Probability of life

The Improbability of Probability

To understand probability, let us look at a few examples. The probability of a flipped coin coming up heads is 1 chance out of 2. What is the chance of three coins coming up heads? It is one out of 2 X 2 X 2 or eight. As we increase the number of coins flipped, the probability of getting all heads decreases rapidly. With ten coins, the probability is 1 in 1024. With 20 coins, it is 1 in 1,048,576.

The Left­ Handed Amino Acid Dilemma

Let us now apply the principles of probability to the problem of origin of life. Proteins are an important family of molecules that make up life. They are gigantic in comparison to ordinary chemicals found outside life. Typically, a protein is 400 to 1000 times larger and more complex than the molecules that make up gasoline. A protein is a polymer, which is a chain of components all linked together. We call these links in the chain amino acids.

If you chemically build amino acids in a test tube, they will form into equal amounts of "right handed" and "left handed" isomers. This concerns the three dimensional shape of the molecules. Chemically, the right handed and left handed forms react the same, and are indistinguishable apart from their three dimensional orientation. The two forms are mirror images of each other.

There are twenty different amino acids used as building blocks in proteins. The sequence of the amino acids and the three dimensional shape determine the function of the protein. Therefore, let us look at what it would take to create a functional protein or enzyme.

A typical protein is made up of a chain of 445 left-handed amino acids. No protein found in nature contains right handed amino acids. Though origin of life experiments produce equal mixtures of both, all proteins use only the left-handed variety. Therefore, in order for the original protein to be formed, all amino acids used out of the original mixture needed to be left-handed.

We can now apply the laws of probability to this. The chances of an average protein consisting of 445 amino acids forming by chance are one chance out of 2410 or 10123 (35 of the amino acids would be glycine, which is symmetrical).

To illustrate the magnitude of this impossibility, let's have a contest. Suppose we give a snail moving at the speed of one inch every million years the task of moving the entire earth atom by atom over to the other side of the universe and back.

Then, imagine the length of time it takes light to travel one millimeter, and a million proteins forming in that length of time hoping to form one protein with all left-handed amino acids. Guess what! The snail would win, many millions of times over before even one left-handed protein would be formed!

Presume now that we can make amino acids ambidextrous for the moment and ignore this problem for the evolutionists' sake. We now have a problem making sure that the amino acids are in the right order to give the protein its function. Each amino acid has a characteristic that forms weak bonds, giving the protein its three dimensional shape. It is this shape that gives the protein its activity in living systems.

If we disturb a protein with an outside force such as heat, acid, or any other abnormal environment, the three-dimensional shape of the protein will be upset, and it will lose its activity. When this happens, we say the protein is denatured. Therefore, a protein may have all its amino acids left-handed and in proper sequence and still be useless because the three dimensional shape is not correct.

There are twenty amino acids that make up the basic building blocks of the protein. The order is very important, like the code of a computer program, or a sentence in a book. If just one amino acid is out of sequence, it changes the entire structure of the protein, just like changing a word in a sentence.

This is the effect of a mutation. It weakens the protein's function, usually to the point where it no longer does its job. The origin of disease is simple, it is a departure from the perfect creation of God caused by mutations. Mutations are a degenerative process and not the driving force evolutionists seek to explain the origin of life.

Let us assume in spite of the incredible odds that we now have a protein meeting every requirement, with left-handed amino acids, proper amino acid sequence and three dimensional structure. The next problem to face is configuring the least number of proteins, needed with DNA and associated molecules to form a living cell.

Scientists estimate that 238 proteins would be the absolute minimum number that would be needed to form life. Is it possible to bring together that many proteins and interrelate them in such a way to continuously process food and energy? A problem in doing this is even if we concentrated the right proteins together in the same place at once, they still would have to be configured in the proper structure in order for life to exist.

