Painting by Hans Holbein the Younger (1517)
Here is a solid orthodox Catholic presentation of our belief in Adam and Eve, in light of present-day science, from exchanges with a dedicated Darwinian. Dr. Bonnette wrote in his letter to me:
As you may recall, my book, Origin of the Human Species (Sapientia Press, 2003), defends the reality of Adam and Eve. . . . Nothing is more central to the Judeo-Christian religious tradition than the reality of Adam and Eve, for reasons you know even better than I. . . .His words follow (from files he sent along):
From Reconstructed discussion whether belief in literal Adam & Eve is warranted
by Dennis Bonnette, Ph.D. 3 June 2009 A.D.
re posts 276-282:
Well, I expected a very detailed and strong response from you, and you did not disappoint me!
Unfortunately, I think we are beginning to go over the same ground.
What I see developing in comments on this thread are three positions:
(1) Divine revelation trumps certain present claims of natural science. Specifically, this occurs when a claim made on behalf of natural science crosses the epistemic boundary between natural science and theology. A prime example would be a natural scientific challenge to the Catholic Church's definitive teaching that Adam and Eve actually existed as the two first true human parents of the entire human race.
(2) Certain evolutionary theories appear to trump the truth of divine revelation.
(3) Some deny that divine revelation requires belief in the literal reality of Adam and Eve.
There is no doubt that Catholic teaching demands the literal reality of Adam and Eve, as has been superbly documented by masterjedi747 (post 287). You appear to place primary emphasis upon natural science in determining whether belief in a literal Adam and Eve is warranted, but you also mention #3. While #3 has been brought up in other posts, the key issue remains the reality of Adam and Eve as first parents.
Clearly, and understandably from your perspective, what you see as compelling scientific evidence against a literal Adam and Eve primarily moves you to dismiss all possibility of Adam and Eve. Despite the extensive philosophical and scientific arguments you present, you do not address the evidence of miracles supporting Catholic belief and teachings. As GrannyMH so aptly points out (post 284), "Divine Revelation trumps." The fact that you cannot accept this sort of evidence is unfortunate, but does not make it go away. The more one studies the details of these extraordinary phenomena, which God alone appears able to produce, the more difficult it becomes to discount and ignore them.
In addition to other sources I have previously mentioned documenting the miracles that fill Christian history (posts 237-238), I suggest The Whole Truth about Fatima: Science and the Facts by Frere Michel de la Sainte Trinite (Immaculate Heart Publications, English edition, 1989), vol. 1, pp. 323-356, which describes in great detail the miracle of the sun at Fatima in 1917, examining relevant scientific, philosophical, and theological aspects.
St. Thomas was well aware that miracles cannot compel belief. The Fatima "miracle of the sun" will always tempt agnostics to appeal to something like "collective hallucination" (meaning, everybody was suffering from mental illness!) or that space aliens arranged the whole episode using natural technology too advanced for our understanding. Still, especially for those who accept God's existence, at some point naturalistic explanations become less intellectually credible than acceptance of a genuine miracle. As I said in posts 237-238, "While no one can force anyone to believe anything, Catholics may rightly "warrant their belief" in the Catholic Church based on this continuous history of miracles, beginning with the Resurrection itself -- miracles largely filled with Catholic specificity." And Catholic teaching affirms Adam and Eve.
Does natural science regulate philosophical and theological science, or does theological and philosophical science regulate natural science? (I am sure we both see nuances here, but the central contest should be evident.) In cases where a claim is made about an issue pertaining to both natural science and theology, which discipline must have the last word? The Catholic scholastic tradition holds that theology is the supreme science, the "queen of the sciences," and that philosophy is "theology's handmaiden." I am sufficiently predeluvian to be happy with that scenario!
As I have said before, you are not merely speaking on behalf of natural science here, but also a philosophical position through which you interpret natural science (pragmatic verificationism?). If one wishes to speak with the authority of natural science alone on any topic, then all philosophies must be set aside. But that is not possible. The method of natural science itself necessarily presupposes, as I have pointed out before, absolute acceptance of such philosophical first principles as identity, excluded middle, non-contradiction, sufficient reason, and causality -- as well as epistemological realism.
