Religion, Science, Search for Wisdom

Dr. Jerome Lejeune

Proceedings of a Conference on September 1986, Bishops' Committee on Human Values National Conference of Catholic Bishops.


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Introduction

Pascal once said : "Ce que les hommes par leurs plus grandes lumieres avaient pu connaitre, cease religion l'enseignait a ses enfants." ("Religion teaches children what the human race has been able to learn only by the greatest intellectual effort.")

Faith and science express the truth, but their voices are very different. Faith, bestowed by grace, uses a poetic language the heart receives with joy. Science, laboriously earned, offers an abstract discourse the reason masters with pain. It is no wonder that these two paths to knowledge seem at one time mutually reinforcing, at another time in tension, according to the state of our understanding.

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Concordism

When clear divergences came to the fore with the explosive development of physical and biological theories, eminent minds tried to establish a precarious truce through resort to concordism. But, attempting to soften the hard outlines of science or to belittle the heights of revelation led only to repeated failure. In the great days of Laplacian determinism, for example, it was embarrassing to see the sun and the moon appearing on the fourth day. Some concordists argued that an earthbound observer could not see the lights of heaven until the clouds cleared. This is overingenious, to say the least. The state of knowledge in those days did not permit the idea that light could have existed before the sun came to be!

Another example. In the glory days of triumphant neo-Darwinism some ten to twenty years ago, the interpretation of Genesis was changed. Adam could no longer be thought of as an individual. The name, rather, was a generic term referring to a developing race of would-be humans. At this time, biologists believed that whole populations insensibly evolved by gradual steps into a new species over eons of time!

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Discordism

Concordism was progressively replaced by discordism. It became fashionable to see man as an anomaly fortuitously issued from an impassive universe. Our destiny, our duty are nowhere written; we remain forever incomprehensible.

This assertion is the "nul" hypothesis, a useful starting point that makes no assumptions not tied to observation. Observation will tell if the hypothesis must be rejected because it fails to fit available data. Only then can we construct more elaborate theories about humanity.

In the hands of some theorists, however, the hypothesis becomes a proscription. In the name of the postulate of objectivity so dear to Jacques Monod, they decree that no explanation in teleological terms will ever be acceptable. The universe, by definition, has no purpose and is leading nowhere. In a word, they want that God should not exist. It is the discordism of pride.

A strong reaction to so extreme a view is emerging, especially in the United States. Science knows almost nothing, say the creationists. (This, alas, is almost true, but not quite.) Therefore, Scripure must be taken literally; the creationists even add a bit to it. To avoid contradictions, they challenge all the inconvenient facts in advance. They do not want to grant science its legitimate rights. This attitude I call the discordism of despair.

Third and most dangerous, believers tend to withdraw. Fearing open discussion, they steer into "safe" waters. They conceal some revealed truth, hoping to preserve acceptance of what remains. Some catechisms start with Abraham, for example, in order to avoid dealing with Adam. This is the discordism of cleverness. It is not very charitable because it deprives us of parts of the message of life.

It is urgent that we examine the tension between religion and science with our cards on the table. Is there or is there not an irreducible contradiction between revealed teaching and the observed facts?

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The beginning of time

Let us glance at the first day of Genesis. God said, "Fiat lux"- and the light was. Many years ago, Fr. Georges Lemaitre, illustrious president of the Pontifical Academy of Sciences, very aptly drew the conclusion to which the recession of the galaxies led. Hubble had shown that the faster a galaxy is receding, the farther away it is. The universe is a puff of dust blooming in the infinit; that is the meaning of the red shift. Fr. Lemaitre realized that, if this expansion had occurred over a long span of time, the universe was once contained in a smaller volume. At the beginning of time, there was only the primeval hyperdense speck, the source of all matter and energy.

The discordism of pride revolted against this nation of origin. It was too close to the notion of creation. (Recall that in the ancient world the universe was considered eternal. Only Jews and Christians supposed that it had begun.) The tumult died away over the years, since no other hypothesis can account for the facts. In the 1960s, radio astronomers discovered the three-Kelvin backgound radiation, the "echo" of the tremendous event marking the start of space and time. Scientists now generally concede that the universe had a definite beginning some twelve to fifteen billion years ago.

The primeval energy appeared as light; "Fiat lux" is the foundation of modern cosmology. Modestly, we now speak of the "big bang," not the "creation." It is good that physicists do not use the language of theology when they can express the same idea with a noncommittal phrase. Neither concordism nor discordism are relevant any longer; both are obsolete.

As Leibniz foresaw, the models of possible universes are infinite in number, and theorists continue to refine their concepts of the results of such a great and sudden surge of energy as the big bang. It is dangerous, though, to play fast and loose with the basic laws of nature in creating such models, whether the subject is interstellar gravity or the quantum mechanical behavior of atoms. If one assumes much divergence from the observed value of basic parameters, suddenly stars and planets become impossible. The physicochemical laws that allow living beings to utilize energy in order to live no longer apply. And, finally, one arrives at the conclusion that very few models allow for the existence of those who construct the models!