Coppedge, in his book, Evolution: Possible or Impossible, makes several probability calculations concerning life coming about by chance. Giving evolution all kinds of concessions, he comes up with the probability for the first cell to evolve by accident as one chance in 1029345. It would take an 80-page book just to print that number. In comparison, the number of inches across the known universe is 1028. Statistically, scientists consider 1 chance in 1050 to be impossible. From these figures, you can be certain that the evolution of the cell is impossible!

Some have thought that viruses are precursors to living cells, but to reproduce, viruses need living cells as hosts! So even if a virus happened to appear by chance, it would have been the last unless there was a cell nearby whose reproductive mechanism it could exploit.

http://www.rae.org/revev6.html

Originally posted by dj2becker
The Improbability of Probability

To understand probability, let us look at a few examples. The probability of a flipped coin coming up heads is 1 chance out of 2. What is the chance of three coins coming up heads? It is one out of 2 X 2 X 2 or eight. As we increase the number of coins flipped, the probability of getting all heads decreases rapidly. Wit ...[text shortened]... s a cell nearby whose reproductive mechanism it could exploit.

http://www.rae.org/revev6.html

This post sounds pretty ridiculous due to the fact that the author failed to write the exponential expressions correctly (they were most likely lost in the cut-and-paste job).

Recently, creationists have taken up a new tactic, referred to as the "Intelligent Designer" or "Sudden Appearence" argument. The complex molecules of life, including DNA, are, they say, "too complicated" and "too improbable" to have arisen on their own through random chance, and therefore they must have been deliberately strung together by an "intelligent designer" with supernatural powers. Some creationists illustrate their claim by pointing out that the odds of an intact strand of DNA forming all at once from chance are the same as the odds of a tornado sweeping through a junkyard and assembling a functional Boeing 747.

There are a number of things wrong with the creationist "probability" argument, however. The first and most obvious is that wildly improbable things happen all the time. How improbable must a thing be before it is "too improbable" to have happened without Divine Influence? The odds of any human being being struck by lightning are enormously improbable, yet every year at least a dozen people are killed in the United States by lightning bolts. Have they all been struck down by God? Is the chance of any particular person being struck by lightning "too improbable" to have happened by chance?

Continued...

Another example: in an ordinary deck of playing cards there are 52 cards. If I deal these out face up, the odds of that particular combination arising in order, by chance, are 52-factorial; that is, 52 x 51 x 50 . . . x 3 x 2. That is one heck of a big number, and the odds are astronomically against dealing that particular hand at that particular time. Yet there it will be, staring us right in the face. If I were to take ten decks of cards and deal them all out, face up, the odds against that particular combination arising by chance are higher than the number of electrons in the universe. Yet again, there it will be. Is it therefore impossible for that particular combination to have arisen by chance? Is the appearence of this particular combination "too improbable" to have happened by chance? Do I witness a Divine Miracle every time I deal out ten decks of playing cards? I very much doubt it.

Even more fatal to the creationist "probability" argument, however, is the simple fact that the odds they are talking about are irrelevant, since neither biomolecules nor living cells are formed "randomly" or "by chance". Life is a chemical process, and like all chemical processes it is governed by the deterministic laws of chemistry and physics. These laws are not "random".

Continued...

If we have a number of amino acids in solution, for instance, they do not combine "randomly"---they combine according to their chemical properties. Thus, any given mixture of amino acids will always combine in the same ways, in accordance with the laws of chemistry. The idea that there are an astronomical number of possible combinations is simply wrong. The laws of physics narrow the possible chemical combinations to a very much smaller number --the possible number of electron configurations in the outer shell of those atoms. All of the other "possible" combinations are forbidden by the laws of chemistry and physics.

Thus, in their "probability" argument, the creationists conveniently neglect to mention that the combination of the components of those biomolecules is not "random"--they are precisely determined by the iron laws of chemistry and nuclear physics. Put a group of amino acids in proximity and they will combine in the same basic ways every single time, due to the chemistry of carbon atoms. This makes the "probability" that a collection of amino acids will combine to form a particular protein very near 100%. The laws of chemistry and physics drastically reduce the number of "possible" chemical combinations--and in many cases leave only one possible chemically stable configuration.