That is to say, every scientist presupposes that observations are what they are, that they cannot both be and not be what they are, that phenomena have reasons and explanations, and that we can make accurate observations of the extramental world. If you fudge on these first principles at any level, you undo the very method by which you built up the scientific models which led to your "fudging."
This all means that you cannot do science by itself. It either operates on blind faith, or else, presupposes some philosophical "framework" in which its findings are accepted. Yes, that means that philosophy is regulative of natural science in a certain foundational sense -- and why any "findings" of natural science which challenge its very presuppositions are absurd and impossible.
That also means that we must bring contending philosophies to the table in any discussion of scientific evidence as well as such claims as a literal Adam and Eve. I do not propose to reargue here the points I made in posts 260-261. Your materialist and sensist philosophy does not see the same world which my Christian one does. Still, I would make two observations:
1. The point of Christian philosophy (Thomism, if you insist) is that true human beings possess intellective powers which are essentially superior to mere sensation, which (sensation) they share with beasts. This means that above and beyond the mere animal ability to grasp the physical, sensible qualities of physical objects, the human mind can penetrate to the very essence of things -- understanding their intrinsic natures, including, as Eddington expresses it in his book, The Nature of the Physical Universe.
This is what marks man's entrance into a world undergoing biological evolution: A creature appears which is able to understand his own presence and role in a world whose myriad entities he grasps in their very substance and nature, not merely -- as in the case of brute animals -- as collections of physical appearances or images to which they instinctively or reflexively react. Sensism and materialism allow no such radical distinction between man and brute. Christian philosophy sees a qualitative leap to true humanity in this essentially distinct intellective mode of cognition. For a sensist to grasp and affirm an essential difference between mere sensation and true intellection is an oxymoron.
2. You appear well-versed in the writings of both Aristotle and St. Thomas. That is why the following quote from you (post 280) surprises me:
So we turn to your claims about the existence of a spiritual dimension and about how consideration of philosophical species indicates that a substantial form exists, separate from any material form and sovereign over it, and which determines our intellect and free will, and provides us with personal immortality. This is a very pretty concept, but there is not an iota of evidence in support of any of it. As I have pointed out several times, if we shed all of our preconceptions and our desires for the world to be as we would like it to be, we must conclude that none of these beliefs is warranted.If you know Aristotelian hylemorphic doctrine, the human spiritual substantial form is not a thing in itself, operating entirely separate from the organism of which it is the form. Form and matter are co-principles of one and the same human organism. Since the (passive) intellect takes as its object the impressed intelligible species, and since the agent intellect forms that species by a process of abstraction from the phantasm which is formed in the imagination as a result of the impressed sensible species coming from the external senses, it is clear to all Aristotelians that no operation of the intellect is possible in this life without extrinsic (NOT intrinsic) dependence upon sense faculties and material organs, such as the brain -- since external sense stimuli and organic operations are presupposed to provide the data on which the sense and intellective faculties act.
First, the evidence for human faculties is quite unequivocal: no human faculty exists that does not depend on neural activity. No human faculty exists that cannot be affected by physical effects. No human faculty of self-consciousness or consciousness of the external world or abstract thought or speech or reasoning or prayer or poetry or music or morality or free will exists in the absence of a physical brain.
Arguments for the spirituality of the intellective soul are based on the intelligible objects formed by the intellect -- its mode of knowing, NOT because it can operate when the brain is not functioning. Materialist arguments against the spiritual soul fail to grasp its proper operation, and why that operation is intrinsically spiritual. No empirical evidence by itself can disprove what pertains to the reality of spiritual faculties.
Without spiritual faculties, modern human sciences would be impossible, for they depend necessarily on concepts and judgments, which cannot be derived from organic powers. Similarly, while I grant that fossil evidence for human activity varies over time, you claim (post 278) that such evidence precludes a first true human being. I already answered this in my above-mentioned posts when I said:
The fact that gradual improvement in tool making or other activities takes place over time does not prove that a radical line of demarcation is not present. At some point in time, true man became present. Before that he was not, and what we find are simply signs of complex sentient behaviors of lower animals, including subhuman primates.I also pointed out there that the stable nature of man is consistent with the fact that his powers are not always in act, and that their sudden appearance would be mixed with evidence of purely sensory abilities which he shares with brutes. The fact remains that spiritual souls cannot "gradually emerge," since a primate either has one or not.
