The episode started out by talking at length about how dogs evolved from wolves. Tyson tells us, “The awesome power of evolution transformed the ravenous wolf into the faithful shepherd who protects the herd and drives the wolf away.” But this was not actually an example of natural evolution, because it was produced by intentional human intervention, presumably after humans took wolf cubs and started raising them as pets. This example of artificial selection (not natural selection) is therefore an odd thing to be citing as something showing “the awesome power of evolution.”
Tyson then states the following:
If artificial selection can work such profound changes in only 10,000 or 15,000 years, what can natural selection do operating over billions of years? The answer is all the beauty and diversity of life.
This statement commits a logic error. It would be logically correct to make a statement like this:
If wind erosion can produce a 1% deformation in something in 10 years, how much of a deformation might wind erosion produce in 500 years? Easily 20% or more.
But by asking us to draw a conclusion about the power of natural selection (something blind) from the power of artificial selection (something guided), Tyson has committed a logic error as bad as in the statement below:
If non-blind painters can produce 100 portrait masterpieces in 200 years, how many portrait masterpieces might blind painters have produced in 500 years? Easily hundreds.
To the contrary of what Tyson claims, there is a very strong reason why we cannot explain any complex biological innovations merely by saying they were the result of natural selection. The reason is that natural selection never occurs in regard to some complex biological innovation until after it has appeared. Once a new biological innovation occurs, it may result in an increased reproduction rate or increased survival rate in the organisms with that biological innovation. But such a thing (a natural selection effect) never occurs in regard to some biological innovation until after that biological innovation appears. So natural selection can never be the cause of a very complex biological innovation. You don't explain something by referring to something that occurred after that thing appeared.
Tyson then makes some claims about DNA. He states the following:
DNA is a molecule shaped like a long twisted ladder or double helix. The rungs of the ladder are made of four different kinds of smaller molecules. These are the letters of the genetic alphabet. Particular arrangements of those letters spell out the instructions for all living things, telling them how to grow, move, digest, sense the environment, heal, reproduce.
This is a very big misstatement. Our DNA does not tell a fertilized ovum how to grow to become a baby, does not tell us how to move, does not tell us how to sense the environment, and does not tell us how to reproduce. It is not even metaphorically correct to make the statement quoted above, because DNA does not contain a human body specification. There is no layout or specification of a human bone structure or human limbs in DNA, nor is there any layout of the human eye or ears, nor is there any layout or specification of the human reproduction system. DNA is neither a blueprint nor a recipe for making a human (see the end of this post for quotes by several scientists clarifying that DNA is no such thing). DNA does not contain any instructions telling a fertilized egg how to progress to become a human baby.
How do we know that DNA has no such things? The first reason is that no such blueprint or recipe has been found in human DNA, even though it has been exhaustively analyzed by major multi-year science projects such as the Human Genome Project and the ENCODE project. The second reason is that the expressive limitations of DNA prevent it from ever expressing such complex information. Tyson refers to “the letters of the genetic alphabet.” The way that this alphabet works is that the only things that can be spelled out in such a language are amino acids. Below we see the genetic code used by DNA. The U, C, A and G in the table are the “four letters of the genetic alphabet” Tyson referred to. But as the table makes clear, the only things that can be spelled out with this genetic alphabet are amino acids (such as proline and valine) that are the ingredients of proteins.
DNA is therefore merely a repository of chemical information. It is not some blueprint or recipe for making a human, and its structural limitations prevent it from being such a thing. Consider a traffic light. A traffic light is an information system capable of presenting only three items of information: the messages “STOP,” “GO,” and “CAUTION.” Just as the physical limitations of a traffic light greatly limit the type of information it can present, the physical limitations of DNA greatly limit the type of information it can present, limiting such information to be only chemical information rather than complex structural biological information. The shapes and structures of complex three-dimensional organs and organ systems cannot possibly be expressed in DNA given the limitations of the genetic code, nor can complex assembly instructions such as would be needed to specify how to create a human body.
