Dr. Ray Greek Condemns Use of Chimpanzees for Medical Research


My Comments to the Committee Evaluating “The Use of Chimpanzees in Biomedical and Behavioral Research”

My name is Ray Greek and I am a physician, board certified in anesthesiology and licensed in the state of California, with over 20 years of experience studying the differences among species in response to drugs and disease. I have taught at the medical schools Thomas Jefferson University in Philadelphia and the University of Wisconsin at Madison. I have authored or coauthored five books on the subject of using animals in science and research and numerous articles in the peer-reviewed and indexed scientific literature on topics including the science of animal-based research, regional anesthesia, anesthesia for vascular anesthesia, pain management, and the philosophy of science (see appendix 2 for publications).

I thank the committee for accepting my comments.

I commend the committee for focusing solely on the science behind the concept of using chimpanzees in research designed to further human health. I am the president of the 501 (c) (3) Americans For Medical Advancement (AFMA) (www.AFMA-curedisease.org) which has focused for over a decade solely on the science of using one species to predict drug and disease response in another species. We believe that the science of using animals in research and testing should be thoroughly addressed before the emotional and contentious discussion of ethics begins.

The AFMA board consists of vegetarians and people that eat meat, scientists who have no ethical issues with using animals in research and scientists that do, animal lovers and some who are ambivalent about animals in general. Historically, society has been spared many emotionally distasteful discussions over ethics and or funding because the science either informed society about the problem thus eliminating some aspects of the discussion or negated the issue altogether as the subject was shown to be scientifically impossible or impractical. I submit that this will prove to be the case in any informed and honest discussion about using chimpanzees in research designed to produce cures and treatments for humans.

Science in general can be divided or classified in many ways but most relevant to this discussion is the breakdown of science into the two categories: theory and empirical evidence. When scientists perform research in laboratories they are usually generating empirical evidence to support or refute a hypothesis. Empirical evidence, also called data, can be generated in other settings such as hospitals and clinics where patients are evaluated for the effects of interventions such as cancer treatments. Empirical evidence is used to decide which of two treatments work better, to determine the average survival times for patients with terminal diseases, to determine which hypothesis is best supported by the data, and so forth. Many a hypothesis has been destroyed by empirical evidence.

The burden of proof in science, as a consequence of the null hypothesis, is on those making the claim. The null hypothesis states that chimpanzees should not be able to predict human response. Researchers advocating for their use in biomedical research claim that they can be so used. In this case, the burden is on those who state that chimpanzees either have been necessary for past breakthroughs or that scientists must use chimpanzees because they predict, with the level of accuracy required in medical science, what will happen in a human when exposed to a drug or disease. Testimonials from people who have a financial or other vested interest in the process is not evidence and certainly is not science. Even historical claims must be proven before they can be taken seriously and such proof is not merely one authority or group of authorities testifying to their version of the facts. There is a reason the argument from authority is known as a fallacy.

Empirical evidence allows us to examine the claim that chimpanzees can predict human responses to drugs and diseases; in other words, that scientists must perform research on chimpanzees in order to find a vaccine against HIV or treatments for neurological diseases. The word predict has a very specific meaning in science, occasional correlation of results does not fulfill the requirement. (Perform any activity often enough and one will find correlation with other events.) In order for a modality or practice to be considered predictive in medical science it must arrive at the correct answer a vast majority of the time. Chimpanzees, when used to model humans for drug and disease research, get the answer wrong more often than not. Thus, chimpanzees have been shown, empirically, unable to predict human response to drugs and disease (Shanks and Greek 2009; Shanks, Greek, and Greek 2009) counter to the claims of those wishing to use them in research and testing.

Perhaps the best empirical evidence that chimpanzees will never be predictive for human response to drugs and disease comes from the study of humans. It is now a well-established fact that even individual human individuals respond differently to drugs and diseases. Most drugs work very well for some but not other humans. Diseases affect men differently than women and different ethnic groups are more predisposed to specific diseases than others. Even monozygotic twins do not always react the same to disease and medication. If other humans fail to this degree in predicting disease and drug response, why should any reasonable person hope to find these answers in a different species? Inter-species differences are intra-species differences writ large. Trying to obtain answers from a different species is going in the wrong evolutionary direction.

Theory, on the other hand, is a much more powerful expression of science. A theory can place all the empirical evidence in perspective, make predictions about future developments, and prevent scientists and funders of research from chasing ideas and research that have no hope of success. Theory can explain why the empirical evidence is not an example of cherry-picking data to support one’s position but is in fact representative of reality. The Theory of Evolution is one example. It allows scientists to ask more intelligent questions and look in the appropriate places for answers. The Theory of Relativity is another example. Theories usually revolutionize the scientific discipline they address. Theories need not be named theories to be theories. For example, current knowledge of cell biology leads science to have certain expectations about life in general even though one does not normally hear the phrase cell theory of life. Likewise, current understanding of the physics discipline known as chaos heavily influences our understanding of natural phenomenon, like the weather. One could say that current understanding of chaos provides the theory into which scientists can place the empirical evidence or data of weather. Scientists do not expect weather to behave in a way that is inconsistent with chaos theory.

