In "The Edge of Evolution," Michael Behe proposes an eponymous edge of evolution. In "Evolution Unscathed," Behe's colleagues Gregory Lang and Amber Rice give that edge an almost imperceptible nudge.
I've got thoughts on points 4) originality, 5) the text metaphor, and 6) irreducible complexity) as well as the larger theme of philosophical insufficiency, but I thought I'd briefly note 1) what I think the importance of this discussion is, 2) what I understand your view to be, and 3) what I'd like to persuade you of.
1) In brief, I think that one challenge the church in the present period faces is of synthesizing a world picture that satisfactorily explains both natural science (both the biological and non-biological) as the distributed tradition we experience today and the Bible as historically interpreted by the church. I think the clarity, rationality, and power of that synthesis would be directly relevant to the church's evangelical mission (both within the church to the next generation and outside to the world). I do think this is clearly secondary to the church's moral and charitable distinctiveness, but that it does still matter to many people and mission fields (I have many friends in the sciences for whom this synthesis is significant).
2) I take your overarching perspective to be that evolutionary naturalism can be carved out of the natural sciences (the rest of which can be essentially accepted) as a scientific paradigm that ought to be rejected. Further, it seems to me that you think we ought to reject it on scientific grounds, in essence that it is a clearly failed (and maybe even incoherent philosophically?) paradigm that only persists among scientists out of an unimaginative methodological naturalism.
3) I would like to persuade you that this view of the science is incorrect, that evolution by genetic change is a successful and productive theoretical paradigm, and that the same arguments that would lead Christians to accept the theories of physicists should lead us to accept the theories of biologists.
4) I confess I'm not sure I completely understand your philosophical issue, but my interpretation is that you believe that Lang and Rice are making a categorical error. That is to say, they are not realizing the transformative importance of the categorical distinction between original newness and mere pro forma novelty. I agree that there is an important categorical distinction between 'original' and 'new', otherwise 'paraphrase' would be an incoherent idea (along with related ideas like copy and derivative). But I also think that is essential when philosophizing about a discipline to determine whether those categories meaningfully apply to the discipline in question.
You agree that new genetic code can be added to a given genome and agree that mutation can result in a new genetic code, but you propose that something more is required: an 'original' element and that that 'original' element is what is necessary to change from an existing biological family to a new one. Why should we think that that is the case? In fact the really radical element of the evolutionary paradigm is that there isn't anything unique that separates some kind of eukaryotes from others (prokaryotes are different enough that I think it is debatable whether they represent a real difference in kind). That, for example, dogs could continue to be bred and changed to fill arbitrary ecological niches until they could resemble and thrive as animals that would seem to us more like cows, or fish, or even plants and micro-organisms. It seems to me that a claim of necessary originality must identify some point (i.e. evolution's edge from Behe's book) where the process of continuous change of genetic code must stop, and why (i.e. some blocker or barrier) it is impossible for it to go beyond that point. You seem to me to be agreeing that Lang and Rice successfully point out that novelty as such is not that blocker, and I'm not sure how to give a biological meaning to the originality problem (you've mentioned that it has to do with 'family', but as far as I can tell the family vs order distinction is a historical eyeballing of difference and has no physical motivation, so I don't understand how it could be a barrier).
It seems worth responding as well to two related ideas from your treatment of Aristotle. To restate the radical idea mentioned above (but more explicitly), the core conception is to deny that organisms (like say a tiger) have their own nature that gives rise to formal causation. Instead nature (and thus formal causation) is attributed to a) more basic building blocks, from cells to the particles of the Standard Model of physics that mechanically specify an organism and b) the fitness-shaping characteristics of particular ecosystem-specific niches which provide the direction for refining the formal structure of an organism. Further if the nature of those ecosystem-specific niches or basic building blocks are themselves intelligently ordered (i.e. God created an orderly, intelligible universe), we are not claiming that chance is logically prior to intelligence. This second point goes to the essential paradigmatic critique of all natural science, which is that the intelligibility of the universe is unexplained.