The need that there be a first true human (Adam) at some point in time, with a spiritual soul directly created by God, remains.
As to your extensive comments from molecular biology (posts 276-279), they say precisely what I have already written (posts 265-266). First, "...careful reading of your posts suggests to me that your conclusion about the scientific consensus is not based on the question of effective population size, but rather on other aspects of specific genes." Your careful efforts (post 277) to show that "... the concept of a human population increasing from two to 10,000 in ten generations is not practically tenable...." suggest to me that the project may actually be possible in principle. You grant the mathematical possibility, but then cite various refereed papers arguing that such rapid population growth would be unheard of according to natural scientific experience and estimates.
May I respectfully suggest that God might be able to arrange the needed conditions -- not necessarily by miracles, but by providence -- in a time so short and so deeply hidden in the recesses of prehistory as to be totally unobservable to modern scholars? You assume that you have demonstrated that a bottleneck of two is impossible. Inductive arguments do not demonstrate impossibility, only improbability. Furthermore, a person can be shown to be mistaken about contingent empirical claims without having to cite a scientific paper. God does not write in refereed journals.
Regarding aspects of specific genes, I had already conceded:
You have built a powerful case to prove that other specific genes in the genome indicate in various ways that a bottleneck smaller than one thousand appears impossible.In anticipation of your impressive response, I had also written:
... I am confident you will inundate me with much more supporting evidence and 'absolute certitudes,'... the difficulty is that we may find out something 'surprising' about gene behavior in the future -- just as we did in the case of Ayala's 1994 claim.What is apodictically clear, though, is that the Catholic religion teaches the reality of Adam, regardless of what secular scientists may speculate about human origins. As I indicated early on in this post, the theological basis is certain, and, in Granny's immortal words, "Divine Revelation trumps."
Moreover, there is an inherent uncertainty 'built into' any attempt to determine absolute certitudes about specific distant past events based solely upon microscopic analysis of present evidence, especially when much of the science is of very recent vintage and entails many assumptions and estimates. Unlike Catholic dogma, this is not the stuff of divine revelation.
That is why I said at the beginning of this post that we are beginning to go over the same ground.
That is also why I still maintain that it is reasonable for 21st Century, educated people to believe in a literal Adam and Eve.
THREE RESPONSES TO A DARWINIAN'S CLAIMS AGAINST A LITERAL ADAM AND EVE
Dennis Bonnette, Ph.D.
I. Some philosophical reflections pertinent to Adam and Eve: [Posts 260 and 261]
The purpose of this post is not to open lengthy debate about the details or credibility of certain foundational themes of Christian philosophy, but rather to examine questions that are more specifically relevant to Adam and Eve's existence. Those who reject these basic claims may do so, but for Christian philosophers, these are some of the logical presuppositions which help render reasonable belief in a literal Adam and Eve.
First, God exists, and can therefore play a special role in Adam's creation as well as in human history. Christian philosophy maintains (in accord with Catholic teaching) that God's existence can be known by the light of natural reason. Major Christian thinkers (also some pagans) down through history -- scholars well aware of the distinction between theology and philosophy -- have defended philosophical proofs for God's existence. The fact that atheists and fideists reject these proofs is hardly news. While it is perfectly legitimate to criticize and debate whether God's existence can be proven, that project would be a sure recipe for endless digression, never getting around to dealing with topics more specific to Adam and Eve.
Second, man possesses a spiritual and immortal soul, which God alone can create. Christian philosophers maintain that God has created some sort of special nature in man, a nature distinguished by intellective and volitional activities that separate him essentially from the rest of the animal kingdom. Again, both pagan and Christian thinkers have reached similar conclusions for purely philosophical reasons. These conclusions again could be debated endlessly. But I suspect most readers here would rather know whether this claim makes any sense in terms of what we know of human origins from natural science.
The difficulty raised by natural science appears to be that the paleological record does not seem to fit with the notion of a single first man, somehow instantly essentially superior to all previous lower animals, especially to subhuman primates. The reason for this objection is what appears to be the very gradual changes in tool-making ability and other behaviors of primates over great spans of time, all of which argue against the sudden appearance of a first true human being, or beings, who are essentially superior to prior primates.
