What sort of revision does scientific research call for on the Catholic doctrine of the fall?

John Farrell wrote about the problem that modern theories of polygenism pose to the Christian doctrine of the fall. The article was picked up by Bill Vallicella and Mike Liccione. Any time one mentions this controversy, the discussion threatens to explode in ten different directions at once, so I’ll cut to what I take to be the final answer, which I see as having three parts: (a) No revision of doctrine is necessary (b) defending the old doctrine does not require dialectical backflips and hair-splitting; and (c) The revision that is called for is not a revision in doctrine but a move from the simplest set of facts congruent with a doctrine to a less simple set of facts congruent with the same doctrine. The difference here is crucial: a change in doctrine would be like moving from evolution to creationism; a change in facts congruent with one doctrine would be like moving from incremental to macro evolution or from Paley’s design theory to Dembski’s.

The best science is that there was never a time when there was only one generating couple on earth. Right off the bat, there are difficulties in bringing this finding into conflict with the Scriptural text, since Cain finds people outside of Eden as soon as he is cast out of it. We can, of course, adopt the ancient Rabbinical commentary on this that Cain in fact finds only his brothers and sisters, though this interpretation is perhaps not the simplest one, and it also creates its own problems (What are his siblings doing outside of Eden anyway? There appear to be a good many persons with a good deal of technical skill out there.) Even after we take into account the mythical character of the story, it is not clear that the intention of the author was to have Adam enter into a world without human beings. It is true that Eve is called “the mother of all the living”, but in everyday language we mean more than one thing by this, which should become clear in a moment.

The difficulties in parsing out the Scriptural narrative make us cast about for a more unequivocal statement, and all sides agree that we find it in Humani Generis:

[T]he faithful cannot embrace that opinion which maintains that either after Adam there existed on this earth true men who did not take their origin through natural generation from him as from the first parent of all, or that Adam represents a certain number of first parents.

Usually, authors include the next sentence that gives the reason why one can’t hold either position, but this skips too quickly over what exactly Pius is condemning. Just look at the words of the first condemned opinion:

After Adam there existed on this earth true men who did not take their origin through natural generation from him as from the first parent of all.

This is a statement about the world after Adam. But when something happens over a period of time (as opposed to being a single event) to speak of what happened after it is usually to speak of what happened after it ended not after it began. For example, if you say “after Marcus Aurelius the persecution of Christians ended”, you are talking about what happened after Marcus died. After can also mean “after the beginning”, as in “After Constantine, the Christians received more rights”, but even this is ambiguous, since one is really trying to speak of something that happened during Constantine’s reign and not necessarily at its inception.

Why is this significant? Take two hypotheses:

1.) There were no men anywhere on earth. Then Adam was created. Then all later persons descend from him.

2.) There are men on earth. Then Adam was created. By the time he died, all living persons had him as an ancestor.

Pius’s condemnation doesn’t apply to either hypothesis. Said another way, if we want to decide between these hypotheses – even as faithful Catholics – we are going to appeal to something other than Pius’s condemnation. All other things being equal, of course, the first hypothesis is the simpler one and so is the reasonable one to adopt, and for the Church Fathers and almost every scriptural commentator up until very recently, this ceteris paribus clause still had force. There was, however, always reasons to question it: one  could have always wondered  where Cain’s wives and male citizens came from (as the Clarence Darrow character does in Inherit The Wind), or he could fall across a finding in physical science that the human population was always greater than 1. Either argument gives a reason to abandon the simplest hypothesis. The need to “revise theology” is therefore not a need to move from one doctrine to another, but from a simpler explanation of the doctrine to a less simple explanation. By “simple” I mean more or less the doctrine one would form at first glance, all other things being equal. Again, the motion is not from one doctrine to another but from a simpler to a less simple set of facts under the same doctrine. We are not moving from monogenism to polygenism, but from a simpler account of monogenism (all after Adam descended from him, and there were no others) to a more complex monogenism (all after Adam descended from Adam, but there were others.)