5) I think the analogy from Shakespeare is not persuasive and if used to represent the biological reality, cuts against your argument. I take the argument to be that given 'Hamlet' (or some other play), you cannot produce some new in content (i.e. a novel story as we would recognize it) story merely by adding, deleting, inserting, rearranging, modifying, or changing letters, words, phrases, sentences, scenes, and acts. As Hamlet is an English text in some order and Paradise Lost is also an English text in some order, and that therefore there obviously exists some series of steps that would follow those rules and transform one into the other (i.e. there is no blocker of mechanism to going from Hamlet to Paradise Lost), the real kicker of the analogy must be the requirement that the text 'keep surviving' after each generation or step. Given that the biological criterion is fitness for replication, the natural survival criterion would be that after each step of change from Hamlet the text would retain enough story content to be retold again. An empirically testable claim seems to appear here. Taking a large population of copies (maybe 10,000?) of Hamlet, have a computer copy a new larger generation (say 100,000) in a lossy way (i.e. including our changes as described above), have human readers (or a substitute like GPT-4) evaluate the 10,000 fittest (in this context meaning most coherent English, or most recognizable story, or pure most preferred) and have this process repeat. I would predict the evolution of recognizably distinct dramatic plots (Hamlet leads a rebellion, or is killed and Horatio gets revenge). I would further predict that it would be possible to get the text to converge on Paradise Lost if an additional fitness signal was added for similarity to Milton's epic. It seems to me that your prediction must be that this would be impossible. Why?
6) The blocker that has been proposed (for the cause of Evolution's Edge) is irreducible complexity, and you seem to allow that Lang and Rice have shown that this is not actually a blocker in a universal and conceptual sense. I interpret you as still arguing that it may be so in a practical sense in many (perhaps most?) cases, and so the fact that irreducible complexity is not in fact a blocker in principle doesn't really matter. I think this is a categorical mistake about the kinds of objections that are reasonable to a scientific paradigm, and therefore the kind of objections that are reasonable for non-scientist observers to make.
Following Kuhn, I take sciences (in this case evolutionary biology as a subfield of physical science generally) to be traditions of problem-solvers organized around a common theory (in this case DNA-modulated evolution as a sub-theory of genetics). For a given tradition, the theory provides practitioners with a paradigm for understanding what the relevant problems are, what meaningful evidence would be, what counts as evidence, and how to make arguments about that evidence. A successful theory coherently and elegantly explains an accepted body of observations and provides further direction for exploration, application, and expansion. On those grounds, evolutionary biology is a field with a very successful theory.
In criticizing a theory, there are two paths one might use. First, you might make a theoretical objection to some element of the theory, a pastime for which philosophers can be well-suited (I myself enjoy poking at the various theoretical problems with psychology for example, or the well known incompatibility between general relativity and quantum mechanics). Second, you might make an observational objection about how some specific observation doesn't accord with the theory. This second category of objection requires you to be as conversant with the theory as practitioners are, which makes non-participating observers ill-suited for championing such objections.
So if Behe's irreducible complexity fails as a theoretical critique of the evolutionary paradigm (which you seem to me to have recognized), then it can only persist as an observational critique of specific examples, and cannot function as a categorical blocker for evolutionary change. Further, as non-specialists, adjudicating observational critiques of the evolutionary paradigm is beyond our training and is something that needs to be done by specialists (who by Lang and Rice's example seem to be, perhaps unfairly, unpersuaded).
What critique remains? For scientific critiques, perhaps a new theoretical problem that would block change according to DNA can be identified (not to mention that there are theoretical weaknesses to current explanations about the origin of the DNA replication toolset, along with complex Eukaryotic life, and perhaps multi-cellularity). We also have a paradigmatic critique (which I agree with by the way) that the present theoretical paradigm doesn't strongly include the teleological elements of the biological system (i.e. order and structure is only weakly explained in terms of niches). I in fact do predict that a richer theoretical paradigm which encompasses both genetic evolution and homomorphic-ecosystemic co-evolution (which would be a sort of higher-dimensional platonic account of environment structure as such) will emerge to better describe both cellular and macro environments, but I think it is extremely likely that descent by heredity will be preserved in such a transformation (in the same way that force survived the Newtonian -> Relativistic transformation).
Absent a live theoretical objection though, evolutionary biology appears to be a productive and powerful paradigm where scientists can work fruitfully to answer questions and make observations (and whose observations can be used to do engineering to accomplish human goals). It should therefore be accepted on the same terms (or rejected on the same terms) as the other natural sciences.
Paul, thanks for your thoughtful comments - you inspired the post, of course, so great to see your reaction to it!