Philosophical concepts essential to this claim are that true man possesses a substantial form, which unifies, specifies, and makes actual the presence of the intellective, volitional, spiritual person of an animate nature -- and that this qualitatively superior step in nature and being is such that it represents a line of demarcation which is not amenable to gradual development. Materialistic evolutionists claim otherwise, saying that the record of change is slow, with gradual increases in cranial capacity, tool-making abilities, aquisition of controlled use of fire, and so forth. In a way, it seems odd that the simple claim that man has a special nature should be so controversial -- but that is the sticking point for evolutionary materialists, who insist that there is no special human nature, and that man is simply the end population stages of a gradual development of purely animal organisms over millions of year. To them, man is just a highly developed animal. To Christian philosophers, man is an essentially distinct natural philosophical species, possessing a spiritual soul, with intellect and will not shared by brute animals.
How is it possible to explain the physical record of gradual primate anatomical and artifact development while claiming that there is an Adam, who is the first true man, essentially superior to all of his predecessors? Most evolutionists declare that there could have been no "Adam."
Viewed purely as a material being, man does appear as merely the end product of billions of years of biological rearrangements of chemical constituents. When an atom of sodium and one of chlorine unite to form a molecule of salt, one can look at this union as merely the "hand-shaking" of two distinct atoms, the mere "donation" of one electron from the chlorine to the sodium atom. So, too, as chemical complexity increases over eons, organisms resulting from evolutionary mechanisms can be viewed as merely highly-complex "chemical soups" in a temporary state of equilibrium, but not as things in themselves, possessing some real unifying principle beyond the general laws of physics and chemistry which govern all material entities. In crude terms, it comes down to asking whether we are merely a more or less attractive-looking pile of atoms with a name attached, or are we really one being with a common human nature throughout. To save common sense, which tells us that we are real things, substantially one in nature throughout our entire bodily being, Christian philosophy maintains that an essential unifying principle, the substantial form, actualizes matter, specifying it as being of a stable human nature. This human nature is essentially distinct from and superior to the nature of subhuman primates and other lower animals. In man, the substantial form determines all the powers we possess, including those of intellect and free will, which latter set us apart from, and ontologically above, brute animals. This same substantial form (soul) determines that we are a person, spiritual in form and with personal immortality. Since we then possess a spiritual soul, and since spirit cannot come from matter, God alone can create each and every human spiritual soul.
Hence, the first human being created by God, whatever the circumstances, would be Adam. Since a being must be either spiritual in nature, or not, there is no possibility of gradual attainment of a spiritual soul. The first human being would be completely human, with all prior primates being merely subhuman, material organisms. Prior primates would have sense powers, but man alone would have the spiritual faculties of intellect and free will.
This scenario, as depicted by Christian philosophy, does not violate the data of natural science, because the possession of spiritual faculties does not mean that they must always be in act. We can detect their presence by finding signs of intellective activity in forms of special types of tool making or art or cultural rituals. But the absence of such signs does not assure us of the absence of intellect, since man can also engage in the same activities as mere animals and/or material signs of his intellective activity may be obliterated by the ravages of time. The fact that gradual improvement in tool making or other activities takes place over time does not prove that a radical line of demarcation is not present. At some point in time, true man became present. Before that he was not, and what we find are simply signs of complex sentient behaviors of lower animals, including subhuman primates.
The evidence of this line of demarcation lies in the same evidence Christian philosophers use to prove that man is essentially superior to brute animals today, that his soul is spiritual and theirs is not. If the distinction exists today, it must have begun to exist at some time in the past, since true man was not always in existence. Thus some first presence must have occurred, and the first human being having such faculties was therefore he who we call Adam.
Objections that not all men exhibit full intellective powers at all times -- or in some instances, not at all -- are not valid. The nature is stable in this type of being, whether he acts fully in accord with it or not. When we are sleeping or comatose, we may not be thinking or playing the piano, but we remain fully human. The nature belongs to the human natural species, whether it is fully operative at all times or any time at all. (This is the philosophical distinction between possession of an operative potency, or power, and its actuation. Actuation is not always possible, either because we are performing a contrary act or because of defect in the organs needed for operation, as in the case of brain disease or malformation.)