This does not imply, as Engels supposed, that matter is pregnant with spirit so that spirit will inevitably appear in some corner of the universe. It simply means that the laws of nature must be such as not to preclude our existence. This anthropic principle, defined by Brandon Carter, was expressed centuries ago by the sculptor of the portal of Chartres Cathedral, whose scene shows God creating the universe with Adam in mind. Once again, however, physicists are modest . They simply may that we must take human existence into account in examining the laws of the universe. Their logic is irrefutable.

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The forms of life

Let us consider evolution. Two creative acts frame the Genesis account: the creation of the universe at the beginning and the creation of humanity at the end. In between, God says, "Let the earth bring forth vegetation…" (Gn 1:11) and here are the plants; "Let the water teem with an abundance of living creatures, and on the earth let birds fly…" (Gn 1:20) and here are fish and later birds; "Let the earth bring forth all kinds of living creatures…" (Gn 1:24) and here are the animals; and man appears at the end. This dazzling summary tells us the same story, and in the same order, as is registered in those immense cemeteries of geological strata laid down over the ages. How the biblical authors got access to such knowledge science does not know.

Here, the discordism of despair is of no value. No explanatory hypothesis can contradict the biblical text, which does not tell us how the various species appeared. Creationism makes the error of adding an element to the biblical account, that is, the fixity of species. Each species must have been created as such, they say. Therefore, evolution is wrong.

There is a difficulty here, but it does not arise from the Bible, which outlines the steps of evolution. It arises from genetics and paleontology, which show species remaining unchanged for millions (insects) or even billions (bacteria) of years. Hence, the harshness of the controversies raging among theoreticians; reconciling the remarkable stability of species with the successive appearance of various forms of life is far from easy.

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Neo-darwinism

Since species stagnate and life evolves, as Bergson said, there must be a way to pass from one species to another. Darwin supposed that the most convenient way to do so would be through the progressive accumulation of extremely small changes. If small variations occur by random change, the environment will sort them out. Climate, food supply, predators , and other factors will ensure that favorable mutations are transmitted to progeny, while the unfavorable are not. In a very stable environment, species will tend to remain stable, while rapid environmental change will promote the appearance of new forms. Thus, both the stability of species and evolution find an explanation. (Kimura notes that some neutral mutations are not selected either for or against. This adds some fancy to the picture, but the basic argument is unaffected.)

To put it succinctly, neo-Darwinian theory states that mutations are the motor and natural selection guide of biological evolution. Because mutations are random, and their effects are not determined by the environment to which creatures have to adapt, we are led to the blunt proposition that Monod borrowed from Democritus: "Everything in nature is the fruit of chance and of necessity." Such a system requires enormous trial and error, but geological periods are very long indeed. Neo--Darwinists have to believe that, given a long enough stretch of time, blind chance will produce the eye.

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An experiment in detroit

Aside from a few holdovers from Lysenkoism, no one today pretends to have witnessed a new species emerging from a parent one. While we may lack experimental evidence on living systems, however, a very interesting equivalent can be fruitfully studied, thanks to human ingenuity: the neo--Darwinian theory of automobile evolution!

From a biological point of view, an auto factory is very similar to a reproductive organ. All the cars from a given production lineperhaps we should call them a species-are quite identical but for some minor characteristics such as paint color (skin color for human beings). Every part is precisely made in conformity with detailed instructions stored on the magnetic tapes of the factory's computers, tike the genetic information encoded in the DNA in our chromosomes.

All the human genetic machinery has a more or less close parallel in the car-manufacturing process. The parallel to natural selection is obvious. Every novelty introduced into the car will be judged by the consumer. If the "mutation" is superior to the older model, if it performs better, if is is better adapted to the marketplace environment, it becomes a hot-selling item. The factory will reproduce the selected mutation at an accelerated rate, and soon it will replace the old model entirely. It does not matter whether the selective advantage derives from a morphological change--the shape of the fenders-or a metabolic one-miles per gallon. What makes and measures success in the automobile business is the fitness of machine to environment, which determines the number of exemplars produced.

Given this set of facts, a neo-Darwinian bookkeeper at a car company might very logically say: "The whole of automobile evolution can be explained by sudden variations, appearing by chance and selected for and against by market conditions." He would be partly right if technological considerations are overlooked. The president of the company, however, would not be so naive. Suppose we offer a winning formula: "From time to time you just make a random change in your model. If the new model sells well, promote it; if not, junk it. Play this blind game long enough, and you will some day produce everyone's dream car. You may be absolutely certain of success. Nature herself has followed this path since it produced the first amoeba and took, here we are!"

The carmaker, thinking over our proposition, would realize that the more highly elaborated a system, the less likely that a random change will improve it. (Try randomly interchanging two connections on your personal computer and judge the results.) It follows that after each improvement the time required to achieve the next increases exponentially. No banker would underwrite such a random mutation/natural selection system. The time required to produce the dream car would be immeasurably greater than geological time. In real life, "money is time."