A third reason why Tyson cannot be correct in saying that DNA is something that contains “the instructions for all living things, telling them how to grow, move, digest, sense the environment, heal, reproduce” is that if DNA were to contain such information, which would be fantastically complex instructions, there would be nothing in a human womb capable of understanding instructions so complex. A blueprint dumped at a construction site (containing lumber, nails, bricks, mortar, copper wire and pipes) doesn't cause a building to be built. The building is only built because there are agents smart enough to read and understand the blueprint and act on its instructions. But we know of nothing at all in a human womb that would be capable of reading and understanding incredibly complex instructions for making a human if they were in DNA. Wombs don't have brains or minds.
So how is it that humans are able to reproduce? How is that a fertilized ovum is able to progress to become a full-sized baby? That is a gigantic mystery of biological life that we don't understand. The reality that DNA does not specify body plans or a recipe for making an organism is a fact that contradicts and smashes all attempts to explain a progression of earthly life forms merely by citing a progression of genomes, which is exactly the faulty explanation that Tyson relies on.
Tyson next tries to warm us up to the idea that random mutations (random changes in DNA) can produce changes in organisms. He first presents the very unimpressive case of a mutation that might have caused a bear with dark fur to become a bear with white fur, giving a camouflage advantage if the bear lived in a snowy climate. Strangely, the 2014 episode I am discussing was written two years after the New York Times reported “Polar bears...are not descended from brown bears, scientists report.”
But regardless of whether it did occur, a possibility such as the one Tyson has mentioned is not terribly improbable. Such a thing is called microevolution, a small change in an organism that does not involve any complex innovation. Microevolution does indeed sometimes occur.
You can get a rough idea of the likelihood of a favorable random mutation by considering the case of a monkey at a keyboard. If you are an average typist with about a 1% typing error rate, and you bring in a monkey to randomly strike a key on your keyboard, the chance of that random keystroke improving your text is about this 1% figure multiplied by the number of keys on the keyboard. This gives a probability of about 1 in 3000. Similarly, a random mutation in DNA might have something like 1 chance in 3000 of producing some tiny improvement that natural selection might favor.
But what's the chance of getting a new functional protein from random mutations? The chance of this is exponentially smaller. An average protein consists of about 200 amino acids arranged in just the right way to achieve a particular functional effect. There are 20 amino acids in the genetic code. A protein with 200 amino acids might have its amino acids arranged in 20 to the 200th power ways (20200 ways), and only a microscopic fraction of these would be functional. Similarly, there are roughly 30 to the 200th power ways in which a typing monkey might type random text (30200 ways), and only a microscopic fraction of these would be meaningful useful instructions.
So while it is not terribly improbable that a typing monkey might produce a keystroke that improves your written text (such a thing having a probability of about 1 in 3000), it is almost infinitely more improbable (more than a trillion quadrillion quintillion times more improbable) that a typing monkey might produce a usable 200-word computer program. And similarly, while it is not all that improbable that a single mutation might produce some small improvement in a genome, it is almost infinitely more improbable (more than a trillion quadrillion quintillion times more improbable) that random mutations might conspire to produce a protein of 200 amino acids arranged in just the right way to produce some novel functional effect. Given a billion typing monkeys across the globe hitting typewriter keys for a billion years, we would not expect any of them to produce a functional 200-word computer program; and given five billion years of random mutations across the globe, we would not expect a functionally useful new protein of 200 amino acids to appear by such chance mutations. The human genome contains genes for about 20,000 such proteins.
In the Cosmos episode, Tyson tells us a story about the appearance of a functional protein. Here is what he says:
In the beginning, life was blind. This is what our world looked like four billion years ago, before there were any eyes to see. Until a few hundred million years passed, and then, one day, there was a microscopic copying error in the DNA of a bacterium. This random mutation gave that microbe a protein molecule that absorbed sunlight.