I realize that a materialist will have none of this, since he denies that man possesses any spiritual powers at all, and claims that all animal activity, including human, is basically dependent upon brain activity and other physically organic functions. I am not arguing that point here, since a materialist would deny all the basic presuppositions of the type of worldview in which the question of Adam and Eve arises anyway. What I am saying is that Christian philosophy provides a structure in which the belief in Adam and Eve makes sense, given the foundational system in which the question reasonably arises. That is, if you grant the existence of God and the spirituality of the human soul, then God must have created a first human being at some point in the evolution of earth's history -- and that first human being would be he who believers call Adam. Moreover, I am saying that the structure of Christian philosophy can reasonably adapt to the evidence of natural science which points to gradual development of behaviors, from the purely sensory to the clearly intellective. Materialists understandably read the same data entirely otherwise, but that reflects a radically distinct philosophical worldview from the one in which the question of Adam and Eve's literal existence would be expected to arise. Thus, for Christians, belief in a literal Adam and Eve is warranted in the sense (1) that it does not violate their general philosophical worldview, (2) that that worldview is not inconsistent with what we know of primate and human development over time, and (3) that the arguments for the human spiritual nature necessarily imply some first true human being, whom we call Adam.
II. Some theological thoughts about Adam and Eve: [Posts 237 and 238]
If I accept your claims about molecular biology, case closed. Adam and Eve do not exist. Worse yet, you have proven that they cannot exist!
Is that the end of the story? Not quite. Let us look at the overall picture we have developed on this thread.
Your worldview is now rather complete: You affirm that you are a sensist and a materialist. You affirm that you do not believe in a personal God, and reject any formal proofs for God's existence, in part, because there is no empirical way to verify His actual existence. You deny the existence of a spiritual, intellective soul in man. You deny the universal, transcendental validity of the principle of non-contradiction and all other metaphysical first principles. You describe yourself as a "pragmatic verificationist." You reject the validity of miracles and the theological claims of the Catholic Church. You insist that real contradictions exist at the subatomic level. And, of course, you maintain that the findings of molecular biology exclude any possibility that a single set of first parents for all mankind could have existed within the last six million years. Relevant to this thread, you conclude that scientific findings exclude the possibility of a literal Adam and Eve.
Your inference about Adam and Eve is understandable, given your firm commitment to natural science as your primary source of formalized information about the world, and your absence of any contravening theological or philosophical reasons not to enthrone that source above all others.
Not surprisingly, my view of reality differs radically from yours. On almost every point. Indeed, full exploration of the substance of these differences would require extensive study of major topics in natural science, epistemology, philosophy of nature, and metaphysics -- something that cannot be adequately done in a single 1000 posting thread (to put it mildly!). To return to our main theme, therefore, I am going to speak more in terms of outlines of positions, leaving it to the reader to investigate whether a particular line of argument may be fruitful to show that "belief" in Adam and Eve is "warranted." Given the diversity of our worldviews, it is to be expected that what one of us finds "warranted," the other may find totally "unwarranted." If I maintain that God's existence can be demonstrated, that the spirituality and immortality of the human soul can be demonstrated, that the principle of non-contradiction must be transcendentally valid, that some genuine miracles demonstrably occurred, and so forth, clearly I will assent to some truths -- even pertinent to the literal existence of Adam and Eve, which you will claim to be absurd and unwarranted.