The carmaker would no doubt reject our system and instead consult an engineer regarding model changes. The car's previous evolution, after all, was guided by the engineer's discoveries. But we, alas, when faced with biological evolution, have no such option. The mutations we know are random and no one knows of an engineer.

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The ingenuity of life

Perhaps, the engineer is life itself? A few years ago, such a statement would have been considered absurd. Today, we know that complex organisms do not read their genetic message as bacteria do, stumbling letter by letter one step at a time. Complex organisms act tike a film editor. After the cameramen produce miles of film, someone takes scissors to it, removing the useless passages and bringing together sequences that throw light on one another by complementarity or contrast.

While we have begun to recognize this work of recomposition, we do not understand why it is characteristic of complex organisms and not of bacteria. An extraordinary evolutionary jump remains unexplained. It is possible that an enormous gap exists in our knowledge.

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Metamorphosis

The neo-Darwinian story has it that one day a fish with reinforced fins hauled itself painfully ashore and conquered the continents. With the slow improvement of legs over the millenia, this fish's descendents became four-legged animals.

The summary seems plausible, but what about the mechanism involved? Let's consider a frog egg. A tadpole hatches from it. With its gills, its fins, its lateral sensitive line, this tadpole is in every respect physiologically and anatomically a fish. And, yet, one day, without mutation or selection, it loses his tail, grows legs, invents lungs, and becomes a tetrapod. This happens not over millions of years but before our eyes in a fish bowl! Apparently, our tadpole first found in its genes the code for a fish. Then, after a twist that thyroid hormone can trigger, it feverishly reread its genetic blueprint and executed the instructions to make a tetrapod. This tadpole knows more than we do.

And what about cellular differentiation, building bones, muscle, blood, and even brain-the most sophisticated computer ever conceived on earth-all coming out of the single fertilized egg? We are still completely ignorant of the mechanism that drives differentiation, as basic as it is to building up the organism, just as we are ignorant of the mechanism of metamorphosis. How futile it is to pretend we know how an elephant evolved from a primitive mouse, when we still do not understand how a tadpole becomes a frog.

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Species and chromosomes

The order in which instructions are carried out is obviously very important. The DNA molecules that carry genetic instructions do not float in the juice of the cell like noodles in a bowl of soup. Not only are they located on the chromosome in a certain order typical of the species, but the chromosomes themselves have a length, number, and banding pattern absolutely characteristic of a given species.

The horse and donkey will serve to illustrate this reality. They are two different species because their hybrid, the mule, is sterile. Although better endowed for endurance and agility than its parents, the mule cannot procreate. The structural differences between the chromosomes of mare and ass are so great that no equilibrated repartition can be achieved during the maturation of the reproductive cells.

This genetic barrier, due to chromosomes and not mutation, is the very definition of the frontier between species. The sterility of hybrids means that a chromosomal novelty is inevitably selected against. Only when the novelty is received from both parents will fertility reappear, hence, the need for any chromosomal evolution to reach this homozygous stage as quickly as possible if speciation is to occur.

This need is best filled if the first creature homozygous for the novelty reproduces with itself by autofecundation. Such reproduction is quite feasible with plants; all the new species we have developed have been manufactured this way. In higher animals, the separation of the sexes forbids autofecundation. At this level, then, the need is best filled by generating the required couple all at once. Pathology offers an indication of how this might happen.

Extremely rarely, a male zygote, carrier of forty-six chromosomes, including one X and one Y, splits into twins. One of the twins continues its male identity. The other, not having received the Y chromosome, becomes an imperfect female with forty-five chromosomes, including only one X. (Normal females have two X chromosomes.) In my experience, a young girl thus affected complained that she could not look at herself in a mirror because she was afraid of seeing her brother. She was feeling a biological truth of which she was consciously unaware: she was really a fragment of the brother from whom she came.

In our species, "45,X" females are generally sterile (though some have produced children) but, in mice, they are perfectly fertile. The experiment remains to be done, but if a zygote of the type I have described was homozygous for a chromosomal novelty, the couple that developed from it, if mated, would originate a new species of mice.

I apologize for this long excursion into genetic engineering. The hypothesis I set forth would look very revolutionary and very modem and would be considered the solution to rapid evolutionary change if the story of Adam and Eve had not already been so much advertised! Science is very reluctant to discover truths already known for thousands of years.

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Primates and the man like us

Two or three million years ago, an extraordinary flowering occurred in a vast zone ranging from Kenya through Palestine to Asia. New forms appeared rapidly: homo habilis and then homo erectus, whose brain case is larger than that of the modem apes. The causes of these developments are mysterious, but they give the impression of preparations for an important happening.

Some time between one hundred thousand and forty thousand years ago, the man like us, our own kind, suddenly appears. We are really newcomers. As far as is presently known, both Cro-Magnon and Neanderthal belong to our species. As I noted above, Genesis uses the word create when speaking of our origin. Yahweh modeled a woman as companion to the man from the latter's own flesh. "[T]he man said: This one, at last, is bone of my bones and flesh of my flesh; This one shall be called 'woman,' for out of'her man' this one has been taken" (Gn 2:23).