  1. TheOFloinn said,

    September 2, 2011 at 9:33 am

    I wish I could be as concise as you.

    I’ve always figured that there was an equivocation on “one.” That all my cousins and second cousins are descended from one great-grandfather does not preclude our descents from other great-grandfathers, and in fact not all the same others. So that there is one man from whom all men are descended does not imply that all men are descended from [only] one man, since “one [out of many]” is not equivalent to “[only] one.” As you said, Cain had no problem finding a wife, building a city, etc.

    • GeekLady said,

      September 2, 2011 at 11:02 am

      For what it’s worth, I thought yours was more comprehensible from the scientific perspective.

      I love this blog, but I usually need to read Mr. Chastek’s essays several times before I either understand or give up. Not his fault, of course.

  2. Brandon said,

    September 2, 2011 at 9:39 am

    In a sense there may be an analogy to the way science leads to revision of fundamental common sense beliefs. Scientific understanding of why the sky is blue may come up with truly startling results; you could talk about this as “revising our beliefs about the blueness of the sky,” but what’s really going on is that the blueness of the sky is what it always was: we’ve just gone from a simpler, prima facia account of the blueness of the sky to a more complicated, sometimes surprising, account of the blueness of the sky.

  3. September 2, 2011 at 11:36 am

    Am I over-doing thing in thinking that we can also stretch the meaning of “after” a bit here?

    As receivers of the Old Testament, we’re all “after Adam” as in being in a post-Adamic world. It seems to me that we would certainly hold that at all point throughout OT and NT history, all humans are naturally descended from Adam. I’m not sure one would have to hold that by the time of Adam’s death all humans still alive were descended from him.

  4. John Farrell said,

    September 2, 2011 at 12:52 pm

    By the time he died, all living persons had him as an ancestor. James, I think this is the part you would have a hard time selling in plain English to a genomist. What exactly do you mean by ancestor, if it is not to be understood in a physical, genetic sense?

    • TheOFloinn said,

      September 2, 2011 at 2:06 pm

      Probably in the same way that the Flynns in this area all have Daniel Joseph Flynn as a common ancestor, even though we have other ancestors. All other male Flynns had daughters or no issue so their lines are no longer Flynns.

      I don’t think it needs to be fact from the very moment of Adam’s death, but it is not at all unreasonable that one great…..great grandparent might wind up on everyone’s family tree. From a statistical point of view, it’s fairly likely.

    • BenYachov said,

      September 7, 2011 at 4:11 am

      Are you serious John? It is a brute fact I (like everybody else) have ancestors of whom I have practically none of their genetic material but I did descend from them physically. They are my True Forefathers.

      Scripture teaches Fatherhood is a spiritual thing not so much physical. After all God could turn the stones into “Sons of Abraham” .

  5. G. Kyle Essary said,

    September 2, 2011 at 7:02 pm

    As an evangelical, I don’t fit the mold of the discussion, but the issues that I don’t believe evangelicals have adequately addressed are these:

    1. What does it mean to say “Adam was the first man?”
    2. Are we referring to his biological category as homo sapien?
    3. Are we referring to his spiritual category as something like a homo divinus in that this particular homo sapien was the initial creature made in God’s image?
    4. Are we referring to his spiritual capabilities to be in relation to God?
    5. Are we referring to the literary character (historical or not) in the history of salvation as presented in Scripture.

    It seems to me that many of the difficulties arise from equivocating over the meaning of the word, “man.”

  6. G. Kyle Essary said,

    September 2, 2011 at 7:03 pm

    I forgot to click “follow-up comments”

  7. September 3, 2011 at 11:38 am

    To begin with, I second John Farrell’s remark above. I don’t think we need worry about Bill Vallicella’s critique of Farrell’s original post; I’ll explain why on my own blog.