Continued...

The creationist contention that a cell or a strand of DNA arose "all at once" is a straw man. No one has ever suggested that an entire living cell or biomolecule "poofed" into being all at once, intact. Instead, the appearence of the first replicating molecule (as well as the first living cell) was a steady process of step-by-step building, beginning with a proteinoid and adding bits and pieces from there. No evolutionary biologist has ever asserted that biomolecules or living cells must have arisen all at once, in complete and final form. Since a whole series of intermediate chemical steps preceed their formation, the creationist argument that intact biomolecules could not have arisen by chance is completely irrelevant.

Closely tied with the creationist "probability" argument, however, is the assertion that an "intelligent designer" must have directed this process. The most widely-known proponent of this view has been Michael Behe, a Roman Catholic who, unlike most creationists, accepts that life evolved over billions of years and also accepts that humans are evolved from apelike primates, but who thinks that God (uh, I mean "an Unknown Intelligent Designer"😉 intervenes at scertain points to manipulate the evolutionary process. In his book Darwin's Black Box, Behe uses something he calls "irreducible complexity" to illustrate this intervention. "Irreducible complexity" means, according to Behe, that there are systems in the natural world that are made up of a number of interdependent parts, and these systems are so interdependent that they cannot function without the simultaneous presence of all the components. They are "irreducibly complex", and can exist only as a total collection or not at all. As he puts it: "By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional." (Behe, p. 39)

Continued...

Since the odds that all of these necessary components would have evolved all at once, intact and functional, at the same time are too improbable, and since it is impossible for them to have arisen step by step, Behe concludes, they must have been deliberately placed together by an "intelligent designer". Behe cites a number of biological processes, including the human immune system and blood clotting, which, he says, are "irreducibly complex" and must be the product of an "intelligent designer".

Behe's argument is not really new-it is merely a restatement of an argument made over a hundred years ago by the British clergyman Paley. Paley argued that if we find a watch lying on the grass, we must conclude, from the perfection and intricacy of its structure and function, that it was deliberately constructed by a designer. In the same way, Paley argued, when we look at the intricacy and perfection of the biological world, we must conclude that it, like the watch, is also the product of a designer-the supernatural designer we call God. Paley's thesis has become known as the "argument from design".

Continued...

The problem with both "irreducible complexity" and the "argument from design" is that neither has anything scientific to say, and both are based solely on religious assumptions. A scientific proposition of the form "life was designed by an intelligent designer" must be capable of being tested and potentially falsified. But how can we do this? How do we differentiate a "designed" organism from an "un-designed" one? What sort of evidence, in principle, would indicate that a "designer" exists, and what sort of evidence would, in principle, argue against the existence of a "designer"? What sort of objective test allows us to distinguish that something was designed (other than simply looking at it and concluding "it sure looks designed to me". . . ) ?

Behe's entire argument is best viewed as a version of the "argument from ignorance". In essence, his entire argument boils down to "I can't see how this process could have evolved step-by-step, therefore it could not have." The fact that Behe (or anyone else) cannot determine how a process evolved step-by-step does not constitute evidence that it did not, however. In fact, in several of the cases that Behe cites as "irreducibly complex", new discoveries in biochemistry have indeed led to descriptions of precisely the sort of step-by-step development that Behe claimed was impossible.

Continued...

In his work, Behe ignores a very important concept of biological evolution, the idea of "exaptation". This occurs when a biological trait is modified for use in a completely different system, and takes up a new function that it did not have before. Exaptations explain many of the "complex systems" we see in living things.

We can illustrate this with Behe's own example. Behe cites a mousetrap as an illustration of an "irreducibly complex system", and argues that since each component of the mousetrap--the spring, the wooden base, the wire hammer--is necessary for the functioning of the mousetrap, no functional trap can have developed step by step, without all of these things being present. Let us, then, show how a mousetrap could indeed evolve step by step, using exaptation.