Here is a deep mystery. Genetics can demonstrate that the most narrow consanguinity is necessary for the emergence of a new species, even that a couple born of the same zygote is the optimal way to begin. But, the fact that a special intervention, a creative act absolutely apart from the rest of evolution, was necessary for the emergence of our species is pure revelation-but not a real surprise.

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A curious phenomenon

Man is a curious phenomenon, He stands erect; manufactures took, and speaks. To some extent, one can even rely on what he says. Anterior forms, however, were bipedal one or two million years ago. The first chips of stone may date from the same era. Some endocranian impressions suggest that Broca and Wernicke zones were sufficiently developed to allow a primitive communication system even in homo habilis.

The full novelty, the absolute superiority, consists in the fact that man is the only creature able to experience a kind of connivance between the laws of nature and his feeling of existence. The faculty of admiration is solely human. No dog ever tasted the fragrance of a rose. No chimp ever contemplated the sunset or the splendor of the starry sky. The one who was the first to know he would die and built tombs; the one who helped wounded fellows and protected their weakness; the one who discovered art and pursued it far beyond mere technique; this one who is us-and not a hundred thousand years old-possesses something like a spark of the intelligent love.

Besides the difficulties it presents at delivery, man's large brain is an enigma of natural selection, as Alfred Russel Wallace was the first to recognize. Before we could develop our ability to decipher the laws of nature, leading to such achievements as unleashing the power of the atom and visiting the planets, generation after generation had to accumulate a fantastic store of knowledge. How could natural selection anticipate the need for this knowledge? That the world is intelligible, even partially, is perfectly unintelligible, unless the Spirit who enacted its laws also created us in his own image.

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The rib, the trees, and the garden

Let us glance again at the Genesis account. It refers to Adam's rib or, more precisely, pair of ribs. Why associate the birth of our species with the loss of these small bones? Modern exegetes embarrassed by this anatomical precision might be interested to know that our nearest cousins, the gorilla and the chimpanzee, have thirteen ribs to our twelve. There is no need to attempt building a new concordism on this circumstance. On the other hand, it is wise to transmit the whole message untouched for the sake of science's continued evolution. Theories fade away, but the truth is everlasting.

During discussion following a talk I recently gave on the origin of the human species, after I had described the "one-couple expedient" as suggested by genetics, a knowledgeable member of the audience called out: "Let us suppose you attained your bipedal being, naked, without fangs, without claws… and capable of admiration. How will you protect it from the first predator that comes along?"

"With your permission, sir," I replied, "I will place him in a carefully preserved park, an agreeable garden."

"And, will you take care that it does not pick up some toxic food that could unbalance its mind?"

I did not answer. A poison paralysing the connections between the affective network and the intellective one and capable, at the same time, of modifying the primitive genetic instructions that dictate the makeup of these parts of the brain… I cannot describe such a poison in scientific terms. Yet, philosophers down through the ages have noted the existence of a primeval fault in our makeup. It consists of an inability to integrate the emotional and the logical. Most of the time, the heart and the head are not on speaking terms!

With this consideration, we are back to our starting point. Revelation speaks to the heart, experiment to reason. Can we ever integrate them? It has happened once.

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A sign in the heavens

Some two thousand years ago, a delegation of astronomers came to Jerusalem from the East. They had observed a moving, sign in the sky that, according to their calculations, announced some sort of good news. They had derived the direction in which to search, but not the precise location.

The astronomers had an audience with the king, who immediately summoned his counselors. They did not understand the situation but sensed that there was something to fear; good news is not necessarily good to the establishment. To leave no stone unturned, the king interrogated theologians. They revealed that a minor prophet had once written: "But you, Bethlehem-Ephrathah, too small to be among the clans of Judah, From you shall come forth for me one who is to be ruler in Israel; Whose origin is from of old, from ancient times" (Mi 5:1).

So, the Magi were to go to Bethlehem. They felt great joy when the sign in the sky stood still, confirming this advice. Thus, they made the most admirable discovery: the creature conceived in perfection, having, by the action of the Spirit, given birth to the new Adam. They saw the Virgin and the Infant.

This story is marvelous not only because it is true but also because it points the way to a healthy relationship between science and faith. The Magi did not doubt the competence of the theologians. They decided to go and see.

For their part, the theologians did not raise their noses from the text. Perhaps, I am reading in here. Matthew is a charming storyteller, however, and he would not have missed the chance to portray Herod, his court, and his experts craning their necks to catch a glimpse of what the Magi were admiring. I am sure they did no such thing. And, even had they gone, they would not have seen what the wise men saw. Great patience is needed to decipher nature.

Thus, teamwork led people of good will to the highest truth. Everyone conscientiously listened to the other without scanting his own hard-won knowledge. As for the political power, duly enlightened by faith and informed by science, it behaved as usual. Invoking reasons of state, it massacred the innocents.