    • NS said,

      September 3, 2011 at 1:36 pm

      What about TheOFloinn’s reply to it? I think once one speculates that Adam and Eve were not alone in the sense that there were others around who they were interfertile with, and that A&E or their offspring were able to interbreed with those others, most of the suggestions that there’s some scientific problem with Adam and Eve drop away immediately.

      One problem I have with this conversation is that I get the impression that there’s a false dichotomy set up where either Adam and Eve were created out of nothing and that’s where all of humanity comes from or there was no historical fall. You yourself seem to think otherwise given your blog entries on this subject. Farrell, I’m not so sure of – he seemed to be outright denying that there ever was a Fall, period.

      • September 3, 2011 at 1:43 pm

        Well, John can speak for himself. I know he liked my most recent post on this subject, and I do affirm that a Fall actually occurred. I think he just doubts that a historical Fall can or ought to be tied to a “single great-grandfather,” in the genetic sense, of everybody begotten after “Adam.” I doubt it too, although I don’t rule it out.

  8. John Farrell said,

    September 4, 2011 at 3:01 am

    I too am not arguing The Fall has to be re-thought (as in , discarded); but I don’t have Mike Flynn’s confidence that we can claim any one ‘Adam’ as a common ancestor. Especially now, as the Nature article explains, that it becomes ever clearer some–but not all of the human race–shows the genetic evidence of interbreeding with at least two if not more extinct lineages.

    • TheOFloinn said,

      September 4, 2011 at 11:52 am

      That I have many ancestors does not preclude that I (and all my relatives) have one common ancestor. Many other families have married into the progeny of John Thomas Flynn, as evidenced by the other family names that crop up among my cousins.

      My point was that the genetics of many ancestors does not preclude the existence of one ancestor. We don’t need the word “only.”

      • John Farrell said,

        September 5, 2011 at 11:47 am

        Yes. My worry, though, is that the Church may believe we need the word “only” as Br. Gabriel is suggesting.

  9. Peter said,

    September 4, 2011 at 4:11 am

    But interbreeding is exactly the issue. The argument is that these various lineages ultimately get mixed with Adam’s progeny and partake of his state. So within a given amount of time, everyone alive has some Adam in him, and thus are truly his descendents, if only partially. How does the evidence of multiple lineages refute this interpretation?

  10. John Farrell said,

    September 4, 2011 at 5:34 am

    Yes, but James offered this starting hyothesis, By the time he died, all living persons had him as an ancestor.

    No matter where you embed this Adam branch, among others, I don’t see how you can avoid implying that Adam must have lived thousands, not hundreds, of years for his ancestry to have outlasted his contemporaries.

    • September 5, 2011 at 7:26 pm


      Been out of town all weekend.

      My post here is meant to clarify hypotheses that might be modified in the light of some sorts of evidence. If, for example, one has findings that there are multiple genetic lines for human beings, or that all human genetic information could not be derived from a single person, then I think a plain reading of the relevant texts does not lead one to take this as evidence against monogenism in the way this must be taken in Christian doctrine. You are not objecting to this, but only disputing the point that Adam could have lived long enough to be an ancestor to all by his death. Perhaps. But a thousands-years-old-Adam-claim is not in conflict with any scientific finding I am aware of, and it is not any harder or easier to believe than the actual length of life that the Scriptures attribute to Adam.

  11. Peter said,

    September 4, 2011 at 8:46 am

    “By the time he died” is a reading of “existed after Adam”. So, place it later if you want.

  12. September 4, 2011 at 8:47 pm

    Something that is not considered in this post is one aspect that is essential to the understanding of any document. We must try to understand the mind of the Law Giver. It is insufficient to take the words of the text and apply them as we like. Rather, we must interpret the text in light of what was intended by the Holy Father. This will require more work. However, given the debates of the time it seems obvious that the Holy Father was intending to communicate simply that Adam and Eve were the first parents of all beings baring the name Human. There were no men before Adam and there were no men who existed contemporaniously with Adam save for his natural progeny.