1) I absolutely agree on the role of this issue in Christian witness. The Christian approach to science and faith is not everyone's issue and is less important than its witness moral. BUT, it is emblematic of a general approach to Christ and culture, whether more insular and confrontational or synthetic and cordial, let's say.
2) Yes - in the next post, I'm going to elucidate the distinction between, as Stephen Meyer puts it, historical and experimental science. Experimental science examines the on-going workings of nature, seeking natural laws and the like. A kind of methodological naturalism is appropriate there. Historical science, which is closely connected with natural history, is concerned with things that happened in the past, but have ongoing effects. There is no constraint a priori that nothing supernatural ever happened or that a supernatural agent ever had a role in creating the universe or parts of it. Methodological naturalism doesn't hold there. So the whole body of experimental natural science holds together - Christians don't need to "carve out" anything.
3) Sounds great - persuade away! One obstacle is the great difference between the theories of physics and those of biologists - namely, that a key "theory" of biology is a theorem about natural history. As a piece of experimental science, Behe, for example, accepts Darwin's theory and shows the limits of what evolution by Neo-Darwinian mechanism can do.
4) Let me focus one of your sentences: "You propose that something more is required: An 'original' element and that that 'original' element is what is necessary to change from an existing biological family to a new one." Yes, and I do think this leads to real barriers between biological kinds, which might be, as Behe indicates, at the taxon "family." But my key argument is that random mutation and natural selection can only get started GIVEN some "original genetic information," namely, the information to code for a fully-functioning living organism that is able to self-replicate another organism very much like it. Given that that must be in place, variation can only happen "on top of that." As a result, variation can only affect a kind of "top layer" of phenotypic features, or so I would argue. But more needs to be said.
5) William Dembski is really important for this part of the discussion. The probability boundary for one specifiedly complex body of information to be transformed into another by random change and "survival" (or the textual equivalent) is enormous. I think people view the fact that it is not physically impossible in some bare sense for an event of probability 1/10^10^1000 to occur as, "So it really is possible!" In fact, there are probability boundaries in common use in different areas of mathematics in science according to which, such things are reasonably said to be impossible. Could God do it? If we go that route, then Intelligent Design has been accepted - and we can talk about that if you want to propose that evolution occurred but it HAD to be directed by God.
I want to say more on irreducible complexity, and I don't think I meant to concede that is not an obstacle. But I want to get some initial thoughts to you, so there's a start!
#6. The blocker at the edge of evolution is best explained in Behe's book, "The Edge of Evolution." This book is not about irreducible complexity at all. It is about observed difficulties in mutations that would require more than a single change (a point mutation), and how the very low probabilities of simultaneous mutations lead to insurmountable difficulties when we deal with the generation times and population sizes of land animals, for example, as opposed to single-celled organisms. I won't try to present the whole book here.
I think we are talking past each other. I think something can be a blocker to a process in two different senses. First something might be a practical blocker because of the specific details of some process and our constraints. Second something might be a conceptual blocker, such that no practical analysis is necessary to show that something can't be done. Compare for example me being blocked from walking from Chicago to Mexico City to me being blocked from walking from Chicago to the Moon.
It seems to me that Behe and others are offering a blocker of the first kind. They are arguing that it is not in principle impossible for Evolution to give rise to the speciation that we see, but that they think it is just too unlikely on one model of the process. They are not arguing that there is some categorical/conceptual barrier to evolution.
This creates two problems for Christians who want to argue against evolution. 1) There are a lot of possible models for how evolution could function, and showing that one specific model (or even a class of models) is very improbable isn't sufficient for rejecting the enormous weight of evidence for evolution. 2) This is a matter of biological scientific judgement, not a point to be evaluated in the armchair by non-specialist philosophers, especially since the Behe and others agree that in principle if given arbitrary time evolution could produce the speciation we see (which is the whole ballgame for attempting to stress something categorically special about humans or other creatures).
Therefore I continue to think that it is irresponsible and deeply foolish for Christian leaders to be stressing opposition to evolution.
I think we are talking past each other because you are dealing in abstractions rather than addressing the actual examples given by Behe and others. "Given enough time" is a prime example. We know how little time is available for certain things, e.g. the Cambrian explosion. So it makes no sense to say that there is no conceptual problem with that much evolution occurring, given a trillion years time to do so, when we know that we have orders of magnitude less time than that.