You think theology is irrelevant to the question of whether Adam and Eve existed. But religious revelation is very relevant both in terms of providing sound reasons to believe what is taught, and in terms of the content of that teaching. I shall not reargue the nature or evidence for miracles which point clearly to Catholic belief. For those who wish to examine the number and quality of these miracles, consult the following: Raised from the Dead: True Stories of 400 Resurrection Miracles by Fr. Albert J. Hebert (Tan Books, 1986), Eucharistic Miracles by Joan Carroll Cruz (Tan Books, 1987), Mysteries Marvels Miracles: In the Lives of the Saints by Joan Carroll Cruz (Tan Books, 1997), and The Miracle of Lourdes by Ruth Cranston (Galilee Trade, 1988). The last includes fourteen recently documented cures updated by the Lourdes Medical Commission. (Original Popular Library edition, 1955)
Not surprisingly, these phenomena range from the historically obscure, doubtful, or poorly documented to the recent, scientifically well-documented, and theologically approved. Skeptics often use less certain cases to generalize to the rejection of all miracles, or offer philosophical arguments against their very possibility. That is why the detailed "before and after" records of the Lourdes Medical Commission offer critical scientific evidence. The Medical Commission is composed of distinguished physicians and scientists, operating independently of the Church. To suggest that its findings are not highly scientific is to apply the concept of "scientific" selectively. It is true that only some 67 cures have been approved by the Church, out of multiple times that number certified as beyond any natural explanation by the Medical Commission. But, to my knowledge, no one, including Bernadette and the "Lady," ever claimed that any miracles whatever would occur at Lourdes. Nor is God required to keep on performing them for our incredulity. The central and ongoing "miracle of Lourdes" is in the spiritual order of conversion and acceptance of God's will. The miracle of Fatima stands as history's most widely witnessed. Explanations of mass hallucinations or differing experiences ignore the fact that some 70,000 people witnessed an extraordinary event predicted by the children, "so that all may believe." Even O Seculo (a pro-government, anti-clerical, Lisbon paper) published an article the next day by its atheistic director, Avelino de Almeida, entitled, "Terrifying Event! How The Sun Danced In The Sky Of Fatima." No astronomers confirmed this event. Rather, it was a massive, varying, religious-content apparition, whose physically "objective" component was the sudden drying of 70,000 witnesses whose woolen clothing had been soaked in drenching rain which suddenly ended just before the apparition commenced.
While no one can force anyone to believe anything, Catholics may rightly "warrant their belief" in the Catholic Church based on this continuous history of miracles, beginning with the Resurrection itself -- miracles largely filled with Catholic specificity. Moreover, this massive evidence serves only to complement the often ignored theological science of apologetics, which is the rational defense of the Catholic Church.
And what does the Catholic Church teach about a literal Adam and Eve? The dogma of Original Sin teaches that Adam lost sanctity and justice by transgressing the divine commandment, that this single sin is transmitted to all his posterity by descent -- not by imitation, and that it dwells in every human being -- transmitted by the natural act of generation. (Denzinger 789-791) Pius XII makes clear in Humani generis that this is "a sin actually committed by an individual Adam." (H.G. #37) Catholic teaching is thus clear about the actual existence of Adam as an individual human being. And since Adam transmitted original sin by the natural act of generation, it necessarily follows that he did so with the co-operation of a female spouse, Eve. Hence, belief in a literal Adam and Eve is warranted.
Further, the miracles of Lourdes arise in a context which points specifically to Adam's existence, since St. Bernadette Soubirous told authorities that the Lady who appeared to her in 1858 said that she was the "Immaculate Conception." The dogma of the Immaculate Conception had been defined just four years earlier in 1854, and declares that the Blessed Virgin Mary was conceived free from original sin, the sin committed by Adam. Hence, Lourdes specifically, though indirectly, confirms the literal existence of Adam and Eve.
As to the question of theological polygenism, Pius XII teaches that Catholics are not free to uphold polygenism, because "it is in no way apparent how such an opinion can be reconciled with that which the sources of revealed truth and the documents of the Teaching Authority of the Church propose with regard to original sin, which proceeds from a sin actually committed by an individual Adam and which, through generation, is passed on to all and is in everyone as his own." (H.G. #37) Clearly, the Holy Father was aware of the complexity of the relationship between polygenism and the implications of original sin -- and thus spoke about it in a manner somewhat more carefully nuanced than he did in reference to his prior comments about the freedom of theological speculation regarding evolutionary theory and human origins. Theological monogenism may well eventually become firm teaching, but that simply is not presently the case. What this means is that it would presently constitute theological dissent for a Catholic to advocate polygenism. Somewhat paradoxically, at this same time, it appears that one cannot absolutely declare that a proof of the reality of polygenism is equivalent to a disproof of the Catholic religion, and of its teachings about Adam and Eve. All this is not an attempt to avoid direct confrontation over the scientific evidence for or against a relatively recent single pair of first parents for all mankind. Rather, this is simply an accurate statement of the present theological situation.