    The importance of this is discovered in the text of Aquinas (and others) when they noted that Adam is a universal equivocal cause of all humanity. For this to be the case then Adam must be the true father of all humanity (this cannot be simply through the intermingiling of bloodlines). This is essential to our understanding of Original Sin. Original Sin is passed completly to each generation through generation. If there were other humans about then there would have been a time when some humans were a mixture of those with Original Sin and without Original Sin. However, this proposition is absurd because all men have Original Sin fully, not partially.

    Further, Adam could not be a Universal Equivocal Cause if he were not the highest of the genus of Man. Because of these simply causal realities it is necessary to reject the possibility of other humans existing apart from Adam’s direct lineage or we must reject our doctrine on the transmission of Original Sin. Since we cannot to the latter then we must reject the former.

  13. Brandon said,

    September 5, 2011 at 6:24 am

    The importance of this is discovered in the text of Aquinas (and others) when they noted that Adam is a universal equivocal cause of all humanity. For this to be the case then Adam must be the true father of all humanity (this cannot be simply through the intermingiling of bloodlines)….Further, Adam could not be a Universal Equivocal Cause if he were not the highest of the genus of Man.

    I’m not sure I follow this; if Adam is universal equivocal cause of humanity, it can’t be by generation; ordinary human generation is univocal causation, not equivocal causation. And if Adam is the universal equivocal cause of all humanity, he would no more have to be in the genus of Man than the sun has to be in the genus of Man — the sun is a universal equivocal cause of human beings, and, indeed, all life. Do you have a specific passage in mind?

    • Peter said,

      September 5, 2011 at 8:43 am

      Adam could not be a Universal Equivocal Cause if he were not the highest of the genus of Man.

      I have been trying to understand this as well. For the same difficulty you mention would apply to God as equivocal cause too:

      (SCG 1.29): “Effects that fall short of their causes do not agree with them in name and nature. Yet, some likeness must be found between them, since it belongs to the nature of action that an agent produce its like, since each thing acts according as it is in act. The form of an effect, therefore, is certainly found in some measure in a transcending cause, but according to another mode and another way. For this reason the cause is called an equivocal cause. Thus, the sun causes heat among these sublunary bodies by acting according as it is in act. […] So, too, God gave things all their perfections and thereby is both like and unlike all of them.”

      And again (ST I q. 4, a. 3, co.): “First, because whatever perfection exists in an effect must be found in the effective cause: either in the same formality, if it is a univocal agent–as when man reproduces man; or in a more eminent degree, if it is an equivocal agent–thus in the sun is the likeness of whatever is generated by the sun’s power. […] Since therefore God is the first effective cause of things, the perfections of all things must pre-exist in God in a more eminent way….”

      So if an equivocal cause had to be in the genus of what it causes, God would have to be in the genera of all things.

  14. September 5, 2011 at 10:56 am

    The distinction can be found in that God is not material and thus transcends all genus and is himself not in a genus. This transcendence allows for God to be equally the cause of all things in esse and in fieri. Adam is material but the first of his genus. This allows for him to be a universal equivocal cause of all men. All human generation after Adam (because there can be no other primogenitor) is in the mode of univocal causality. See Aquinas on the transmission of Original Sin: it will help clarify my point.

    • Brandon said,

      September 5, 2011 at 11:09 am

      Certainly an equivocal cause can be in the same genus as its effect, but I don’t find that this helps much in clarifying your statement about Adam as highest in the genus. Likewise, I can’t find anything in Aquinas’s account of the transmission of original sin that helps me make sense of your suggestion that Adam as universal equivocal cause is the key to the answer. Is there a passage in which Aquinas explicitly calls Adam the universal equivocal cause of all humanity? What passage in Aquinas’s account of the transmission of original sin do you have in mind?