I think my position from my point #6 is that it is unreasonable for non-scientists to try and adjudicate a technical scientific argument, which is what the argument between Behe and mainstream biologists is. In the absence of categorical and philosophical objection, I don't think we are justified in rejecting evolution. That is why I wrote what I did against Joel's 'creative work' argument.'
*I think on Behe's specific biological claims about Evolution the linked review gives a clear response (Evolution Unscathed).
I think it is reasonable for those outside of evolutionary biology to read a conversation and decide who is most convincing. For example, I can read a review (Evolution Unscathed) and read the four online responses to that review, and decide who is making general statements without providing examples and evidence to back up those statements, and who (by contrast) is providing detailed examples to support an argument.
As a specific example, read just part 1 of Behe's response to the Evolution Unscathed review. If there is a rebuttal posted somewhere, I would be glad to read it. That is how the evaluation of a complex subject should proceed. At some point, the back-and-forth comes to a halt, or you notice that people are just repeating themselves, and you have all the input you are going to get for the moment, so it is time for you to at least tentatively make up your mind.
Do you have any rebuttal to what Behe says? Having read the review and his replies, I find him MUCH more convincing. There are simple logical inconsistencies in the review, and the review's claims of logical problems in Behe's books are refuted. Do we have to have a Ph.D. in either biology or philosophy to follow logical claims?
It is critical for each of us to be able to follow the arguments that others make in order to evaluate issues of importance. Otherwise, we address each issue by saying "I have to defer to the experts." Public health "experts" said that schoolchildren should be kept 6 feet apart in the fall of 2020 when returning to school during COVID. Researchers studied two adjacent school districts in Massachusetts, one of which had the 6-foot rule and one of which had a 3-foot rule, and found no difference in spread of cases. But, I am not a public health expert, nor an epidemiologist, so I cannot evaluate this technical argument for myself, right?
The problem is that worldviews can shape the "consensus" of a particular community of researchers. Deferring to that consensus then implies not merely recognizing someone's expertise, but deferring to their worldviews and related prejudices.
I encourage readers to go to the website linked early in this post to read four different rebuttal articles to the Lang and Rice review (three of them being a three-part rebuttal from Michael Behe). Some of the Lang and Rice points that seem to be accepted in this post have actually been refuted, e.g. the frequency of loss of function mutations.
In two comments: Part 1
I've got thoughts on points 4) originality, 5) the text metaphor, and 6) irreducible complexity) as well as the larger theme of philosophical insufficiency, but I thought I'd briefly note 1) what I think the importance of this discussion is, 2) what I understand your view to be, and 3) what I'd like to persuade you of.
1) In brief, I think that one challenge the church in the present period faces is of synthesizing a world picture that satisfactorily explains both natural science (both the biological and non-biological) as the distributed tradition we experience today and the Bible as historically interpreted by the church. I think the clarity, rationality, and power of that synthesis would be directly relevant to the church's evangelical mission (both within the church to the next generation and outside to the world). I do think this is clearly secondary to the church's moral and charitable distinctiveness, but that it does still matter to many people and mission fields (I have many friends in the sciences for whom this synthesis is significant).
2) I take your overarching perspective to be that evolutionary naturalism can be carved out of the natural sciences (the rest of which can be essentially accepted) as a scientific paradigm that ought to be rejected. Further, it seems to me that you think we ought to reject it on scientific grounds, in essence that it is a clearly failed (and maybe even incoherent philosophically?) paradigm that only persists among scientists out of an unimaginative methodological naturalism.
3) I would like to persuade you that this view of the science is incorrect, that evolution by genetic change is a successful and productive theoretical paradigm, and that the same arguments that would lead Christians to accept the theories of physicists should lead us to accept the theories of biologists.
4) I confess I'm not sure I completely understand your philosophical issue, but my interpretation is that you believe that Lang and Rice are making a categorical error. That is to say, they are not realizing the transformative importance of the categorical distinction between original newness and mere pro forma novelty. I agree that there is an important categorical distinction between 'original' and 'new', otherwise 'paraphrase' would be an incoherent idea (along with related ideas like copy and derivative). But I also think that is essential when philosophizing about a discipline to determine whether those categories meaningfully apply to the discipline in question.