We begin with the simplest possible "mousetrap"--a simple piece of bait left out on the floor. When the mouse approaches the bait, we hit it with a hammer.

A slight modification to our existing system. We place the bait in a small hole or hollow in the wall. This has the advantage of momentarily confusing the mouse when we surprise it at the bait, since it takes a moment for the mouse to find the exit hole, giving us more time to hit it with the hammer.

Continued...

Another slight modification--we place a small metal hinged door over the opening to the hole, which swings freely back and forth. This confuses the mouse slightly more and it takes a little bit more time to find the exit -- giving us a bit more time to hit it with the hammer.

Next, we add a spring mechanism that can be tripped by the mouse as it takes the bait, thus causing the door to close behind it. The advantage is that we no longer have to be waiting there when the mouse enters--instead, the mouse is now confined and can be hit with us by a hammer at any convenient later time.

Another modification: we turn the whole apparatus 90 degrees so it rests horizontally instead of vertically. In other words, our baited hole is now in the floor instead of in the wall. This has the advantage of allowing the mouse to approach our trap from any direction, instead of limiting access to just one side of the wall.

Another modification: We eliminate the hole and simply place the spring door apparatus on the floor in such a way that, when tripped, the trap door slams down forcefully on the floor where the trigger is located, mashing the mouse for us when it trips the trigger. The new advantage is that we no longer have to hit the mouse with the hammer at all--the new trap in effect does that for us.

Continued...

A final modification. We cut out the part of the floor that surrounds our trap and attach the trap mechanism directly to it. This allows us to deploy our trap anywhere we like, instead of limiting it to one locality.

And there we have it---step by step development of something that is supposed to be "irreducibly complex". Each step is fully functional by itself, and in each step, the intended result is achieved--a dead mouse. Each successive step builds upon the preceding one by small modifications, yet each step is more efficient in some way than its predecessor. And each step uses "exaptation"---it coopts whatever happens to be handy and incorporates it into our growing system. The bait used in the first trap can be a leftover from last night's dinner, or it could be a crumb we find behind the couch. The wall can be anywhere in the house. The free-swinging trapdoor could come from an old Coke machine, or it could be taken from the ice cube maker on the fridge. The spring can come from any bit of machinery we have around the house.

Evolution is full of examples of such exaptation, in which previously unrelated structures are incorporated into developing systems and given new functions. One example is the development of feathers for insulation in small theropod dinosaurs--feathers which were later incorporated into wings as flying mechanisms. A particularly good example of exaptation is the therapsid-mammal fossil series (discussed in another article) which shows the gradual changes that resulted from exapting the reptilian lower jawbones to work as inner ear bones instead.

Continued...

By claiming such systems to be "irreducibly complex", Behe is demonstrating a basic ignorance of how evolution works.

In effect, Behe's "designer" is nothing more than the old "God of the gaps", in which anything we do not yet understand is attributed to divine action. The problem with this viewpoint is that, as we understand more and more, there is continually less and less for the God of the gaps (or Behe's "designer"😉 to do.

In addition, neither Behe nor anyone else can scientifically say to us anything about their "intelligent designer". What exactly is the scientific theory of intelligent design? According to this scientific theory of intelligent design, what is the intelligent designer? Is it a space alien? A god or goddess? The Great Pumpkin? Time-traveling human bioengineers from the future? What, precisely, does the scientific theory of intelligent design postulate that the intelligent designer(s) do to accomplish these designs? What mechanisms does it use, according to the scientific theory of intelligent design, and where can we see these mechanisms operating today? What scientific data or evidence shows that there is only one "intelligent designer" and not, say, ten or fifty or a hundred of them? Intelligent design "theory" is utterly silent on all these questions. Indeed, intelligent design "theory" cannot even make an attempt to answer these questions, since the answers would reveal instantly the religious basis for this "theory", and would guarantee that "intelligent design theory" would never see the isndie of a public school classroom. For this reason, most "intelligent design theorists" go through all sorts of intellectual contortions to avoid explaining exactly who or what their "intelligent designer" is.

