7-8 it says, "There is no such thing as immaterial matter. All spirit is matter, but it is more fine or pure, and can only be discerned by purer eyes. We cannot see it; but when our bodies are purified we shall see that it is all matter." I don't know if there's anything in Mormon scripture beyond that, so it may be that anything beyond that is speculation. I'd like to know what they mean by "fine or pure." What is impure about ordinary matter? I can't even imagine what kind of impurity might exist in atoms or subatomic particles.

But anyway, what just occurred to me is that maybe all this dark matter physicists have been telling us about is actually the Mormon spirit world! Supposedly, there is more dark matter in the universe than there is regular matter, but nobody knows exactly what it is. It's a mystery. It's invisible.

Mormons believe that Heavenly Father is a physical being who exists in this universe. It would stand to reason that the entire spiritual world would also exist as part of this universe. That means all of Heavenly Father's spiritual children exist in this universe. That includes all the angels and demons and everybody who has not yet been born into this world as well as those who have been born into this world but have died. It may also mean that every other god from every other world exists in this universe as well as their spiritual children, though I'm not sure about that. Mormons sometimes say that Heavenly Father is the god of this world, and maybe "this world" means this whole universe in which case other gods would probably be excluded.

Anyway, it's just a thought I had.

A time to. . .

I'm reading the Tao Teh Ching today, by Lao Tzu maybe. I got to chapter 29, and it said:

In fact, for all things there is a time for going ahead, and a time for following behind;
A time for slow-breathing and a time for fast-breathing;
A time to grow in strength and a time to decay;
A time to be up and a time to be down.

Does that sound familiar to you?

Review: The Blind Watchmaker by Richard Dawkins, part 2

There are a couple of places in this book where Dawkins addresses intelligent design. He addresses it on page 141 in the context of the origin of life, then again on page 316-317 in the context of evolution. He says basically the same thing he said in The God Delusion. Essentially, he raises the “Who designed the designer?” argument. Here is what he said:

So, cumulative selection can manufacture complexity while single-step selection cannot. But cumulative selection cannot work unless there is some minimal machinery of replication and replicator power, and the only machinery of replication that we know seems too complicated to have come into existence by means of anything less than many generations of cumulative selection! Some people see this as a fundamental flaw in the whole theory of the blind watchmaker. They see it as the ultimate proof that there must originally have been a designer, not a blind watchmaker but a far-sighted supernatural watchmaker. Maybe, it is argued, the Creator does not control the day-to-day succession of evolutionary events; maybe he did not frame the tiger and the lamb, maybe he did not make a tree, but he did set up the original machinery of replication and replicator power, the original machinery of DNA and protein that made cumulative selection, and hence all of evolution, possible.

This is a transparently feeble argument, indeed it is obviously self-defeating. Organized complexity is the thing we are having difficulty in explaining. Once we are allowed simply to postulate organized complexity, if only the organized complexity of the DNA/protein replicating engine, it is relatively easy to invoke it as a generator of yet more organized complexity. That, indeed, is what most of this book is about. But of course any God capable of intelligently designing something as complex as the DNA/protein replicating machine must have been at least as complex and organized as that machine itself. Far more so if we suppose him additionally capable of such advanced functions as listening to prayers and forgiving sins. To explain the origin of the DNA/protein machine by invoking a supernatural Designer is to explain precisely nothing, for it leaves unexplained the origin of the Designer. You have to say something like ‘God was always there’, and if you allow yourself that kind of lazy way out, you might as well just say ‘DNA was always there’, or ‘Life was always there’, and be done with it. (p. 141)

And again:

We cannot disprove beliefs like these, especially if it is assumed that God took care that his interventions always closely mimicked what would be expected from evolution by natural selection. All that we can say about such beliefs is, firstly, that they are superfluous and, secondly, that they assume the existence of the main thing we want to explain, namely organized complexity. The one thing that makes evolution such a neat theory is that it explains how organized complexity can arise out of primeval simplicity.

If we want to postulate a deity capable of engineering all the organized complexity in the world, either instantaneously or by guiding evolution, that deity must already have been vastly more complex in the first place. The creationist, whether a naïve Bible-thumper or an educated bishop, simply postulates an already existing being of prodigious intelligence and complexity. If we are going to allow ourselves the luxury of postulating organized complexity without offering an explanation, we might as well make a job of it and simply postulate the existence of life as we know it! In short, divine creation, whether instantaneous or in the form of guided evolution, joins the list of other theories we have considered in this chapter. All give some superficial appearance of being alternatives to Darwinism, whose merits might be tested by an appeal to evidence. All turn out, on closer inspection, not to be rivals of Darwinism at all. The theory of evolution by cumulative natural selection is the only theory we know of that is in principle capable of explaining the existence of organized complexity. Even if the evidence did not favour it, it would still be the best theory available! In fact the evidence does favour it. But that is another story. (p. 316-317)

I think Dawkins would have a point if what we were trying to explain was the origin of intelligence. To say that intelligence came about because some other intelligence created it is not to explain the origin of intelligence at all because it leaves the intelligent creator unexplained. As long as you’ve got an unexplained intelligence, you haven’t explained the origin of intelligence per se.