You agree that new genetic code can be added to a given genome and agree that mutation can result in a new genetic code, but you propose that something more is required: an 'original' element and that that 'original' element is what is necessary to change from an existing biological family to a new one. Why should we think that that is the case? In fact the really radical element of the evolutionary paradigm is that there isn't anything unique that separates some kind of eukaryotes from others (prokaryotes are different enough that I think it is debatable whether they represent a real difference in kind). That, for example, dogs could continue to be bred and changed to fill arbitrary ecological niches until they could resemble and thrive as animals that would seem to us more like cows, or fish, or even plants and micro-organisms. It seems to me that a claim of necessary originality must identify some point (i.e. evolution's edge from Behe's book) where the process of continuous change of genetic code must stop, and why (i.e. some blocker or barrier) it is impossible for it to go beyond that point. You seem to me to be agreeing that Lang and Rice successfully point out that novelty as such is not that blocker, and I'm not sure how to give a biological meaning to the originality problem (you've mentioned that it has to do with 'family', but as far as I can tell the family vs order distinction is a historical eyeballing of difference and has no physical motivation, so I don't understand how it could be a barrier).
It seems worth responding as well to two related ideas from your treatment of Aristotle. To restate the radical idea mentioned above (but more explicitly), the core conception is to deny that organisms (like say a tiger) have their own nature that gives rise to formal causation. Instead nature (and thus formal causation) is attributed to a) more basic building blocks, from cells to the particles of the Standard Model of physics that mechanically specify an organism and b) the fitness-shaping characteristics of particular ecosystem-specific niches which provide the direction for refining the formal structure of an organism. Further if the nature of those ecosystem-specific niches or basic building blocks are themselves intelligently ordered (i.e. God created an orderly, intelligible universe), we are not claiming that chance is logically prior to intelligence. This second point goes to the essential paradigmatic critique of all natural science, which is that the intelligibility of the universe is unexplained.
Part 2:
5) I think the analogy from Shakespeare is not persuasive and if used to represent the biological reality, cuts against your argument. I take the argument to be that given 'Hamlet' (or some other play), you cannot produce some new in content (i.e. a novel story as we would recognize it) story merely by adding, deleting, inserting, rearranging, modifying, or changing letters, words, phrases, sentences, scenes, and acts. As Hamlet is an English text in some order and Paradise Lost is also an English text in some order, and that therefore there obviously exists some series of steps that would follow those rules and transform one into the other (i.e. there is no blocker of mechanism to going from Hamlet to Paradise Lost), the real kicker of the analogy must be the requirement that the text 'keep surviving' after each generation or step. Given that the biological criterion is fitness for replication, the natural survival criterion would be that after each step of change from Hamlet the text would retain enough story content to be retold again. An empirically testable claim seems to appear here. Taking a large population of copies (maybe 10,000?) of Hamlet, have a computer copy a new larger generation (say 100,000) in a lossy way (i.e. including our changes as described above), have human readers (or a substitute like GPT-4) evaluate the 10,000 fittest (in this context meaning most coherent English, or most recognizable story, or pure most preferred) and have this process repeat. I would predict the evolution of recognizably distinct dramatic plots (Hamlet leads a rebellion, or is killed and Horatio gets revenge). I would further predict that it would be possible to get the text to converge on Paradise Lost if an additional fitness signal was added for similarity to Milton's epic. It seems to me that your prediction must be that this would be impossible. Why?
6) The blocker that has been proposed (for the cause of Evolution's Edge) is irreducible complexity, and you seem to allow that Lang and Rice have shown that this is not actually a blocker in a universal and conceptual sense. I interpret you as still arguing that it may be so in a practical sense in many (perhaps most?) cases, and so the fact that irreducible complexity is not in fact a blocker in principle doesn't really matter. I think this is a categorical mistake about the kinds of objections that are reasonable to a scientific paradigm, and therefore the kind of objections that are reasonable for non-scientist observers to make.
Following Kuhn, I take sciences (in this case evolutionary biology as a subfield of physical science generally) to be traditions of problem-solvers organized around a common theory (in this case DNA-modulated evolution as a sub-theory of genetics). For a given tradition, the theory provides practitioners with a paradigm for understanding what the relevant problems are, what meaningful evidence would be, what counts as evidence, and how to make arguments about that evidence. A successful theory coherently and elegantly explains an accepted body of observations and provides further direction for exploration, application, and expansion. On those grounds, evolutionary biology is a field with a very successful theory.
