One of the central tenants of Darwinian selection is that natural selection acts on preexisting genetic variation. So the neo-Darwinian theory of evolution is indeed falsifiable to some extent. All you need to do is find an instance where genetic changes occurred as a result of selection rather than prior to it. Specifically, these changes must occur highly disproportionately at the sites of selection, rather than just having an overall increased mutation rate. An example of this type of challenge was in 1988 when John Cairns proposed a possible example of directed mutation in the lactose operon in E. coli. This stimulated a fair amount of research into the phenomenon, with the final consensus being that the phenomenon was consistent with neo-Darwinian theory, and the Lamarckian appearance of the phenomenon was an artifact. The literature on the subject is quite rich, and worth looking into for anyone who wants to see what a real scientific challenge to neo-Darwinian theory looks like, and how it is investigated by empirical scientists.

A very short answer: if paleontologists find distinctive human bones that could be dated to over 15 million years. That would make us rethink much of what is known. Or we could find an organism with a completely different genetic code. This is just an example of the many things that theoretically could happen. Also molecular phylogenetics has the theoretical capability to disprove existing New Darwinian ideas. Only problem is that so far all the evidence supports it. 

Alexander Panchin thanks for answer. But I asked by the conditions that can refute the neodarwinian theory of evolution, no the evolution in general. I can reformulate the question as How do we can reject and change the paradigm of the neodarwinism (or the Modern synthesis MS) by a new or an alternative paradigm? given that this theory is about the mechanism of evolution

Why the existence of an organism with a completely different genetic code can refute the neodarwinian theory? If there are other life forms, the posibility that they have another genetic code is high, and it doesn't deny that their form of evolutuion can be described by the population genetics

What do you refer with this "molecular phylogenetics has the theoretical capability to disprove existing New Darwinian ideas. Only problem is that so far all the evidence supports it. "

Neo darwinism cannot be discussed because is a very relaxed theory that accept almost everything, even if data are contradictory. If not, endosymbiosis should be an argument to reject the competitivity hypothesis but once it was proposed it was included in the "more modern neo darwinism". Or miRNA regulation in different part of the body as the miRNA is produced in a particular cell and is being transmited in an epigenetic way.

Epigenetic and HGT (Horizontal Gene Trasnference) would be other to refutations of the NEO Neodarwinism, but they are compiled in NEO NEO NEOdarwinism. Paternal inheritance of somatic mutations in immune system cells (proven in 1984) is another refutation for NEO NEO NEOdarwinism, but, at first, it was ignored and, nowadays, it is inclueded in NEO NEO NEO NEOdarwinism. 

I hope I have been enough clear. I think Neodarwinism was rejected since russians in the beggining of XX century proposed collaboration instead of competitivity to generate diversity and new species (Lynn Margulis, Steele, and other authors, recovered and renewed this information in the second half of XX century). However, the social paradigm of Neodarwinism is still so strong that will not accept any information contrary to it. It will ignore it or, if the contradictory information is very strong, it will change little in order not to change.

Nice answer I wanted come to it.

Is there any antecedent of any scientific theory, in any field, of a theory so obstinate? is the expansion attitude going to go on for ever? is there any crucial experiment capable to refute this theory? What did have to say the epistemologists and science historians about a theory so shielded?

Another interpretation possible about this rare scientific behavior, could be that really no one biologist or philosopher follower (or not) of the MS has identified the central theory core or the philosophical principles susceptible to be contradict them, and for that reason every fact is compatible with the MS (or if somebody has identified, the orthodoxy hasn't left him/her get diffuse him/her ideas)

What do you think Ignacio? 

I think that, following Khun and his "structure of the scientific revolutions" (paradigm_expansion->anomaly->crisis->revolution->new_paradigm), it could take way more time to accomplish in biological sciences than in other scientific disciplines (as e.g. physics). That is because biology has a strongly different nature than physics where experimenting could be more definitive and conclusive given the deterministic nature of it processes. In contrast, biology is now being considered more on the hyper-complex and hyper-extensive side of science, so a lot of research and time could be necessary to show the "anomalies" in the paradigm.