      • September 5, 2011 at 5:16 pm

        Let me clarify. There are few things in my mind concerning this issue. What I mean by Adam being the highest in the genus of man is that Adam is the Universal Equivocal Cause of human nature. Fr. John Quinn in the Thomist (42 no. 1) investigates this aspect of the Physics underlying the thought of Aquinas. His article is directed specifically the Tertia Via but it continues to apply as a principle of the Physical world as Aquinas understand it. One place to reflect upon this is in ST I q. 13 a. 5 ad 1.

        With reference to Adam as one such Universal Equivocal Cause we can look at ST I-II q. 82 a. 2 c. where Aquinas says, “in one man original sin is one in number; and in all men, it is one in proportion, i.e., in relation to its first principle.” Also, in ST I-II q. 81 a. 1 c. where he says, “all men born of Adam may be considered as one man, inasmuch as they have one common nature, which they received from their first parents.”

      • September 6, 2011 at 9:16 am

        Hi, Br. Gabriel,

        I don’t really see how any of these passages (ST 1.13.5 ad 1 or ST 2-1.81 or 2-1.82) suggests that Adam is an equivocal cause of human nature. Rather, the latter passages strongly suggest that Adam is a cause, with respect to original sin, as moving his descendants through generation; but generation is univocal causation, indeed, one of the paradigmatic instances of univocal causation. For Adam to be an equivocal cause of human nature, it seems that he would have to be of a higher species than human.

      • Peter said,

        September 6, 2011 at 11:56 am

        The article referenced above can be read here. Unfortunately, it didn’t clarify this issue for me.

      • September 6, 2011 at 12:10 pm

        The striking passage is where Aquinas notes that the nature of men is given by Adam in 81, 1, c. This little detail indicates that Aquinas is thinking of Adam as a Universal Equivocal Cause because Universal Equivocal Causes are causes of natures, Univocal Causes are not causes of natures. To use the example of Aquinas as a negative example, no single horse or the sum total of all horses cause horse nature. Likewise, normal human generation is the type of univocal causality, however, the Primogenitor of a species, seems, according to this account to be a cause of the nature of the species.

        I’m not going to make the claim that I understand exactly why this is. Just like everyone else who studies Aquinas today I lack the rigorous understanding of Aristotle’s Physics that I would need to understand exactly why this is the case for Aquinas. Yet, if Adam is the cause of human nature in the way that Aquinas establishes then Adam is to be considered as a Universal Equivocal Cause.

      • September 7, 2011 at 7:38 pm


        Would it be unacceptable to say that Adam, by the act of sinning, changed our nature (“By one man sin entered the world”) according to which it is fallen, FROM the perfect state of human nature he had prior to sin, thus acting as the equivocal cause of the fallen nature (by being the cause of it in himself, who was previously unfallen) and thereby (semi-simultaneously, actually, in that at that moment if he procreated we would have it) the univocal cause of the nature in procreation?

        We miss you back at home.

      • September 8, 2011 at 8:30 am

        Thank you Tom.

        I don’t know how he could be an UEC of one aspect of our Nature without being the UEC of the whole. I think that if it is correct to say that Adam is a UEC of human by his status of the Primogenitor then he becomes also transmitter of human nature by means of Univocal Causality. It seems that Adam can be considered both ways under different ratios. Put another way he is a cause of our nature Equivocally and the transmitter of our nature Univocally.

        The question that must be asked, then, is can an entity be both a Univocal Cause and and Universal Equivocal Cause of the same thing, and if so, how?

      • September 8, 2011 at 10:46 am

        Let’s look at the graph!

        God creates Adam ex nihilo; this is His primary equivocal causality.

        Adam is perfect; if he begat at this time, man begets man, that’s univocal if I am not mistaken about how we’re thinking of this.

        Adam sins; nature falls in him; perfect man having a perfect nature becomes imperfect man having an imperfect nature; that’s equivocal, and the equivocal cause of the change of nature in man begotten of Adam; thus it’s both equivocal causality of Adam’s fallen nature in himself, and universal equivocal causality of the whole which is held in his power of begetting, no?