In criticizing a theory, there are two paths one might use. First, you might make a theoretical objection to some element of the theory, a pastime for which philosophers can be well-suited (I myself enjoy poking at the various theoretical problems with psychology for example, or the well known incompatibility between general relativity and quantum mechanics). Second, you might make an observational objection about how some specific observation doesn't accord with the theory. This second category of objection requires you to be as conversant with the theory as practitioners are, which makes non-participating observers ill-suited for championing such objections.
So if Behe's irreducible complexity fails as a theoretical critique of the evolutionary paradigm (which you seem to me to have recognized), then it can only persist as an observational critique of specific examples, and cannot function as a categorical blocker for evolutionary change. Further, as non-specialists, adjudicating observational critiques of the evolutionary paradigm is beyond our training and is something that needs to be done by specialists (who by Lang and Rice's example seem to be, perhaps unfairly, unpersuaded).
What critique remains? For scientific critiques, perhaps a new theoretical problem that would block change according to DNA can be identified (not to mention that there are theoretical weaknesses to current explanations about the origin of the DNA replication toolset, along with complex Eukaryotic life, and perhaps multi-cellularity). We also have a paradigmatic critique (which I agree with by the way) that the present theoretical paradigm doesn't strongly include the teleological elements of the biological system (i.e. order and structure is only weakly explained in terms of niches). I in fact do predict that a richer theoretical paradigm which encompasses both genetic evolution and homomorphic-ecosystemic co-evolution (which would be a sort of higher-dimensional platonic account of environment structure as such) will emerge to better describe both cellular and macro environments, but I think it is extremely likely that descent by heredity will be preserved in such a transformation (in the same way that force survived the Newtonian -> Relativistic transformation).
Absent a live theoretical objection though, evolutionary biology appears to be a productive and powerful paradigm where scientists can work fruitfully to answer questions and make observations (and whose observations can be used to do engineering to accomplish human goals). It should therefore be accepted on the same terms (or rejected on the same terms) as the other natural sciences.
Paul, thanks for your thoughtful comments - you inspired the post, of course, so great to see your reaction to it!
1) I absolutely agree on the role of this issue in Christian witness. The Christian approach to science and faith is not everyone's issue and is less important than its witness moral. BUT, it is emblematic of a general approach to Christ and culture, whether more insular and confrontational or synthetic and cordial, let's say.
2) Yes - in the next post, I'm going to elucidate the distinction between, as Stephen Meyer puts it, historical and experimental science. Experimental science examines the on-going workings of nature, seeking natural laws and the like. A kind of methodological naturalism is appropriate there. Historical science, which is closely connected with natural history, is concerned with things that happened in the past, but have ongoing effects. There is no constraint a priori that nothing supernatural ever happened or that a supernatural agent ever had a role in creating the universe or parts of it. Methodological naturalism doesn't hold there. So the whole body of experimental natural science holds together - Christians don't need to "carve out" anything.
3) Sounds great - persuade away! One obstacle is the great difference between the theories of physics and those of biologists - namely, that a key "theory" of biology is a theorem about natural history. As a piece of experimental science, Behe, for example, accepts Darwin's theory and shows the limits of what evolution by Neo-Darwinian mechanism can do.
4) Let me focus one of your sentences: "You propose that something more is required: An 'original' element and that that 'original' element is what is necessary to change from an existing biological family to a new one." Yes, and I do think this leads to real barriers between biological kinds, which might be, as Behe indicates, at the taxon "family." But my key argument is that random mutation and natural selection can only get started GIVEN some "original genetic information," namely, the information to code for a fully-functioning living organism that is able to self-replicate another organism very much like it. Given that that must be in place, variation can only happen "on top of that." As a result, variation can only affect a kind of "top layer" of phenotypic features, or so I would argue. But more needs to be said.
5) William Dembski is really important for this part of the discussion. The probability boundary for one specifiedly complex body of information to be transformed into another by random change and "survival" (or the textual equivalent) is enormous. I think people view the fact that it is not physically impossible in some bare sense for an event of probability 1/10^10^1000 to occur as, "So it really is possible!" In fact, there are probability boundaries in common use in different areas of mathematics in science according to which, such things are reasonably said to be impossible. Could God do it? If we go that route, then Intelligent Design has been accepted - and we can talk about that if you want to propose that evolution occurred but it HAD to be directed by God.