The use of chimpanzees in research is sold to society on the basis of finding cures and treatments for disease. The thinking is, that if a treatment is effective in chimpanzees, it will be effective in humans or that if it is safe in chimpanzees, then it will be safe in humans. History, in the form of empirical evidence, has shown this expectation to be unrealistic and science in the form of evolutionary biology, evo devo, genetics, comparative medicine, systems biology, and complex systems, has now explained why this is the case. There now exists a theoretical construct to explain the empirical evidence. These two aspects of science have never before been available to those evaluating the role of animal models in research. (Much of this knowledge came directly or indirectly from the Human Genome Project and the subsequent spinoffs.) By using the knowledge gained from the empirical evidence and the theory that supports and explains it, we can confidently say that the reaction to a drug or disease that scientists see in chimpanzees will have little predictive value for humans. There is no value in medical science for something with a predictive value that low. Using it does more harm than good. Chimpanzees cannot be used in research as a basis for human interventions. This is where current science leads us on this important topic and this invalidates a vast majority of the arguments given by supporters of using chimpanzees in research.

(Interestingly, in the UK the use of dogs in research is currently being re-examined and the same points I bring up here are being made in the context of using dogs. From Nature 30 June 2011: “Man's best friend bears a heavy burden in the pharmaceutical industry. Every year, tens of thousands of dogs are subjects in drug-toxicity studies in Europe and the United States, even though many scientists think that they are poor predictors of drug effects in humans.” Emphasis added. The prediction problem is appearing more and more in the scientific literature that examines the use of animal models and will, in my opinion, be how future generations judge us. The question they ask will be: “If they [meaning you who now decide these matters] knew the models were not predictive, why did they continue to use them as if they were?”)

If a practice or modality or a specific research method does not fulfill the goals or claims made to justify it, then that method should be abandoned regardless of what else is available. Bloodletting was abandoned because it did not work, as were many other medical practices, not because cures were found for the conditions for which bloodletting was being used. Discussing the ethics of bloodletting without being informed by the scientific research proving that it was ineffective, and indeed counterproductive, would itself be unethical. Likewise, we do not perform trephination on cancer patients dying from their disease for the simple reason that we know trephination to be ineffective. There are no cures or even treatments for these patients yet we do not drill holes in their head. One does not flip a coin to decide whether to proceed with a new treatment, even though this method would have been more predictive of vaccine success for HIV than nonhuman primates have been. The claims made for using chimpanzees in research is based on prediction and those claims do not withstand scrutiny. Therefore the use of chimpanzees for such purposes should be abandoned regardless of what other research methods are available.

The one area where chimpanzees can be successfully used in research is in basic research. Basic research makes no claims of being able to predict human response to drugs and disease and thus lies outside the arguments being made by those wanting to use chimpanzees in research. Basic research is research merely for more knowledge and that knowledge may or may not (indeed probably will not) lead to treatments or anything else but the knowledge itself. This is not a bad thing in and of itself as knowledge has its own value, but society has not looked favorably upon the use of animals like chimpanzees for such research.(Greek and Greek 2010) When discussing the use of chimpanzees in basic research, ethics does come to the fore. But the claims made by those wishing to use chimpanzees in research fall squarely under the predictive aspect of research not under the category of basic research. It is this claim, that chimpanzees can predict human response, that has been falsified on both theoretical and empirical grounds. No ethical discussion is needed in this area—the science is clear.

In this very short summary I have outlined the difference between theory and empirical evidence in science and have referenced works supporting my position. To actually present the scientific evidence for my position would require a book-length essay. Indeed I have coauthored such a book (see Shanks and Greek 2009). Articles are also available that present the case for my position in more detail than is presented here but in less than is presented in book form (see Greek and Greek 2010; Shanks, Greek, and Greek 2009; Shanks et al. 2007). The book and articles contain hundreds of references to the scientific literature including the fields of evo devo, evolutionary biology, complex systems, genetics, genomics, philosophy of science, and personalized medicine among others. The fundamental scientific principles that must be appreciated prior to examining the value and role of animals in general, and chimpanzees specifically, in biomedical research are not going to be found in a cursory examination of the subject. In my experience, a vast majority of scientists that weigh in on these matters, on both sides of this issue, are simply ignorant of the transdisciplinary science involved and hence the implications. I repeat, testimonials are not science! There is enough solid science available on this topic to come to a confident decision that will withstand the test of time. But only if one avails oneself of that knowledge. I ask that the committee take the time to read the pertinent sources. Human lives are at stake.

I am available should the committee be interested in more information and would be happy to send copies of Animal Models in Light of Evolution if the committee so desires.


Greek, R., and J. Greek. 2010. Is the use of sentient animals in basic research justifiable? Philos Ethics Humanit Med 5:14.

Shanks, N, and R Greek. 2009. Animal Models in Light of Evolution. Boca Raton: Brown Walker.

Shanks, N., R. Greek, and J. Greek. 2009. Are animal models predictive for humans? Philos Ethics Humanit Med 4 (1):2.

Shanks, Niall, Ray Greek, Nathan Nobis, and Jean Greek. 2007. Animals and Medicine: Do Animal Experiments Predict Human Response? Skeptic 13 (3):44-51.

Ray Greek MD

Americans For Medical Advancement (http://afma-curedisease.org)


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