< Another question that immediately leaps to mind is "Who designed the Intelligent Designer"? Behe (and the creationists) will of course answer that the "Intelligent Designer always existed". Any "intelligent designer" that exists outside the laws of nature is, however, by definition, God, and God is by definition religious in nature. It is not scientific, it cannot be tested and it cannot be falsified. It is based solely and only on the creationist religious belief that God designed and created life by divine fiat.

The creationists are of course entirely welcome to this religious assumption if they like it. But they aren't saying anything scientific, and as science, "intelligent design theory" is utterly useless. It makes no testible predictions. It answers no scientific questions. It opens no new area sof investigation, and enables no new experiments that could not be performed without it. In fact, there has not been any scientific discovery, of any note, in any area of science, made in the last 20 years as the result of "intelligent design theory". "Intelligent design theory", it appears, consists solely of the assertions (1) we think there is an Intelligent Designer, (2) we don't know what it is, (3) we don't know what it does, (4) we don't know how it does it, and (5) we don't know how to go about answering any of those questions, but (6) we want you to teach about it anyway. Intelligent design "theory" is religious apologetics, nothing more and nothing less.


It is not, then, surprising that the Intelligent Design movement has lost where it has attempted to paint itself as "science". In 2002, the Discovery Institute led an effort in Ohio to modify the state's science education standards to include "intelligent design theory" as an "alternative" to evolution. State officials did insert an addendum ino the state's science education standards that read: ""Describe how scientists continue to investigate and critically analyze aspects of evolutionary theory." The intention of this was to encourage discussion of cutting-edge issues in modern biology, such as the debate over whether birds are descended from dinosaurs or from other archosaurs. The IDer's assumption that this would allow them to present their "alternative science", however, was dashed by another addendum: "The intent of this indicator does not mandate the teaching or testing of intelligent design."


In the face of its Ohio defeat, the ID movement changed its strategy once again, and now only rarely tries to present "intelligent design theory" as a "scientific alternative". Instead, ID advocates now clamor for "teaching the controversy", and argue in favor of requiring schools to teach "the evidence againsty evolution" without specifying what that evidence is or what scientific alternative they want to offer. Alas for the IDers, when this tactic was put into practice in Texas, in November 2003, they lost just as resoundingly. An effort to require Texas science textbooks to modify their treatment of evolution was rejected by the state textbook committee.

http://www.geocities.com/CapeCanaveral/Hangar/2437/design.htm

That's a lot of talking. Now make a cell.

Oh, and by the way, we didn't come directly from apes. Unless of course someone can point me to the direct ancestor of homo sapien? The only species even close to us was Neanderthal, and it's been determined we couldn't have come from them.

Any other contestants?

Originally posted by Darfius
That's a lot of talking. Now make a cell.

Oh, and by the way, we didn't come directly from apes. Unless of course someone can point me to the direct ancestor of homo sapien? The only species even close to us was Neanderthal, and i ...[text shortened]... rmined we couldn't have come from them.

Any other contestants?

Actually, Homo sapiens sapiens and Homo sapiens neanderthalis were members of the same species, merely a different subspecies, because interbreeding was possible. In fact, since the two coexisted, it's likely that HSN were assimilated by HSS rather than going extinct.

No, we didn't evolve from apes; rather several species have been determined as possible common ancestors.

What do you mean by the first sentence? Isn't that bad rhetoric undercutting a creationist position, rather than bad rhetoric aimed at undercutting evolution?

Originally posted by royalchicken
Actually, Homo sapiens sapiens and Homo sapiens neanderthalis were members of the same species, merely a different subspecies, because interbreeding was possible. In fact, since the two coexisted, it's likely that HSN were assimilated by HSS rather than going extinct.

You did not address my question. And no, interbreeding was not possible, as Neanderthal DNA is more different from ours than we are from modern chimpanzees. Would you like to try again?