However, it is possible that Neodarwinism is not as shielded as we can think, probably there are already some cracks in the armor. For example the phenomenon of genomic imprinting, or other experimental results, (already succesfully replicated and recognized) are completely Lamarckists and incompatible with Darwinism of any flavor. Also,  the mathematical basis of Neodarwinism had a lot of frequentist statistics, which could arguably settled to be replaced (in a middle-long term) by its arch-enemy Bayes. However, it could be quite difficult forecasting if the shift of paradigm will get too much resistance or take too long. According with Khun, the crisis that comes after the anomalies of the paqradigm are recognized (we could be in that stage), could lead to a new paradigm in maximum one generation. Or not.

However, (I´d like to think in that way) no scientific theory has probed to be without anomalies (theoretical or empirical contradictions). So, probably Neodarwinism is destined to be old but not immortal.    

I believe that I may have misunderstood your question at first. You are asking if something may refute Neodarwinism which is the modern synthesis of Darwinian evolution through natural selection with Mendelian genetics. How about a simpler question: can something refute the existence of natural selection or Mendelian genetics?

Both ideas of natural selection and Mendelian genetics are based on empirical research, experiments that could have confirmed or refuted these ideas that are the cornerstones of Neodarwinism. It turned out that research confirms that there is in fact Mendelian inheritance, there are random mutations that occur due to non-directed chemical processes and there is natural selection and natural selection can lead to speciation. However, if errors are found in all this research, then, theoretically Neodarwinism could be refuted. But it is very unlikely that we are so wrong about these things. That is why it seems that Neoderwanism is irrefutable. Not because research studies can’t disprove it in principal, but because so far they have only confirmed the core principals and you would need something very solid to prove that all that research is wrong. 

In this sense Neodarwinism is like gravity. Can you refute gravity? Well... The existence of gravity is based on physical experiments we can perform and have performed in the past. If there was no gravity, you could easily refute its existence by a simple experiment. Practically, however, you won't be able to do that, because most likely gravity does exist, it is not a figment of our imagination and any experiment you perform will only confirm its existence. What can happen is you can improve the theory of gravity by finding new details, something else that also exists and contributes to the phenomena. Such as confirm or refute the existence of the Higgs boson e.t.c.

In the case of Neodarwinism we could find instances, say, of Lamarckian evolution. For example, cryptic genes allow bacteria to transfer acquired adaptations to the next generation (see this article: http://mbe.oxfordjournals.org/content/1/1/109.short). This mechanism appears to play an important role in bacterial evolution. This mechanism is not Darwinian evolution, but it itself probably did evolve via Darwinian evolution. And it could be a better explanation to certain observations that we previously explained as a resilt of Darwininan evolution. But does this, or epigenetics or horizontal gene transfer refute Neodarwinism as a whole? Of course not.

But that does not mean that Neodarwinism isn’t falsifiable in the strict sense of the scientific criteria formulated by Popper. It just means that critical experiments have already been performed multiple times and yielded so much confirmation that it is _unlikely_ to be refuted by any further investigation. Simple as that.

The neodarwinism isn't the simple sum of mendelian genetics and natural selection, this theory has its own concepts and tools. if ND was like that , a lot of time ago it would have been refuted , by the discovery that the most common patterns of inheritance are the non-mendenlian

A conceptual refutation of the natural selection doesn't means that someone that want refute it has to demonstrate how denies that it's exist, I would say that a conceptual or empirical refutation is about the interpretation of the natural selection, and it's not about it existence ('cause you said this is a certainty). I mean the reductionist interpretation of the natural selection where the gene is the unit or focus of this process (as the population genetics define this "force").

I think that the neodarwinism just exists like a cultural or traditional perspective, that the theoretical reality of the evolutioanary biology is the pluralism, a set of non completely compatible theories and this isn't much different to the M. Pigliucci's interpretation of the extended synthesis. But also the Neodarwinian has not clear philosophical bases that left him sees the theoretical pluralism.