I want to say more on irreducible complexity, and I don't think I meant to concede that is not an obstacle. But I want to get some initial thoughts to you, so there's a start!
#6. The blocker at the edge of evolution is best explained in Behe's book, "The Edge of Evolution." This book is not about irreducible complexity at all. It is about observed difficulties in mutations that would require more than a single change (a point mutation), and how the very low probabilities of simultaneous mutations lead to insurmountable difficulties when we deal with the generation times and population sizes of land animals, for example, as opposed to single-celled organisms. I won't try to present the whole book here.
I think we are talking past each other. I think something can be a blocker to a process in two different senses. First something might be a practical blocker because of the specific details of some process and our constraints. Second something might be a conceptual blocker, such that no practical analysis is necessary to show that something can't be done. Compare for example me being blocked from walking from Chicago to Mexico City to me being blocked from walking from Chicago to the Moon.
It seems to me that Behe and others are offering a blocker of the first kind. They are arguing that it is not in principle impossible for Evolution to give rise to the speciation that we see, but that they think it is just too unlikely on one model of the process. They are not arguing that there is some categorical/conceptual barrier to evolution.
This creates two problems for Christians who want to argue against evolution. 1) There are a lot of possible models for how evolution could function, and showing that one specific model (or even a class of models) is very improbable isn't sufficient for rejecting the enormous weight of evidence for evolution. 2) This is a matter of biological scientific judgement, not a point to be evaluated in the armchair by non-specialist philosophers, especially since the Behe and others agree that in principle if given arbitrary time evolution could produce the speciation we see (which is the whole ballgame for attempting to stress something categorically special about humans or other creatures).
Therefore I continue to think that it is irresponsible and deeply foolish for Christian leaders to be stressing opposition to evolution.
I think we are talking past each other because you are dealing in abstractions rather than addressing the actual examples given by Behe and others. "Given enough time" is a prime example. We know how little time is available for certain things, e.g. the Cambrian explosion. So it makes no sense to say that there is no conceptual problem with that much evolution occurring, given a trillion years time to do so, when we know that we have orders of magnitude less time than that.
I think my position from my point #6 is that it is unreasonable for non-scientists to try and adjudicate a technical scientific argument, which is what the argument between Behe and mainstream biologists is. In the absence of categorical and philosophical objection, I don't think we are justified in rejecting evolution. That is why I wrote what I did against Joel's 'creative work' argument.'
*I think on Behe's specific biological claims about Evolution the linked review gives a clear response (Evolution Unscathed).
I think it is reasonable for those outside of evolutionary biology to read a conversation and decide who is most convincing. For example, I can read a review (Evolution Unscathed) and read the four online responses to that review, and decide who is making general statements without providing examples and evidence to back up those statements, and who (by contrast) is providing detailed examples to support an argument.
As a specific example, read just part 1 of Behe's response to the Evolution Unscathed review. If there is a rebuttal posted somewhere, I would be glad to read it. That is how the evaluation of a complex subject should proceed. At some point, the back-and-forth comes to a halt, or you notice that people are just repeating themselves, and you have all the input you are going to get for the moment, so it is time for you to at least tentatively make up your mind.
Do you have any rebuttal to what Behe says? Having read the review and his replies, I find him MUCH more convincing. There are simple logical inconsistencies in the review, and the review's claims of logical problems in Behe's books are refuted. Do we have to have a Ph.D. in either biology or philosophy to follow logical claims?
It is critical for each of us to be able to follow the arguments that others make in order to evaluate issues of importance. Otherwise, we address each issue by saying "I have to defer to the experts." Public health "experts" said that schoolchildren should be kept 6 feet apart in the fall of 2020 when returning to school during COVID. Researchers studied two adjacent school districts in Massachusetts, one of which had the 6-foot rule and one of which had a 3-foot rule, and found no difference in spread of cases. But, I am not a public health expert, nor an epidemiologist, so I cannot evaluate this technical argument for myself, right?
The problem is that worldviews can shape the "consensus" of a particular community of researchers. Deferring to that consensus then implies not merely recognizing someone's expertise, but deferring to their worldviews and related prejudices.
I encourage readers to go to the website linked early in this post to read four different rebuttal articles to the Lang and Rice review (three of them being a three-part rebuttal from Michael Behe). Some of the Lang and Rice points that seem to be accepted in this post have actually been refuted, e.g. the frequency of loss of function mutations.