Since belief in the Catholic Church is warranted by objective evidence, and since the Catholic Church teaches that Adam and Eve existed, belief in a literal Adam and Eve is warranted. One must never forget here that we are talking about warrant for "belief," not a direct and absolute demonstration of two human beings hidden deeply in the recesses of time, as Teilhard de Chardin says, "...positively ungraspable, unrevealable to our eyes at no matter what magnification." [The Phenomenon of Man (Harper & Brothers Publishers, 1959), p 185, note.] The burden of proof remains upon those who would declare Adam and Eve could never have existed.
III. Some thoughts about natural science and Adam and Eve: [Posts 265 and 266]
Regarding posts 220, 221, 222, and 223:
In these posts, you have powerfully defended your thesis that there have been no bottlenecks of just two people in millions of years. A good example of the kind of argument you offer is the following: "... the assertion that the molecular data is consistent with a bottleneck of two is just that - an assertion completely unsupported by the evidence - in fact denied by it because the DRB1 data on its own logically precludes such an extreme bottleneck and that is before we consider the size of a real population capable of sustaining the heterozygosity, microsatellite and LD data that we see. A bottleneck of two would result in far more homozygosity than we see as neutral alleles drift to extinction or fixation rapidly in a tiny population. ... To prove me wrong, all you have to do is to cite a reference to a paper which sets out the reasoning for considering a bottleneck of two as a possibility."
I am going to concur with your claim that "...there is remarkable consistency across multiple methods of estimating palaeo-demography, and there is unanimity that the population ancestral to humans never passed through a bottleneck of two individuals...."
Nonetheless, careful reading of your posts suggests to me that your conclusion about the scientific concensus is not based on the question of effective population size, but rather on other aspects of specific genes. Regarding effective population size, you affirm that in the last million years the concensus has been that it has been about 10,000, while Tenesa puts it at 7,500 in 2007. The important point of this is that when the genome in general is considered, the long-term effective population size of either 7,500 or 10,000 is consistent with the possibility of a bottleneck of just two individuals within the past 10,000 generations or so. For example, in Wen-Hsiung Li's widely-used textbook, Molecular Evolution, he states (pp. 46-47):
"The effective population size can also be much reduced due to long-term variations in the population size, which in turn are caused by such factors as environmental catastrophes, cyclical modes of reproduction, and local extinction and recolonization events. For example, the long-term effective population size in a species for a period of n generations is given by:
Ne = n/(1/N1 + 1/N2 + ... + !/Nn)
where Ni is the population size of the ith generation. In other words, Ne equals the harmonic mean of the Ni values, and consequently it is close to the smallest value of Ni than to the largest one. Similarly if a population goes through a bottleneck, the effective population size is greatly reduced."
My biology contacts tell me that if one uses the formula above for the effective population size, then a population which starts with 2 individuals and expands within ten generations to 10,000 individuals and then remained constant would have an effective population size of about 6,000. If it expanded quickly from 2 to 100,000, the effective population size would be about 12,000. Thus, with the uncertainties involved, a bottleneck of two is easily compatible with the effective population size of about 10,000 today.
You write: "Furthermore, there isn't the slightest shred of evidence to support the notion that the human population could or did expand at more than 100% per generation over ten generations in palaeolithic times." We must always recall that absence of evidence is not the same thing as evidence of absence. I can tell you easily how the human population could have expanded more than 100% per generation over ten generations. It is simple. Start with Adam and Eve and let them have just six children, three boys and three girls. (Incest was not an initial problem.) These three pairs mate producing each six more children, equally divided by sex. That give us 18 in the next generation. These then mate to so that 9 pairs x 6 children equals 54 more people. Each generation is producing 300% more than itself! The math runs then for sequential generations: 6, 18, 54, 162, 486, 1458, 4374, 13122! Oops! That is only EIGHT generations to exceed 10,000 persons! But how could this be so perfectly "arranged" in nature? I am not saying this exact scenario occurred, but merely showing that such rapid population growth is not beyond the range of possibilities that may exist in this amazing world.
From this perspective, the effective population size of 10,000 in the last million years easily could allow a bottleneck of just two individuals, Adam and Eve, quickly propagating 10,000 individuals in just ten generations or so.
So, why do your experts insist the population never could have been smaller than, say, one thousand?