Of course, this is utter nonsense. A random mutation changes exactly one nucleotide base pair in DNA, and its effect is never greater than changing or adding one particular amino acid in a protein. But proteins are made of hundreds of amino acids arranged in just the right way to achieve a functional effect. If a light-absorbing protein molecule had appeared by random mutations, this would have required a fantastically improbable conspiracy of random mutations occurring over millions of years. But Tyson has told us that “one day” such a functional molecule has appeared, because of a single random mutation. This is as crazy as someone saying that a monkey could produce a 200-character functional new computer program by typing a single keystroke (or an intelligible 50-word recipe by typing a single keystroke).
The molecular complexity of proteins was unknown to Darwin, who also knew nothing of the complexity of the cell. Proteins are a great embarrassment to all who would claim that humans are the result of blind forces. Our bodies are built of many thousands of proteins, but scientists have no credible accounts for the origin of any protein, and each is as complex a piece of functionality as a 200-word computer program. A mainstream scientific paper says, "A wide variety of protein structures exist in nature, however the evolutionary origins of this panoply of proteins remain unknown."
Tyson then tells us the following tale:
Here's a flatworm's-eye view of the world. This multi-celled organism evolved a dimple in the pigment spot. The bowl-shaped depression allowed the animal to distinguish light from shadow to crudely make out objects in its vicinity, including those to eat and those that might eat it a tremendous advantage. Later, things became a little clearer. The dimple deepened and evolved into a socket with a small opening. Over thousands of generations, natural selection was slowly sculpting the eye.
Tyson is using here a standard strategy for those trying to suggest that vision systems could have appeared accidentally: start out by mentioning the tiniest visual structure you can imagine, and hope that people regard this as something very simple that could have easily appeared accidentally. But if you were to delve into all the microscopic details and biochemistry details, you would find that this tiny thing is actually extremely complex. Cells are very tiny, but they have functional complexity so great they have been compared to small cities. There are 1000-page books devoted to nothing but describing the complexity of cells. And the flatworm organ Tyson refers us to is much more complicated than a cell.
Flatworms have primitive light-sensing structures called ocelli. In the quote above Tyson implies that first we had the fairly primitive ocelli of the flatworm, and then much later we had the first real eyes. This does not match what the fossil record tells us. Animals with the primitive ocelli of the flatworm do not appear earlier in the fossil record than animals with complex eyes. Both the flatworms and many types of animals with eyes are believed to have first appeared at the time of the Cambrian Explosion in which most of the animal phyla rather suddenly appeared, contrary to what we would expect from Darwinian gradualism. There is no fossil record of any primitive eyes that appeared before the first complex eyes in the fossil record, and which are believed to be the predecessors of species with complex eyes.
The visual above (from this mainstream science web site) shows the situation. The flatworms are the Platyhelminthes. Fish with eyes appeared in the phylum Chordata, the same phylum of humans. There is no evidence of fish descending from flatworms, and no evidence that the first animals with good eyes descended from flatworms (contrary to what Tyson has insinuated).
A very important misstatement by Tyson is his claim that the crude visual organ of the flatworm had the ability to “distinguish light from shadow to crudely make out objects in its vicinity, including those to eat and those that might eat it.” This amounts to a claim that flatworms have vision. But they have no such thing. They merely have a light-sensitive patch sufficient only to tell lightness from darkness. The primitive “eyes” of a flatworm (its ocelli) are not sufficient for it to “crudely make out objects in its vicinity.” And the tiny “brain” of a flatworm (with only a very small number of neurons) is way too small for vision. A scientific paper says this of the flatworm's-eye: “There is no image-forming apparatus, and the eye is probably used merely as a detector of light with directional sensitivity.”
What difference does it make whether a light-sensitive patch of an organism is sufficient to provide a crude, blurry form of vision, rather than merely telling an animal which direction is up and down? It makes a very great difference to the question of whether we can reasonably imagine a gradual evolution of an eye from a primitive light-sensitive patch. If a light-sensitive patch and the tiniest brain (like a flatworm has) is sufficient to produce crude vision, then we can imagine that each additional change leading up to an eye producing clear vision was a change producing a benefit to the organism that had such a change. If, on the other hand, a light-sensitive patch and the tiniest brain is not sufficient to produce vision, then we have to imagine many additional changes in the eye region and brain occurring without producing any reward, until finally after many required changes there occurred the late reward of functional vision. The latter scenario is one that is not credible under Darwinian assumptions.