Edson it's interesting the note about the frequentist statistics's arch-enemy Bayes, but do you can imagene how can this change will be possible? 

This is a good question, neodarwansim explain role of selection and mutation pressure on natural populations with all different environmental factors, Basically, three important processes mutation, genetic recombination and chromosomal changes play important role in  generation of variations and two more factors natural selection and reproductive isolation provide way to natural population to move ahead, now genetic drift, migration and hybridization are programming factors which act as accessory to support arrival of new genes. Further random mixing of genes or panmixis is responsible for generation of variations in natural population through selection. There si a pull and push mechanism which work at genome level of each and every organisms those who are following the path of  Mendelian interactions. Though all things are seemingly reported as natural happeinings, but selection prefers population with efficient forwarding gene interactions or only positive mutations are preferable allowed to survive in form of organically important species or races. But there are hierarchical evolution patterns which demonstarte both horizontal and vertical selection orders and gene transfers in bith Eukaryotes and prokaryotes.  

Dear Aimer,

Along centuries many hypothesis have been as persistent as Neodarwinism but the matter is not the persistence but the way it is used to reject or to absorb any data inside itself. Moreover, Science, in contrast to other ways of knowledge, should be constantly being challenged and in continuous change. 

Other examples of hard against data theories were the "humours theory" in medicine or the geocentric solar system in astronomy. But, both of them, were out of the information age and out of the Science age.

In Phylosophy degree, I have had many teachers sceptics about the power of Neodarwinism to explain anything and so I had when I studied Biology (but, in Biology, teachers were more conservative). Logic teachers talk about tautology, some historicians say that is a Theory to be contextualized in colonial England and its power to explain is limited to its context. I have had no Epistemiology yet so I cannot tell you directly what epistemiologists say about.

There is no crucial experiment able to to reject this Theory because its validation is not scientific but phylosophical as it can accept almost anything. In this context, it seems more a religion than a Theory. 

But also I have had phylosophers and biologist teachers who support strongly the value of this Theory.

As one colleague said befoer, Kuhn paradigms Theory should explain how it will fall somewhen but it cannot predict how and when. We are limited, and blinded in some cases, because we think that the breakage of the shield envolving the central core of the paradigm is enough to nude it so we cannot see its strenght. As you, more than probably, are Spanish speaker, you can read many articles in "www.somosbacteriasyvirus.com" written or compiled by a retired teacher of Antropology and Evolution in University Autonoma of Madrid.

"

"[La seleccion natural], su diosa principal, es veleidosa como los dioses del Olimpo. Dice el biólogo Fernando Vallejo “…caprichosa como las estaciones del año, cambia de parecer según el tiempo y el espacio. Aquí determina una cosa, allá otra; hoy quiere esto, mañana siempre no. Fantasmal, nunca da la cara, siempre actúa "per interposita" persona: unas veces es el clima, otras la salinidad del agua, otras los parásitos, la abundancia de depredadores, la escasez de presas, las plagas, los pájaros… y ha pasado a reemplazar a la Divina Providencia en las ciencias naturales."

Guillermo Agudelo "

Ideas diffuse very well in the information age but not in the big media. It is very common to find articles in which Natural Selection is named even if it is completely unnecessary to explain anything. 

What can I say if, even in the streets, you only can elect to be creationist or darwinist?

In spite of this, I partially accept "neodarwinism" to explain certain adaptation but, according with data, not to explain evolution.

There are many things to talk about this but it could be unapproachable.

Good luck!

One of the central tenants of Darwinian selection is that natural selection acts on preexisting genetic variation. So the neo-Darwinian theory of evolution is indeed falsifiable to some extent. All you need to do is find an instance where genetic changes occurred as a result of selection rather than prior to it. Specifically, these changes must occur highly disproportionately at the sites of selection, rather than just having an overall increased mutation rate. An example of this type of challenge was in 1988 when John Cairns proposed a possible example of directed mutation in the lactose operon in E. coli. This stimulated a fair amount of research into the phenomenon, with the final consensus being that the phenomenon was consistent with neo-Darwinian theory, and the Lamarckian appearance of the phenomenon was an artifact. The literature on the subject is quite rich, and worth looking into for anyone who wants to see what a real scientific challenge to neo-Darwinian theory looks like, and how it is investigated by empirical scientists.