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The children of men

Our own time is witnessing the same thing. All molecular biology teaches us that human nature is given at conception. The most recent technology, in vitro fertilization, demonstrates that a new being comes into existence at conception. The most sophisticated ultrasonic scanning shows us the two-month-old baby performing, in the mother's womb, a kind of dance, full of grace and youth. The Church teaches the same unchanging truth. Nevertheless, the political power has reversed by vote what doctors have sworn to for more than two thousand years: "I will not give poison; I will not procure abortion."

Then, one receives in the heart this terrible revelation transmitted by our Lord himself, this decree incomprehensible yet absolutely obvious. "I offer you praise, O Father, Lord of heaven and earth, because whit you have hidden from the learned and the clever you have revealed to the merest children" (Lk 10:21).

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Discussion

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Dr. Dennis doherty :

With regard to Dr. Lejeune's comments on the use of noncommittal language, our group feels that scientists should explain things in terms proper to science. Let them speak their own language. We feel, too, that people of religious faith have a responsibility to interpret, in religious terms, what science talks about.

We have two questions for Dr. Lejeune. First, How do you view the recent works of Eldridge and Gould regarding the long-term stability of species? Second, What ought to be the goal of dialogue between religion and science? We found benefit in Fr. Ashley's response. Granted the stance of the believer, science can paint in the details.

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Dr. Lejeune :

I would say that Eldridge and Gould improved upon previous knowledge that sometimes new species emerge very rapidly in geological terms. It is a very interesting discovery, but it does not change my views because I have never been a believer in strict neo-Darwinism. Gould's intervention is most agreeable to me because it seems to be true.

What should the goal of the dialogue be? I said at the beginning that religion speaks to the heart and science to the reason. Interest in the dialogue reflects the human dignity of putting together the feeling of the heart and the deductions of reason. That is what is called a state of grace.

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Dr. Frederick Lawrence:

Our group was most impressed by Dr. Lejeune's genial reincarnation of the spirit of Pascal. When one is a serious scientist and, at the same time, a serious believer and allows the two things to illuminate each other, it is an impressive and wonderful thing, no matter how many difficulties emerge.

We also wonder about what you might call "the dynamics of high vulgarization," when scientists and religious leaders talk about their differences. I have heard scientists use Scripture in a way that could be labeled unprofessional. On the other hand, how scientists must squirm when theologians make pronouncements on matters where they are less than expert. How do we deal with this?

We made some observations on what happens when the two cultures of religion and science are Combined in the ame person. In most of our experience, the younger the person the greater schizophrenia there is between the religious and scientific aspects. Older people, on other hand, tend to be more "myth-loving," to try to bring everything together. We wondered how priest-scientists resolve these tensions.

More attention should be paid, we feel, to the discordances between religion and science, to the different character of the truth claims that each makes. Science operates on the presumption that its conclusions are merely probable, that they are open to revision. Catholic theology, in fact most Christian theology, claims that at least some of its statements are not open to revision. What happens to theology when it moves too far in science's direction? Doesn't it have to remain faithful to its foundations in religious belief? But, can it maintain intellectual probity without gravitating toward science?

Science has a responsibility to accommodate itself as well. Foundational issues arise in all the sciences. It belongs to the integrity of science to face these foundational issues, and this means interchange with philosophy, theology, and religion. What are the criteria of truth in these different universes of discourse? We need to define what we mean by religion, faith, and science.

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Dr. Avrom Blumberg:

The question arose in our discussion as to whether scientists need to invoke creation to make sense of the world. Scientists are very frugal with models; we hate to go out on limbs. Also, whenever an explanation is given, it always leads to another question. So, we prefer to describe rather than to explain. The big-bang theory is an adequate model, but it doesn't at all explain what brought all that matter or energy together in the primeval spark.

Dr. Lejeune makes a point that also fascinated Einstein, namely, that there is no particular reason why the world should make sense. He puts it this way: "That the world is intelligible, even partially, is perfectly unintelligible, unless the Spirit who enacted its laws also created us in his own image." There may be an opening to fruitful discussion here. Scientists have faith that there is order and design in the universe. Historically, this notion came from the concept that there is a God, so, in a sense, belief in God gave rise both to religion and science.

Our group discussed, at length, the fact that theologians rarely have scientific backgrounds. A number of theologians have remarked that their seminary training did not include any course in science. It was also pointed out, however, that one year of science usually does no good because science is presented as a finished product; the student doesn't get a clear idea of how science shapes its models.

Finally, we wanted to ask Dr. Lejeune whether he is suggesting that the Genesis account of human creation is a fact.

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Dr. Lejeune:

You want to know if I consider the creation a report of a historical phenomenon? I have no information on that score. I am interested in trying to discover, from what we know about cytogenetics (the mechanics of the chromosomes), the best model for building new species with the highest probability of getting a correct result. It appears, from the equations of population genetics, that a very tiny population is necessary as regards evolution at the human level. The closer the consanguinity, brother and sister mating perhaps, the greater the probability that a change will reach the homozygous stage and that a new species will be built from there. So, one is led to propose the couple born from a single egg as the starting point for the human race. Thus, I constructed my theory.