Now here is where I am going to partly agree with you. You have built a powerful case to prove that other specific genes in the genome indicate in various ways that a bottleneck smaller than one thousand appears impossible. The problem with that is that specific genes might behave in unusual ways, and so are less reliable. Or, we may discover something about them we did not previously know. Consider the case of Ayala's 1994 claims about a specific behavior in the genes. In 2006, Shiina et al., contradict his thesis about massive flow of alleles from one species to the next:
"This result finally puts the MHC in line with the bulk of population and evolutionary genetics data which firmly conclude that a narrow bottleneck has occurred at the origin of our species (Cann et al. 1987; Hammer 1995), a fact inconsistent with massive flow of alleles from one species to the next as required by the transspecies postulate (Ayala et al. 1994)." Takashi Shiina, et al. (2006) Rapid Evolution of Major Histocompatibility Complex Class I Genes in Primates Generates New Disease Alleles in Humans via Hitchhiking Diversity. Genetics, 173, 1555-1570.
The only inference I am here drawing from this more recent article is that it appears Ayala was wrong in 1994 about his "transspecies postulate." Scientists can make mistakes, even in molecular biology. If you are making the argument that a bottleneck of two is impossible based on particular genes, that may be very impressive in terms of what we presently know about the human genome. Still, that is a very different argument than the one based on effective population size, whose conventional estimate for the last million years is quite consistent with the possibility of a bottleneck of just two. Even if we grant the force of your present arguments (and I am confident you will inundate me with much more supporting evidence and "absolute certitudes"), the difficulty is that we may find out something "surprising" about gene behavior in the future -- just as we did in the case of Ayala's 1994 claim. Moreover, there is an inherent uncertainty "built into" any attempt to determine absolute certitudes about specific distant past events based solely upon microscopic analysis of present evidence, especially when much of the science is of very recent vintage and entails many assumptions and estimates. Unlike Catholic dogma, this is not the stuff of divine revelation.
That is why in my book, Origin of the Human Species (Sapientia Press, 2003), first published in 2001, I conceded that a bottleneck of two would be considered by scientists to be improbable. Nonetheless, consider the improbability of the Big Bang's expansion rate being so incredibly balanced that it avoided the outcome that life that would never have occurred had it been either the slightest bit greater or smaller. If I were viewing the situation as you do, without factoring in the ability of God to create the actual beginning, then I might consider that a bottleneck of two could not take place. But, I believe in (and can demonstrate philosophically) the existence of a personal God who is quite capable of exercising providence over the whole of His creation -- vanquishing improbabilities, and allowing for rapid population growth from two first parents
It has been the history of natural science to think it has had "everything figured out." Despite the supreme confidence you exhibit in the most recent findings of molecular biology, one must balance this with some awareness of the radical tentativeness of specific theories and paradigms, even if you believe that science makes general progress. On an even larger scale, consider the overconfident mentality of scientists at the end of the 19th Century who thought that Newtonian science had triumphed over all -- just before relativity theory and quantum mechanics radically undercut those expectations.
Over time, the prospects for Adam and Eve have improved on the large scale. The consensus has moved away from the idea that true humans evolved in separate parts of the globe simultaneously, which would have grossly violated the thesis of a single pair of first parents: Wolpoff's multiregional hypothesis has given ground to more general acceptance of the single-source "out of Africa" hypothesis. And, rather than having constant expansion of an ever-growing primate population dating too far into the past for Adam and Eve, the effective population size estimates have actually dropped in size, from the 100,000 estimate for the last 30 million years to just 10,000, or even less, for the last million years -- allowing at least the mathematical possibility of a bottleneck of two since the middle Pleistocene period. Potential future uncertainties cannot be ruled out at this time unless one possesses a crystal ball.As I have indicated in other posts, although there remain some somewhat unsettled areas in the theological, philosophical, and natural scientific analyses regarding this matter, I maintain that it is reasonable for 21st Century, educated people to believe in a literal Adam and Eve.
Origin of the Human Species (book from amazon)
Origin of the Human Species (website)
"Must Human Evolution Contradict Genesis?"
"Did Darwin Prove Genesis a Fairy Tale?"
"Books on Evolution"
"A Philosophical Critical Analysis of Recent Ape-Language Studies" (+ Part II)