John Wetz, as I've understood the mutation directed debate, there is empirical evidence of the kind of change that you have brought into account, moreover there are example from other topics, e.g the effect of the natural selection over the epigenetic marks, or the genetic assimilation phenomenon, the induced chromosome/genome instability. I think those are great challenge because we cannot translate o reduce them to the classic population genetics formalism (or it's not embraced into the evolution's definition that give that field) or much more important it's going against the gene centered view. But like Ignacio said before, although the empirical/conceptual challenge that represents or mean those phenomena, if they are not ignored, to be partially understandable they are finally translate or reduced to the classical neo darwinian propositions

What kind of empirical evidence or conceptual issues can change the main paradigm of  evolutionary biology?

The notion that all evolutionary biology is a formal science, not a natural science. Its concepts are like statistical concepts based on empirical observations but not real  "themselves. Like the  arithmatic mean in statistics, Even though it is based on empirical things, the mean  does not refer to an external reality.  Neither does the statistical concepts  of differences or changes in the independent variable  that one  one uses in a regression to explain differences or changes in the dependent variable.  Difference and change are physically not real things which also means that natural selection, evolution (change or stasis = no change), or adaptation (in the fitness sense) are  not real either.  They are all defined as differences or changes.

Haven't you ever wondered why natural selection (differential reproduction of genotypes at a locus) is not a force (like gravity) or a process (like the repeated patterns of cause and effect between molecules in photosynthesis) ?

Here is 2 examples showing showing that differences or changes are not real -

example 1  changes 

a circuit with a switch turns a light on or off. The physical state of the circuit can be open - no light is what we sense  or closed - light  (photons) are what we sense.  

What state of the circuit is associated with the "change"  ?  Answer - no such external state exists because  "it"  is a product of conscious perception, not an external reality.

example 2  

All physically real things have a location.

I am physically real and I live in Philadelphia 

My son David is real and he lives in New York City

I am  5' 10"  David is  5' 11'   there is a 1 inch difference in our heights.

In what city does the difference reside?  Answer - nowhere, it does not have an external location,  it is a product of conscious perception, not an external reality.

I don't know about you, but to me this blows away how we understand what evolutionary biology is as a discipline - it is not about cause and effect and none of its concepts are externally real. It is like statistics, a formal science. Functional biology is the only natural science in biology 

Telling other evolutionary biologists the above has disturbed them all and made some of them ill.

I looked at this question a while ago, and have now returned to it. It is fascinating that there are relatively few answers, and that big hitters in evolutionary biology have not weighed in (Wertz is an honorable exception). It is worth remembering that even Darwin himself did not claim that natural selection was the whole and complete explanation of evolution. I think that we can get too hung up on giving current thinking on evolution a name (Neodarwinism), and then reifying  the mix of ideas that it encompasses. I think that  Leonard Greenfield's answer is particularly unhelpful here. I am guessing that it reflects the "linguistic turn" in philosophy and literary criticism (Lacan, Derrida and all that crowd, to distort Tom Lehrer). There are some quite powerful refutations of this approach (see anything by Raymond Tallis, specially "Not Saussure"). Evolution has happened/is happening. There are plenty of examples of natural selection, and of other processes. Should I worry if we find that there are second order processes affecting the frequency or character of mutation/ genetic assimilation/epigenetic effects? Sorry, it does not keep me awake at night.