There is no reason why natural selection would make a whole bunch of changes to produce a vision system unless there was a continual reward for each change in such a series of changes. But it very frequently happens (inside of biology and outside of it) that there is no continually rewarded path leading to a new complex innovation, and no reward comes until many changes are made, and many parts are arranged in just the right way. Such “late reward” scenarios are far more common than “continual reward” scenarios, a fact that constantly stymies and short-circuits explanations of the type Tyson is trying to make here. On the protein level, the origin of every functional protein is a “late reward” scenario (halves of a protein molecule being non-functional), so in the human genome with genes for some 20,000 proteins, we have some 20,000 “late reward” scenarios that all defy attempts to explain them by imagining some continually rewarded Darwinian path.
What Tyson has done is to paint a speculative picture of continually rewarded evolution from a primitive light-sensitive patch (supposedly producing crude vision) to an eye. The scenario is not supported by the fossil record, and is not credible because light-sensitive patches on organisms like flatworms do not at all produce crude vision. And when we delve down to the protein level, we find that even this supposedly primitive light-sensitive patch would require a very high state of functional amino acid organization most unlikely to ever appear by chance.
Based on these numerous misstatements and misleading impressions, Tyson claims, “The complexity of the human eye poses no challenge to evolution by natural selection.” To the contrary, there is no complex biological innovation that can plausibly be explained by natural selection, which never occurs in regard to a biological innovation until after that innovation occurs. Tyson has reached his reassuring “we got this” conclusion by engaging in various cheats large and small, including the gigantic whopper of claiming that a light sensitive protein might originate on a single day, the crucial misstatement suggesting DNA is a recipe for making an organism, the unfounded suggestion that the first advanced eyes evolved from primitive eyes (which the fossil record does not support), and the erroneous idea that mere light-sensitive patches like those in flatworms produce a crude form of vision. Once we realize that genotypes do not specify phenotypes (merely influencing them), and that DNA does not and cannot store body plans, the legs are pulled from out of the Darwinist explanation for complex biological innovations such as eyes. Since DNA does not actually store the extremely complex structural arrangement of a vision system, there is no way that vision systems could have appeared through any imaginable modification of DNA, whether it be random mutations or anything else.
Near the end of the Cosmos episode, Tyson claims that scientists are “not afraid to admit what we don't know.” To the contrary, many of them seem to not at all know what they do not know, and to think that they know very much more than they do know. The typical modern scientist claims that he understands the origin of complex visible biological innovations, but admits that he does not understand the origin of life itself or the mysteries of morphogenesis and embryonic development. It makes no sense to claim that you understand the first of these things without understanding the last two of these things, since there is every reason to suspect that all three are produced by similar causal factors. Man's knowledge of nature is fragmentary, and the mere fragments we have (like ten or twenty pieces of a 400-piece jigsaw puzzle) are not sufficient to allow us to answer biological origins mysteries that may take mankind a thousand years to unravel. It's no sin for a scientist to act like some “Wheel of Fortune” very-early-guesser who guesses the answer after only three or four of the 30 letters have been turned; but such guesses should not be passed off as established truth.
Tyson is one of many scientists who feed us similar origins baloney. Very recently the Science Daily web site (using a Stanford University press release) had a news article entitled, “Why deep oceans gave life to the first big, complex organisms.” The article dealt with the great mystery of why most of the known animal phyla suddenly appeared in the Cambrian Explosion, in a vast explosion of organization and functional information that included the first animals with vision systems. We are told in the last paragraph of the article that the explanation offered by an assistant professor Sperling is simply that the temperature at the bottom of the ocean was right for this. Sperling says, “The only place where temperatures were consistent was in the deep ocean. That's why animals appeared there.” This is reasoning on the same inane level as trying to explain the appearance of ten extraterrestrial monsters in your local swimming pool on Labor Day by saying that the reason the ten monsters suddenly appeared was that the water wasn't too hot or cold on Labor Day.
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