That appears to be a perfect parallel to what Dawkins is trying to argue except that instead of intelligence, he says we are trying to explain the origin of organized complexity. If we postulate an organized complex entity, like God, to explain organized complexity, then we haven’t really explained organized complexity at all since we’ve left God unexplained.

Dawkins’ argument commits the fallacy of equivocation. He says that for God to be able to design the DNA/protein replicating machine, God would have to be at least as complex and organized as the machine itself. Maybe one could argue that God would have to be complex and organized in some sense, but surely God would not have to be complex and organized in the same sense that the DNA/protein replicating machine is complex and organized.

Dawkins goes to great lengths on pages 6 through 9 to explain what he means by complexity. He says that a complex entity would have to be heterogeneous, meaning it “has many parts, these parts being of more than one kind.” Then he says the parts must be “arranged in a way that it is unlikely to have arisen by chance alone.” But since any arrangement of parts can be equally unlikely with hindsight, the arrangement must be something that can be “specified in advance.” What he appears to mean is that the parts must be arranged in such a way that the entity is “good for something,” or that it can “succeed in making a living of some sort,” such as “flying, swimming, swinging through the trees, and so on.” To summarize, Dawkins says:

This has been a long, drawn-out argument, and it is time to remind ourselves of how we got into it in the first place. We were looking for a precise way to express what we mean when we refer to something as complicated. We were trying to put a finger on what it is that humans and moles and earthworms and airliners and watches have in common with each other, but not with blancmange, or Mont Blanc, or the moon. The answer we have arrived at is that complicated things have some quality, specifiable in advance, that is highly unlikely to have been acquired by random chance alone. In the case of living things, the quality that is specified in advance is, in some sense, ‘proficiency’; either proficiency in a particular ability such as flying, as an aero-engineer might admire it; or proficiency in something more general, such as the ability to stave off death, or the ability to propagate genes in reproduction. (p. 9)

The reason I accuse Dawkins of equivocation is because God is obviously not complex in the same sense that biological organisms (or airliners and watches) are complex. God may be complex in the sense that he has various attributes and a creative mind, but he’s not complex in the sense that he has various physical parts that are arranged in an unlikely way that results in some function that allows him to make a living and reproduce. Clearly, when we say a biological organism, or an airplane, is complex, we don’t mean the same thing as we might mean if we said God is complex.

Consider one example of supposed intelligent design—information in DNA. Stephen Meyers argued in Signature in the Cell that information always comes from a mind, and since DNA contains information, that information came from a mind. That same argument could not apply to God since God wouldn’t have anything like DNA. He wouldn’t have anything like a digital code written into his parts that codes for proteins. So this intelligent design argument would be immune to Dawkins’ criticism. The best Dawkins could say in response to this argument is that an intelligent designer is unnecessary since information can arise without a designer, but he couldn’t claim that information in DNA hadn’t been explained since the intelligence behind it hadn’t been explained. That would be like saying that programmers don’t explain computer programs since it leaves programmers unexplained or that authors don’t explain books since it leaves authors unexplained.

Neither natural selection nor intelligent design are meant to explain the absolute origin of complexity in general. Both have a more narrow focus. They are trying to explain biological complexity in physical living organisms. In that case, it’s perfectly reasonable to explain complexity in biological organisms by postulating an entity that is not a biological organism, even if that entity is complex in some sense. If I appeal to one complex entity in order to explain another complex entity, I may not have explained the origin of complexity in general, but I have explained the origin of a particular manifestation of complexity.

The difference between God and biological organisms is particularly revealing in how Dawkins responds to the claim that “God was always there.” He says that if we’re going to allow ourselves the luxury of postulating an already existing complex entity like God, you might as well just say, “DNA was always there,” or “Life was always there.” But it is precisely because we already know DNA and biological life were not always there that gives rise to the need to explain them by postulating something that was always there.

As long as anything contingent exists, something necessary must exist. Each contingent thing is explained either by some other contingent thing or by some necessary thing. Necessary things do not require other things to explain them. They exist because they are necessary, and their necessity is a sufficient explanation for their existence. So always-existing things can be invoked to explain contingent things. All parties agree that DNA and protein are contingent things. It is because they are contingent things that we cannot simply postulate them the same way we can postulate an always-existing Designer. Once we trace all contingent things back to some necessary thing or things, our explanation is complete.