        Adam begets another fallen man; that’s univocal causality after the Fall, is it not?

        So Adam would be both the univocal cause of his children, and the equivocal cause of the nature in them as fallen prior to their being begotten. How is this incorrect?

    • September 9, 2011 at 8:48 am


      With your fuller explication of the issue I think you are right on the money. The distinction that you put forward between being the univocal cause of the children qua children and the equivocal cause of the human nature qua human nature seem, to me, to be what is at stake here.

      What I (and I suppose Brandon) can’t get my mind around is how Adam would be unique in this. It is simply because he is the Primogenitor? If this is the reason, then why? Would this be the same for the first Horse, cow, dodo bird? What is the metaphysical difference between the first of a species and those that follow? As we know, no subsequent human person can be a Universal Equivocal Cause of the human nature just as no horse or the sum total of all horses can be the cause of the horse nature. Yet, what seems to be offered is that this is not the case for the first of any given species. Also, Adam is a human person, and if he is the UEC of the nature of the rest of humanity he cannot the cause of his own human nature. This goes to an earlier comment which suggests that the cause of the nature must be above that species.

      Is it simply that God is the cause of Adam’s nature, because of the special direct creation of Adam, then Adam becomes a UEC of the nature of all subsequent human persons? I can see this as a possibility because Adam would be the first man and he would be necessary for all subsequent men. In this way, Adam becomes a sort of contingent necessary being with respect of the rest of humanity. The issue is still unclear to me.

  15. Brandon said,

    September 5, 2011 at 11:45 am

    Re-reading the relevant passage of Humani Generis, I am struck by three things. The passage is this:

    “When, however, there is question of another conjectural opinion, namely polygenism, the children of the Church by no means enjoy such liberty. For the faithful cannot embrace that opinion which maintains that either after Adam there existed on this earth true men who did not take their origin through natural generation from him as from the first parent of all, or that Adam represents a certain number of first parents. Now 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.”

    The three things that strike me are “conjectural opinion,” “cannot embrace,” and “it is in no way apparent how such an opinion can be reconciled” (‘coniecturali opinione’, ‘non…amplecti possunt’, ‘nequaquam appareat quomodo huiusmodi sententia componi queat’ in the Latin). This, taken on its own, suggests three approaches for someone who thinks that the scientific evidence strongly suggests some kind of polygenism.

    (1) Establish that it is not merely a conjectural opinion, i.e., establish beyond serious doubt or likelihood of correction that it is true. (The Latin word here translated as ‘conjectural’ is arguably broader than the English word ‘conjectural’, which suggests guesswork; ‘probable’ would perhaps be at least as good a translation.) That the ‘conjectural’ part is not a mere incidental aside is clear from the context, which has been placing a big emphasis on the attitude to take when things are not established as certain. This then establishes the necessary task of showing how this does not require one to embrace what the faithful cannot embrace and showing how this can be reconciled to the doctrine of original sin.
    (2) Make use of the theory but without embracing it: i.e., be benevolently agnostic about its actual truth so as to take it instrumentally as a useful heuristic for further inquiry without committing to it. On this approach, it remains conjectural, its apparent nonreconcilability remains, but it can be treated as a useful calculating device (so to speak) until a better theory comes along.
    (3) Give an account in which it becomes clear how it can be reconciled with what the sources of revealed truth and the documents of the Magisterium propose about original sin. This makes any mere probability irrelevant and would show that it does not fall within the class of doctrines that the faithful cannot embrace.

    Of course, one could also just stick to one’s guns and insist that the scientific claim is wrong regardless of appearances. The problem is that there are, and in many cases have been, cases in which each one of these four approaches is the right approach while the others lead to a dead end.

    • TheOFloinn said,

      September 5, 2011 at 2:23 pm

      The fourth thing, that strikes me, is the expression “true men.” That all true men, i.e., all those hominids possessing intellect and free will, are descended from Adam is a different proposition from the one that might insist that all bodily hominids are. Intellect does not fossilize. Hominid bones do.