I did not attempt to prove this theory in my talk; I was merely discussing a possibility. Now, let's suppose that we have done the experiment I proposed, that we have done some genetic engineering and succeeded in building a new species of mice, recognizable as such and entirely sterile with respect to the original population. Let's suppose this is possible. Even this experiment would not prove that Adam and Eve are a historical fact. It would only demonstrate an interesting system for building a new species: taking the female out of the male. Did it happen that way in the particular case of humanity? God knows.

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Fr. Mcmullin :

I want to make an observation first and then ask a question. I was charmed by the Gallic eloquence of our speaker. He is in the great tradition not only of Pascal but of Teilhard de Chardin. I heard echoes of a long tradition of poetry and rhetoric as well as of great science.

I was a student of Fr. Lemaitre when Pope Pius XII gave his allocution to the Pontifical Academy of Sciences in 1951. I had Lemaitre in a seminar shortly after he came back from the Academy meeting, and he was upset at the way the pope had used his big-bang theory as almost a proof for the existence of God. I still remember one of his comments, which has turned out to be scientifically prophetic: "How does His Holiness know that the big bang wasn't preceded by a big squeeze?" As we all know, the cyclical universe is now considered a possibility.

Lemaitre would have been perfectly happy to acknowledge a broad resonance between religious and scientific opinion in this matter. He would have agreed that, if God created the universe at a moment in time, that moment must have looked something like a big bang. But, that was as far as he would be willing to go in the way of argument.

Fred Hoyle, by the way, was also upset by that allocution and deliberately used the term creation for his own opposing theory, the "continuous creation" view. (His coworkers called it the "steady state theory.") That particular view went down in the 1960s, of course, because of the discovery of the three-Kelvin radiation.

I have a question regarding something I find troubling in your talk, Dr. Lejeune. I want to press you a little on this, just as I would have pressed Bergson or Teilhard, because I catch echoes in your thought of theirs. The question is prompted, in part, by your choice of the "Detroit analogy." As you pointed out, engineers are in charge of these automotive "mutations". So, they aren't random mutations.

Most people in evolutionary biology today, I think, would agree that the neo-Darwinian synthesis is not a final account, that it doesn't explain everything. Most would say neo-Darwinism has correctly outlined the process and identified the proper explanatory resources, though some additions may be needed. You proposed an extremely interesting conjecture regarding the origin of species. Should we take your suggestion as yet another in a long line of amendments to the neo-Darwinian synthesis? Or, are you suggesting, since you criticize the notion of chance, chat somehow evolutionary events are not chance-that there is an elan vital or psychic energy moving through the process? How are we to construe the notion of chance in the light of your remarks?

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Dr. Lejeune :

That is not easy to answer. First, let me say that, while I like the writings of Fred Hoyle, he was wrong to use the term creation in describing his steady state cosmology. If his model is true, nothing is created.

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Fr. Mcmullin :

According to him, one atom of hydrogen was created every million years or so per cubic yard of space.

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Dr. Lejeune :

But, it was not created out of nothing. It was created out of a "special property of the void".

You asked about my criticisms of neo-Darwinism. First, what I propose about chromosomal mechanics does not come out of the blue. We know that each species has its own chromosomal makeup. That must mean something; we cannot ignore the fact. Yet, it has been entirely ignored in books about evolution. Second, you will never find an entry for metamorphosis in the index of a neo-Darwinian book. This suggests to me that those who write these scholarly books about evolution, about neo-Darwinian theory, have deliberately overlooked the fact that there are many ways of looking at the same genetic makeup. A tadpole does a fantastic job of climbing the taxonomic tree in fifteen days' time.

I suspect that behind the chromosomal mechanism there lie special phenomena of living systems that will entirely change our view of evolution. If you want to press me to the limit, I can tell you what I feel. It is just a feeling, an imagination, an opinion, not a scientific demonstration. I believe that the genes in the chromosomes are disposed in such a way that the genetic message, during the life of the cell, is expressed three-dimensionally. Generally, we think of this message as written on a linear molecule so that it is a linear system, like a magnetic tape. But, I suspect it is not like that in the living cell.

My hypothesis is that, with the specialization of the cell-whether it becomes a brain cell, an epidermic cell, or an hepatic cell-a particular way of reading this message develops. For example, segment A of a given chromosome is placed in proximity to gene B of another chromosome so that A and B can be read in order or so that A can act on B, turning it on or off.

Step by step, these chromosomes will constitute a three-dimensional design, very comparable to the logical network of a computer-the wiring being specific to a given tissue or organ at a given moment of the development of the individual from the egg state to the completed adult. Time, so to speak, is progressively incorporated in this progressive network.

So much for specialization of cells. Let's look at evolution. Let's suppose that an accident, a chromosomal mutation, occurs so that genes A and B, which only came in contact after quite an elaborate process of cell differentiation, are now definitely joined in a rearranged chromosome. If this accident happens in a reproductive cell, it will give to the next generation logical information built in the linear order of the new chromosome; a fantastic acceleration of the developmental process!