The problem with Darwinism in general is that it has been characterized as a theory when in fact it would be a research program (PI) or a theoretical network. If we consider the first case (PI), the hard core would consist of a strong hypothesis, ie, "natural selection". And here it is the greatest weakness of this explanatory system as there are many definitions of natural selection that do not coincide with each other. In addition, coinciding with the above, it is conceptualized the natural selection as "process" and/or "mechanism". These characterizations are contradictory because if something is a mechanism cannot be a process. Both concepts have different characteristics. Therefore, natural selection in these terms seems to be a concept untestable or, if you prefer, metaphysical. Should be remembered that the numerous demonstrations of this principle -the natural selection- in the scientific literature, are interpretations of a hypothesis which could not be clearly defined. Obviously, the epistemological problems arising from this situation are endless. Therefore, to conclude, I see no need to seek to replace the darwininsmo theory, I think we just need to build a theory that considers and integrates the myriad of biological concepts currently available.

Cameron's observations about my answer have missed the point - my training and all of my publications are   in evolutionary biology, not philosophy or cultural anthropology. My point was that if we are in the natural sciences, then the phenomena we discuss must be real things external to the viewer -  and real things have certain properties we can all agree on -  like having a location, which differences do not, and other directly measurable  physical aspects. Cameron's dismissal is not based on a refutation of what I said but only an incorrect association with a philosophy that I do not share. Cameron should explain why differences should be considered  real and causal rather than use a straw-man approach to dismissing what he doesn't like. If he was a reviewer of an article proposing this idea, the editor would likely not consider his subjective response to be valid or useful.  

Difference has no location, and change (difference over time) has no directly measurable properties.  Differences cannot cause effects in things and selection, as well as adaptation (in the fitness sense), and evolution (difference over time ), are all defined as differences.  In addition, the neurophysiology of extero-receptors, not usually  a component of thinking on this subject by philosophers, shows that they respond to real things - quantities of photons, pressure waves (hearing) , quantities of molecules , and so on, not difference in photons, or differences in pressure waves,  or differences in molecular concentrations. This unbiased neurological equipment - generating first order neural currents- do not respond to differences because they are not real. We create the notion of difference in second order and higher neural currents so that these concepts may be apparent to us in conscious perception  but sensory neurons  responding to what is externally real reveals that   these thoughts are the later products of our nervous systems - this is not philosophy but an examination of the physical systems that produce thoughts.

Evolutionary "phenomena" are not phenomena - they are like statistical concepts like the mean and variance, and co-variance. Associations between differences in X to explain differences or changes in Y in regression analysis (not philosophy either) are, correctly,  not considered causal   by statisticians. In contrast, evolutionary biologists treat  differences in reproductive outputs between different genotypes at a locus to be causal explanations of differences over time ( changes in allele frequencies or means for complex traits  or stasis (i.e., no change in allele frequencies or means).  This is one of the reasons why evolutionary biologists can't agree on a description of natural selection as a force or a process - it is neither because it is like the mean - based on real objects but not externally real itself.

I am not surprised that Cameron  uncritically accepts a traditional way of thinking as correct, as I had done for 30 years. This means that it will be physiologically  stressful to think of an alternative that negates a concept central to much of what he believes. Kuhn wrote about the resistance to paradigm shifts in his book on the subject - the same resistance  occurred during  the replacement of Newtonian physics (which is still taught in physics 101)  with Einsteinian physics. I am suggesting that  evolutionary biology, after 160+ years, is in need of a similar shift and my argument is backed up by a critique and rejection of current practice. If we are going to be natural  scientists, we must use real things in causal explanations - the concepts of evolutionary biology, looked at critically, do not have the properties of  real things  nor are they causal. They resemble statistical concepts of the  formal science of  statistics.  

Thanks for the response! I fear there is no meeting of minds here. Genuine apology for the evidently mistaken assumption re literary theory, but the argument about difference seemed to have something in common with what  I understand to be a part of Lacanian theory.

"In contrast, evolutionary biologists treat  differences in reproductive outputs between different genotypes at a locus to be causal explanations of differences over time ( changes in allele frequencies or means for complex traits  or stasis (i.e., no change in allele frequencies or means). "

Sure, I can't argue with that, but equally, I do not see it as problematic. In studying real cases rather than just an abstract population genetics equation, the differences are not abstract. Rather (and this can be shown in particular cases), it is the case that form A has a better reproductive/survival chance than form B. both forms are real. Sometimes, we can even pinpoint the particular feature that favours one over the other.