And now my review of The Blind Watchmaker is complete. I know I sound mostly negative in this second part, but I was only criticizing a small part of Dawkins’ book. The book as a whole is fantastic, and I recommend it. I would give it four and a half stars.

Review: The Blind Watchmaker by Richard Dawkins, part 1

I just finished reading The Blind Watchmaker by Richard Dawkins. Over all, I would say this is an excellent book. It wasn’t exactly what I expected, though. The subtitle reads, “Why the evidence of evolution reveals a universe without design.” I expected Dawkins to go into some detail about the hard evidence—fossils, geology, geography, genes, heredity, homology, etc. But really, most of the book was theoretical and speculative. For the most part, he showed how evolution could happen without showing that it did.

That’s not to say he didn’t discuss the hard evidence. He did. It just wasn’t the main focus of the book. Concerning the hard evidence, there was one part of the book I found to be especially compelling. It was chapter 10: “The one true tree of life.” More specifically, it was pages 270—276. And even more specifically, it was pages 274—275. I am probably going to butcher this explanation.

Okay, so there are a lot of genes in our DNA that code for proteins, and those same genes and proteins can be found in various species. However, there will be neutral differences, meaning there’ll be differences in the code that don’t affection the shape or function of the protein. That means they are invisible to natural selection. According to Dawkins, a given protein will change at the same rate regardless of what species that protein is found in. And, he says, we can know what that rate of change is, which allows us to know how long ago two species branched off from each other, i.e. how long ago their common ancestor lived. Unfortunately, Dawkins doesn’t tell us how we know about the mutation rate (unless it’s somewhere else in the book and I missed it).

Let’s suppose we have five different species, and we want to see how they are related to each other on a family tree. Well, we can look at the same protein in all five species, and by comparing them, we can tell how they are related to each other by how they differ. It’s a lot like textual criticism. You can tell that a text belongs to the Alexandrian text type or the Byzantine text type by looking at the differences of a given text. Supposedly, we can even tell how long ago each of them branched off from the others—the species, not the texts.

However, it’s always possible that a protein in two different species will change in the same way. It’s just a big coincidence when they do, and it apparently doesn’t happen very much. If it does happen, then looking at the one protein in each of the species will give you the wrong idea about how they are related and when their common ancestor lived.

But there’s a solution to that problem, and this is really the part that I found compelling. You don’t have to just rely on one protein to figure out a family tree. You can look at multiple proteins. The crazy thing is, when you look at multiple proteins, they will all tell the same story. You might get one that tells a slightly different story in case there was some huge coincidence in which the same protein in two different species mutated in exactly the same way. But that false reading can be recognized and corrected since every other protein tells the same story. It’s unlikely that one protein in two species would mutate in the same way, which is why we call it a coincidence, but it’s a whole lot more unlikely that two different proteins shared by two different species would both mutate in exactly the same way. These various proteins not only agree with each other in how the various species are related to each other, but they even agree on how long ago the different species branched off from each other.

I find this to be very compelling evidence for common ancestry. The fact that different species share the same protein, even if slightly modified, is flimsy evidence for a common ancestor. You could only arrive at that conclusion if you already assumed they had a common ancestor, and you were just trying to figure out how closely related they are. But if various species were not actually related by common ancestors, and you analyzed multiple proteins they had in common on the hypothesis that they were related, it seems highly unlikely to me that they would all give the same results. While you might dismiss one protein that points to a certain relationship, it’s hard to dismiss multiple proteins when they all give the same relationship and age of divergence.

It won’t do to say that a designer would, of course, use the same code in various species. Surely he would, but remember that we are talking about neutral differences in these proteins. They are differences that don’t affect the shape or function of the proteins. So there is no reason for them to be different on the hypothesis that a designer created them directly except that it doesn’t matter and they might as well be. But if it doesn’t matter, then we should expect the differences to be arbitrary, and if the differences are arbitrary, then we should not expect multiple proteins shared by different species to all agree on how those species would be related if they shared common ancestors.

That is not to say a designer is unlikely to have been involved. From what I understand, there are different theories in intelligent design about when, where, and how the designer got involved. Maybe he designed and assembled the first cell, and it took off from there. Maybe he interjects new information into DNA on rare occasions, like when he wants to add a brand new gene or disable one. Or maybe he manipulates the environment in such a way as to determine natural selection. All of those, it seems to me, would be consistent with the evidence I’ve been discussing. So a designer is not inconsistent with common descent. I only mean to say that Dawkins gave what seems to me to be a very compelling argument for common descent that suggests to me that each species was not a special creation that God made from scratch.

In part 2, I’ll talk about some problems I had with the book.