This chromosomal novelty should not be considered purely random; first, because it happened between two points that had already been placed in proximity by a physiological process; and, second, because it encodes in the linear message an information that was previously expressed in the three-dimensional construction. If such a novelty establishes itself in the homozygous state, it will modify the resulting network, hence the physiology.

One can then suppose that the next chromosomal change to occur in this lineage will have some causal relationship with the previous one. In other words, a given line will obstinately move in its own particular direction. The ancestors of horses try to become more and more horse-like, not cow-like.

Certainly, these very simple and rough ideas do not pretend to represent a new theory of evolutionary forces. But, my strong feeling-you asked for it-is that some day we will better understand these processes and discover some logic underlying apparently random accidents. The neo-Darwinian model does not provide this logic. Nevertheless, it must exist.

To illustrate: a chromosomal rearrangement in a cancer cell may place gene A (an oncogene) into proximity with gene B. The behavior of the cell changes as a result and, depending upon the chromosome involved, a leukemia of such and such a type, perfectly recognizable, is produced. Hence, the hypothesis that chromosomal changes can modify the makeup of an organism (and, if established, produce a new species) is not pure fancy. It is just an extrapolation of what we have learned in the last five years about the evolution of cancer cells.

It is futile to pretend to the public that we understand how an amoeba evolved into a man, when we cannot tell our students how a human egg produces a skin cell or a brain cell! The very broad field of research I have outlined may give us some hints about both phenomena. It is hoped that it will give us new and better ideas.

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Fr. Ashley :

You mentioned than species can be recognized on the cellular level by chromosomal number and shape. We also know that the human species includes poeple with forty seven chromo somes-for example, those with trisomy 21. If you tried to define the human species in terms of forty-six chromosomes-the "normal" number-you would have trouble with the person who has forty-seven. Somehow, the definition has to take this reality into account. My first question is this: Would the definition of species be more complete if it included chromosomal banding?

My second question also has to do with species. In zoology, an individual is said to belong to a certain species when it can only breed with members of that species. Is fertility the only external test we have to determine species? What constitutes a really new species in the sense in which you are using the term?

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Dr. Lejeune:

I accept the Aristotelian notion of species: the members of one species can crossbreed and their progeny is fertile. Also, it can be said that individuals who crossbreed are more similar than others who cannot. That is true and is the taxonomic definition, but the species identity is related to its karyotype, the shape of its chromosomes. Indeed, banding pattern helps greatly in recognizing the fact that each species has its own peculiar karyotype.

You ask me whether I should say that a Down's syndrome baby is not a member of our species because he has forty-seven chromosomes instead of forty-six. Well, he has one chromosome too many-three exemplars of pair 21-but, the other forty-six chromosomes are typically human, not chimpanzee-like or orangutanlike or gorilla-like. Hence, I see him first as a man, second as a patient with a disease-trisomy 21. If this patient later procreates, fertility will be observed.

On the contrary, if two individuals differ by their specific karyotype rather than by a simple error as in Down's Syndrome, we can safely predict that hybrids, if possible at all, will be sterile, as in the case of horse and ass. This explains why I use a chromosomal and genealogical definition of the term species. I realize that some people are using species more loosely, in ways that seem to me scientifically unuseful. I will go a little further and say that I have a deep respect for Darwin, but not his use of English. If he had called his book The Origin of Races, I would be a Darwinian. Unfortunately, he called it The Origin of Species, and I cannot accept it.

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Dr. Wilson :

This is fun because it is beginning to turn into a lively scientific debate. I don's want to take too much time, but I felt I must say that I recognize very little of modern biology in what Dr. Lejeune is saying. I find the model that he is presenting, insofar as I understand it, singularly unconvincing and without a shred of evidence. It seems an attempt to revive orthogenesis at the molecular level. It should also be noted that his view is surely shared by less than one percent of the biologists of the world or, at least, the Western world. I myself know of no active evolutionary biologist in the United States or Great Britain who shares such a view.

I realize discovery lies in recognizing that all great oaks from small acorns grow. Today's heresy may well be tomorrow's orthodoxy. Nevertheless, Dr. Lejeune, the definition of species you have given is shared by scarcely any modern evolutionary biologists.

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Dr. Lejeune :

I know.

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Dr. Wilson :

A species is defined almost universally now-and it has become very effective as an operational definition-as "a population or series of populations isolated reproductively from other populations under natural conditions." It has been demonstrated in many animal species, particularly insects, that a single gene difference or a very small number of polygenes can quickly produce species. Take this case, for example: a biological species is reproductively isolated from another. Fertility is not required because premating isolating mechanisms-that is, ones that stop any attempt to mate prior to the actual formation of the fertilized egg-can be and demonstrably are equally effective. Molecular changes in a single sex pheromone, for example, have been sufficient to create species.