      It is also difficult to conceive, should biological mutation be relevant, how the same “sapient” mutation would occur all at once in multiple hominids. The way a gene usually spreads is that it appears once and then is found in the children and so on.

      After all, if all true men are descended from Adam, then they are all descended from Adam’s daddy, too. But if Adam’s daddy was a hominid lacking in a rational soul, that is of no consequence.

      • September 5, 2011 at 5:25 pm

        In most works that I have reviewed it is this use of “true man” that provides the greatest “wiggle room.” However, I think that it may be important to reject a theory of “emerging rationality”. The problem is that rationality is essential to the definition of the species of man. If we hold to an “emerging rationality” theory then we will fall into the trap of assenting to junk science, i.e., evolutionary theories that posit that man came from some other species, even a primate. However, there are currently no observed examples if “species jumping”. It would be foolish to construct a possible theological/philosophical anthropology that is contingent upon a theory without any observed phenomenon to support it.

        I also think that one of the things that Catholics are bound to assent to is the direct creation of Adam by God. I’m not to sure about this but I do think that it is at least a certain opinion. At the least it should be considered part of the Ordinary Magisterium on account of the understanding of the Church Fathers with respect to Adam’s creation.

  16. The OFloinn said,

    September 5, 2011 at 5:34 pm

    Not saying “emerging rationality.” That power is either present even a little bit or it is not present at all. But if we have a population of hominids — Adam, Bob, Carol, Ted, Alice,….– as the clay, what stops God from breathing a rational soul into Adam, and having his progeny eventually supplant the remaining hominids? “Species, also, that are new, if any such appear, existed beforehand in various active powers; so that animals, and perhaps even new species of animals, are produced by putrefaction by the power which the stars and elements received at the beginning.” The no poofing rule.

    • September 5, 2011 at 5:59 pm

      The difficulty lies in the area of species. Rationality is the defining characteristic of the human species. Any creature that does not have this faculty in their nature is not part of the human species. Breeding between such a hypothetical species and man would be analogous to man breeding with an ape or a horse.

      It is true that such a breeding pattern could have taken place. However, why speculate about a hypothetical state of affairs without any solid empirical evidence for that state of affairs. Rather, we should simply begin with what we know and see if we can account for the theological position as it has always been understood.

      We should always remember that to be a good theologian means that we begin from the position of faith. I believe that this means that we must work to justify the traditional understanding of a proposition related to the faith. Then, if we cannot then we must begin to reexamine our understanding of the proposition. I don’t think that the issue at hand has yet come to the point of us needing to reevaluate our traditional understanding of the doctrine.

    • September 6, 2011 at 9:15 am

      I agree that it’s complicated – there are theological truths that cannot change, but it is not always obvious what they are; there are scientific hypotheses that can change, but it’s not obvious exactly what those are. That’s why I’m framing the dispute here as a matter of hypothesis. I think it’s less a matter of trying to figure out what happened as of setting out options that have various grades of plausibility and reasonableness, and which illumine some things while, on the other hand, calling us to make various difficult calls.

  17. Brandon said,

    September 6, 2011 at 1:46 pm

    It occurs to me in re-reading some of the comments that one thing we are repeatedly not being careful enough about (although Mike essentially raised it) is avoiding the danger of equivocation between biological meanings (there are several, and some of them are very distinctive and technical) and the scholastic meaning of the term ‘species’ (and other terms, too, of course). Obviously any scientific evidence will be for biological senses of the terms and not, for instance, for metaphysical or moral senses of it; and obviously any comments the Church makes on the subject will be for the later. There would be no issue at all except that the two kinds of senses aren’t necessarily unrelated. All confusions on this subject are confusions about this relation between the kinds of senses, and all the difficulties are difficulties in understanding how they are related. That is really the one and only issue here.