What, in your view, does cause changes over time? I think my physiology is pretty robust, thank you! Quite a lot of my earlier work was a challenge to a "panselectionist" view of evolutionary change at the micro-level. A new paradigm, if you have one, will be exciting rather than intimidating. Bring it on.

Why should it be?

Juan Ramón Álvarez. Simply because if it cannot be refuted, it means that this is not scientific. I do not think that the inquirerer says that darwinism necessarily has to be rejected (may be, Aimer would like it, but it is not what he requested) but it has to be falsifiable to be considered Science. But, as other answered here, I also think that darwinism is methaphysical matter, the nucleous of a program of investigation (PI); a clear example of Khun and Lakatos theories. It impelles other empirical knowleadge but it is not positivist itself.

Ignacio Peñín:

 My question-answer was a quest of explication for a question formulated thus: “How could be the Neo Darwinism distort(ed) or refuted?” It seems not only a question of refutation as a decision procedure about scientificity; to distort is quite a different thing. Your parenthesis points in the right direction “(may be, Aimer would like it…)”. If you set aside distortion, and stay, as you do, fast on refutation you go right into the Popperian and Postpopperian outlooks. The question lies in whether these are the best approaches about scientificity. But I didn´t mean to go so far, I just wanted get straight the point on distortion. That Neodarwinism may play the role of a Research Program, and to that extent that it is a metaphysical frame that, as you say, impels empirical knowledge, is another matter of more philosophical import. It is worth a more detailed and deep discussion. Thanks anyway.

I agree with you point about the distorton, Juan Ramón, it is  probably not the best word for the question or, in fact, it is, but inconsciously. Even, I did not pay attention to the linguistic meaning of distort, I think it is a lapsus as I suppousse (for our names and last names) we three are not English-native speakers. 

I have consider the question in the other way, refering to the question in the explanation: What kind of empirical evidence or conceptual issues can change the main paradigm of the evolutionary biology? I am "Lakatos' supporter" so, yes, I am part of postpopperian points of view; due to that, I think that it is crucial to stablish the way a paradigm can be refuted and, may be, and, because of that, we focused in different part of the question. 

Thank you, too.

There is nothing to blame in being a Lakatos’ supporter, as long as a practicing scientist as you (or Aimer Díaz) are convinced that Lakatos’ theory of Research Programs is the best option for an analysis of the scientific status of Neodarwinism or other such a theoretical frame. I would appreciate to know from you the reason (or reasons) why you find adequate a Research Program as something that may be refuted or, at least, evaluated –I think the second is more feasible. Philosophers of science have been distinguishing between broad frames (metaphysical programs, paradigms, research programs, research traditions, and so forth) and narrower constructs: e.g. Kitcher opposed theories to theory versions -the former being the broad frames, the latter the narrower construct. Broader frames may be evaluated, narrower ones are, if at all, nearer to refutation. Philosophers of science ought to take into account what scientists take as, to employ Popper parlance, falsifiable. These are merely some ideas on passing.

Actually, I can think of one thing that might change evolutionary biology. If we were to discover life on other planets. depending on the complexity of that life, it would lend support to the old design arguments. In many ways the search of E.T. is a search to validate the design argument. Thus the search for E.T. could be interpreted as a search for God. 

"For example the phenomenon of genomic imprinting, or other experimental results, (already succesfully replicated and recognized) are completely Lamarckists and incompatible with Darwinism of any flavor."

I disagree that imprinting is completely Lamarckian. I'm hearing it a lot but I don't understand why the ontological priority of the gene isn't considered more carefully.

Although imprinting does involve back-transfer of information from non-DNA to DNA sources, this makes it contrary to the "central dogma of molecular biology" (which I'm unsure is foundational to neo-Darwinianism) but not necessarily contradicting Darwin.

This is still an example of a heritable trait, and the variation in the trait is no longer completely random but due to environmental factors. It's not as if the environmental factors can modulate the traits (gene expression) without the traits already existing.

Convergence is used as an arguement against gould.