I was dismayed earlier by your analogy with the factory process. Whereas the manager of a Ford assembly plant would definitely be unwilling to stake the business on the success of a modification in the fender, this does not reflect the situation in nature, where profligate discard of parts is routine. There are between one billion billion and one hundred billion billion organisms alive at any given time on the earth's surface, many of which have life spans of only a few hours. Each one of these, depending on the organism, has between one thousand and ten billion nucleotide pairs. Thus, the arena of evolution by natural selection is almost unimaginably large. Nature's prodigious discard of nonworking parts has resulted in the extinction of more than ninety-nine percent of the species lines that have ever existed. Most biologists, and not just neo-Darwinians, see this process as adequate for explaining a large part of evolution.

You expressed puzzlement over the role of metamorphosis-the transformation of tadpole into frog. This is no mystery at all. Metamorphosis is easily fitted within the neo-Darwinian scheme. The relevant genotype evolved over a long period of time. This genotype includes multiple sets of genes so organized that the activation of one gene set produces one phenotype and the activation of another gene set produces another. Molecular genetics can explain this mechanism quite well. I must rise heartily to the defense of neo-Darwinian theory. The group will find me substantially more dogmatic and inflexible in this case than I was in the face of God.

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Dr. Lejeune :

You say that only one percent of the geneticists now living are dissatisfied with neo-Darwinism. Does this mean that less than one percent will eventually accept a chromosomal hypothesis?

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Dr. Wilson :

No, I meant that less than one percent of active biologists would agree with your dismissal of neo-Darwinism. That is totally different from saying that neo-Darwinism has fully explained everything. It is a non sequitur to argue on the basis of large gaps in our understanding of developmental biology and the speciation process that neo-Darwinism is bankrupt and must be replaced with another orthogenetic theory.

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Dr. Lejeune :

In that case, I fully agree that less than one percent of the world's biologists would accept a new theory of evolution through chromosomes. It is a pity. I say that in all seriousness. In the face of evidence derived from all species that the chromosomal structure is so intimately involved in the speciation process, how can you construct an evolutionary theory that does not take this basic phenomenon into account?

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Dr. Wilson :

I think there must be some misunderstanding. The role of cytogenetics and chromosome mechanics as primary processes in evolution, and in fact as part of the phenotype of evolution, is well worked out and integrated into neo-Darwinian theory. I don't follow your argument that they have been neglected.

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Dr. Lejeune :

The notion that chromosomal change is what is important in evolution has significant implications. Chromosomal change will be selected against as soon as it occurs. On the contrary, if a small mutation has even a tiny selective advantage, it can grow in the population and be accumulate. That is one basic difference between the two explanations. The second difference is that we have strong reason to believe that chromosomal changes are not random, while most mutations do appear to be random. Obviously, we are dealing with two distinct ways of building an explanatory model.

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Dr. James Courtright :

The gaps that have been talked about are in fact being closed. I now of many instances in the last few years of recombinant procedures where genes have been replaced in mammalian and other cells. Genes, by themselves, can be put back into systems and expressed in a very specific way so that the gene itself is responsible for its expression in a given tissue at a given time. Moreover, we now know that enormous numbers of mobile genetic elements are present in eukaryotic chromosomes and that they are responsible for changes in these chromosomes. These discoveries are relevant to the questions Dr. Lejeune has been raising. A great deal of molecular information exists that allows us to understand evolutionary mechanisms in the neo-Darwinian context.

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Participant :

I thinly the gaps in neo-Darwinism's ability to explain evolutionary change are there, perhaps even more radically than Dr. Wilson was acknowledging. I am not clear, however, where you are taking this point, Dr. Lejeune. Are you saying that these gaps will be filled by more complete scientific analysis of the chromosome structure? Or that a more wholistic view of the interaction of the total organism with the chromosome is required? Or that, in the last analysis, chromosomal changes are not random but are controlled by God or by some other force? Would you care to comment on the religious significance of the gaps?

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Dr. Lejeune :

I do not find any religious significance in these gaps. I do assert that we do not take chromosomal mechanics and chromosomal physiology sufficiently into account in explaining evolution. And, we are wrong. We will do so sooner or later.

I don't know how long it will take before we can produce a more refined model than neo-Darwinism. In my view, neo-Darwinism is like the epicycles of Ptolemy: an explanation useful for the time it was proposed, buy which did not exhaust the reality. In due course, Ptolemy's system gave way to the Copernician system, a better explanation. I think we are in the same place as regards evolution. Neo-Darwinism is a marvelous mathematical construct, as the epicycles of Ptolemy were. But even Ptolemy himself knew his calculations did not entirely fit. In the same way, we know that neo-Darwinism, as it is taught in the universities, does not give us a really satisfactory explanation, and we know further that there is one branch of science that is not incorporated in the theory. Obviously, somebody someday will produce a much better system. He will be evolution's Copernicus.

My interest in those gaps does not arise because I would like to squeeze in divine action. I do not believe that God manifests himself only where science fails! The fact that science exists at all is to me a clear manifestation of God. But, our theories are far from satis-factory, and we must fill the gaps with more and better science.

Now, there is one idea to which I am very open, however. Man is a very extraordinary anomaly compared with the rest of the living kingdom. It would not surprise me, as a scientist, if a touch of genius went into designing him.