    We see part of the problem in that according to one common (but not the only) biological definition of species, there can’t possibly be intermingling species: species are reproductive islands, isolated from each other by the fact that they can’t have fruitful offspring from cross-breeding. This is obviously not what is involved when people start talking about interbreeding between species: interbreeding between populations that can’t fruitfully interbreed is necessarily a dead end at best and in most cases simply a nonstarter. So in those cases, some other biological concept of species must be involved. (Since scientists tend to operationalize when they define their terms, biological concepts of species multiply like crazy.)

    When we are talking about species in the sense relevant to polygenism, though, we are talking about nature — animals, and as far as we have any evidence for, particularly hominids, with intellect and will, capable of moral choice — and while it may well be that certain biological characteristics are signs of having the same human nature, we obviously have no reason to think them infallible guides in this regard, and the best evidences are not biological at all, except in the sense that rational animals may be the cause of them. Therefore we can never simply move from one discourse to another. Whenever we hear about scientific polygenism, then, since scientific claims have no value beyond what they get from their evidence and inferences from that evidence, we need to ask, “What does this claim actually mean given the actual evidence on which it is based?” Failure to do this virtually guarantees equivocation. Likewise, going the other direction, we have to recognize that the basic features of human nature are very specific (Mike’s true man point), and it is only those that are seriously in view if we are talking about things like original sense. We really need translations more than anything.

    • September 6, 2011 at 2:07 pm

      I think that you are correct in the fear of equivocation. Also, I think it is unclear what sense of the term is being used in Humani Generis. It is unclear because it is not always the case that the Church uses the strict philosophical terminology. Rather, it can happen that encyclical terminology follows the language used by those to whom the encyclical is responding. A good example of this is the condemnation of “teleological moralities” in Veritatis Splendor. While this is the case, we ought not to underplay the relationship between logical and biological species. Some would argue that one of the problems in contemporary divisions is that they are inherently nominalist and thus inherently flawed. In other words, which type of species is the foundation for the other type of species?

      • Brandon said,

        September 6, 2011 at 2:20 pm

        Very much agreed on the encyclical language point.

        Some would argue that one of the problems in contemporary divisions is that they are inherently nominalist and thus inherently flawed.

        Well, I think the issue would be flawed for what purpose. Stipulating definitions of words and making use of imperfect descriptions can be perfectly legitimate in many circumstances; one should just not confuse them with complete definitions of things themselves. I am skeptical of suggestions that scientific descriptions are inherently nominalistic; and I am also increasingly skeptical of the common assumption that there is anything more than a very indirect connection between logical and at least many biological concepts of species — of the latter of which, again, we find an extraordinary number of different kinds.

      • September 6, 2011 at 5:13 pm

        Yes, Brandon, the nominalism card is often played too soon. I don’t know enough about the modern method of classification to be able to distinguish it from the method Aristotle used (what I called logical above). I do remember that Aristotle’s method was the Gold Standard of classification until the recent method was developed. My question would be about what is considered essential to a definition. I think that this is essential to the conversation at hand, however, because it would help us understand what the traditional position means by man contrasted with what the critics of the traditional position understand to be man.

  18. Mike Flynn said,

    September 6, 2011 at 3:00 pm

    “I look at the term species as one arbitrarily given, for the sake of convenience, to a set of individuals closely resembling each other…”
    — Charles Darwin, The Origin of Species

    “Whoever, like Darwin, denies that species are non-arbitrarily defined units of nature not only evades the issue but fails to find and solve some of the most interesting problems of biology.”
    — Ernst Mayr, Animal Species and Evolution

    at least many biological concepts of species — of the latter of which, again, we find an extraordinary number of different kinds.

    Right. The “interfertile” definition is flawed because not all kinds are sexually reproductive. One botanist – I forget who – opined that the usual definition of species was ‘animal-centric’ and did not sit well on plants or fungi; let alone on protists.

%d bloggers like this: