bs_bs_banner

Journal of Evaluation in Clinical Practice ISSN 1365-2753

How the creative use of analogies can shape medical practice G V Ramesh Prasad MB BS MSc MA FRCPC FACP FASN Associate Professor of Medicine, Renal Transplant Program, St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada

Keywords analogy, conservative, creative, domino, medical progress, transplantation Correspondence Dr G V Ramesh Prasad Renal Transplant Program St. Michael’s Hospital University of Toronto 61 Queen Street East, 9th Floor Toronto, ON M5C 2T2 Canada E-mail: [email protected] Accepted for publication: 12 January 2015 doi:10.1111/jep.12334

Abstract Analogical reasoning is central to medical progress, and is either creative or conservative. According to Hofmann et al., conservative analogy relates concepts from old technology to new technologies with emphasis on preservation of comprehension and conduct. Creative analogy however brings new understanding to new technology, brings similarities existing in the source domain to a target domain where they previously had no bearing, and imports something entirely different from the content of the analogy itself. I defend the claim that while conservative analogies are useful by virtue of being comfortable to use from familiarity and experience, and are more easily accepted by society, they only lead to incremental advances in medicine. However, creative analogies are more exciting and productive because they generate previously unexpected associations across widely separated domains, emphasize relations over physical similarities, and structure over superficiality. I use kidney transplantation and anti-rejection medication development as an exemplar of analogical reasoning used to improve medical practice. Anti-rejection medication has not helped highly sensitized patients because of their propensity to rejecting most organs. I outline how conservative analogical reasoning led to anti-rejection medication development, but creative analogical reasoning helped highly sensitized and blood type incompatible patients through domino transplants, by which they obtain a kidney to which they are not sensitized. Creative analogical reasoning is more likely than conservative analogical reasoning to lead to revolutionary progress. While these analogies overlap and creative analogies eventually become conservative, progress is best facilitated by combining conservative and creative analogical reasoning.

Introduction The problem New technology assists health care providers perform their roles. Technology first needs to be developed and then properly understood by those who are going to use it [1]. In this essay, I will focus on how new medical technology is developed and comprehended through analogy, by using as my example technology’s impact in increasing the overall success of living donor kidney transplantation, with its dual goals of making kidney transplants work better and increasing total transplant numbers. Solid organ transplantation (kidney, heart, liver and lung) is an established therapy for patients with end-stage organ failure. New anti-rejection medications as a technology are important to increasing transplantation success. Rejection of the transplant rapidly leads to its failure if untreated and the patient becomes seriously ill and may even die. Even if treated, the organ’s function

may remain suboptimal, leading to prolonged illness, and the patient experiences serious side effects from the same or added medications administered in high doses. As medications steadily improved in effectiveness, rejection rates in kidney transplantation have substantially decreased. When rejection does occur, it is now treated more effectively. Potential recipients at risk for rejection can be predicted more reliably based on the presence of preformed antibodies in their blood, and so their medication is planned accordingly in advance. The majority ‘first group’ of patients, i.e. those reasonably sure to get a transplant, has greatly benefitted from the new technology. There is, however, a significant number of patients who are rarely transplanted because they are ‘highly sensitized’. This means that they have antibodies against most potential donors and are very likely to quickly reject any organ. The initial ‘cross-match’ done before an available organ is allocated almost always shows a reaction, and so the potential recipient is never offered the organ, knowing it will be rejected. These sensitized patients (‘second

Journal of Evaluation in Clinical Practice 21 (2015) 455–460 © 2015 John Wiley & Sons, Ltd.

455

Creative analogies in medical practice

group’) may die waiting because all advances in anti-rejection medication technology have not helped them. Related to them are those who have a living donor but that donor’s blood type is incompatible. Patients of certain blood types (e.g. blood type B in Ontario, Canada) languish on very long transplant waiting lists for a deceased donor to become available for them. Analogical reasoning has effectively been used when developing and understanding new anti-rejection medications, greatly benefitting the first group of patients, but not the second group.

Conservative and creative analogies in medical technology Analogy is the process of understanding a novel situation in terms of one that is already familiar [2]. It is a powerful cognitive mechanism used to make inferences and learn new abstractions [2]. The familiar situation (base or source analog) is a model used to infer about an unfamiliar situation (target analog) [2]. Knowledge is thereby represented in an explicit form, and by doing so, systematic comparisons can be made between these two distinct domains. A key function of analogy is to understand a new situation with the help of a familiar situation [2]. Understanding involves a transfer of meaning from the source analog to the target analog. When an analogy is used conservatively, it means that any concepts relating to the new technology are based on the old technology; when the old analogy is part of the widely established practice, this means that old norms of comprehension and conduct and their related practices are preserved as far as possible. New technologies are thus made to ‘fit images of existing technologies’ [1]. When an analogy is used creatively, on the other hand, it produces concepts that are quite different from the analogies that established them, brings in similarities from one area to another where they had never been used before and may bring with it something altogether different from the content of the analogy itself, called a ‘figurative function’ [1]. Therefore, conservative analogies more closely correspond to what is already known and established, while creative analogies do not, often in more than one way. In addition, with conservative use, the source analog domain is closely related to the target analog, and being usually wellestablished, may have been used as a source analog in other analogies before. With creative use, however, the source analog may belong to a domain quite distant from the target. The source analog may also be used for the first time or a particular similarity may be transposed from a source domain into a target domain where it was never used before. Analogies can be used both conservatively and creatively in the context of transplantation. For example, a blood pressure medication such as diltiazem is used in transplant recipients for blood pressure control after already having been successful in nontransplant patients and found to be effective for that purpose even though the mechanism for hypertension was different. This is conservative analogical reasoning. On the other hand, the same blood pressure medication when first used in transplant patients with no blood pressure reduction need, but instead specifically for a known drug interaction of diltiazem with cyclosporine that allows for using a lesser dosage of the more expensive cyclosporine, is creative. In other medical situations, this interaction is a nuisance and potential danger, but in transplantation it is 456

G.V.R. Prasad

useful. This is creative analogical reasoning because of its figurative function [1]. Both types of analogies are useful and complementary to each other. They may also overlap. A given analogy can be used either conservatively or creatively depending on the situation, but creative analogical reasoning can take over in instances where conservative analogies do not provide a solution.

Structure of argument I make the claim that while conservative use of analogies is helpful, creative use of analogies leads to more progressive implementation of new technology to improve overall kidney transplantation success. I will first outline the history of anti-rejection medication over the past 60 years and show that the conservative use of analogies has led to important but incremental advances, in some instances has caused actual harm to patients, and eventually meets insurmountable obstacles. Next, I will show that using analogy creatively instead allows for greater technological advance, perhaps revolutionary, especially when serious obstacles are encountered in medicine with conservative analogical reasoning. Finally, I will discuss why I think creative analogies are more helpful when conservative analogies fail and conclude that conservative and creative analogies can work together to facilitate medical progress.

Creative versus conservative analogical reasoning Conservative analogical reasoning in transplantation Kidney transplants have been regularly performed since the 1960s but there is an important preceding history. The first successful transplant occurred in 1954 between identical twins, a case in which anti-rejection therapy was not needed. Radiation as x-rays was a known ‘medication’ at the time for leukemia when followed by a bone marrow transplant and was needed to prevent graftversus-host disease. Irradiation was also used in initial attempts by analogy to extend bone marrow transplantation to other organs. In 1959, a beagle was irradiated, given bone marrow cells from its potential donor to induce ‘tolerance’ (i.e. no anti-rejection medications needed) and then given a kidney transplant. The beagle lived and the transplant was deemed a ‘success’ [3]. By 1962, eleven human patients had received whole body irradiation prior to transplantation but with one exception, ‘mortality was virtually complete’ from sepsis [3]. Conservative analogical reasoning held that recipient responsiveness to the organ could be enhanced in humans as in the dog by curtailing graft-versus-host disease. However, sepsis intervened in humans before this could be verified. Irradiation as a therapy was abandoned. The next major development was the introduction of corticosteroids and azathioprine. Corticosteroids were used in diseases involving steroid deficiency and auto-immunity and by conservative analogy to transplantation. A number of side effects (e.g. weight gain, diabetes) were seen in transplantation, similar to other conditions, but deemed acceptable. Azathioprine’s story (1960– 1963) is more interesting. The anticancer drug 6-mercaptopurine was found to inhibit antibody responses in rabbits to beef protein. It was found to be unacceptably toxic when used for animal

© 2015 John Wiley & Sons, Ltd.

G.V.R. Prasad

kidney transplants, but azathioprine, a chemical analog of 6-mercaptopurine, showed great promise. When azathioprine was successfully combined with corticosteroids based on dog models of acute rejection therapy, the ‘genie was out of the bottle’ and this combination was then used for the next 20 years [3]. Analogy was thus used conservatively when extending animal models to humans (as with irradiation), drug efficacy in other diseases to transplantation, searching for effective molecules closely related to the prototype and using existing drugs in combination. The next ‘pair’ of drugs studied was cyclosporine and tacrolimus. Although cyclosporine came first, both drugs are still widely used. They have similar mechanism of action, inhibiting a key intracellular enzyme called calcineurin phosphatase responsible for activation of lymphocytes, which are cells that cause rejection. By conservative analogy, tacrolimus was compared with cyclosporine and found to be equally effective at preventing rejection. Yet the side effect profile proved to be quite different. Cyclosporine caused hair growth and tacrolimus hair loss. Cyclosporine caused more hypertension and excess gum growth, while tacrolimus caused more diabetes and neurotoxicity. This real-world example shows how disanalogy invariably appears once experience is gained. Finally, sirolimus is an anti-rejection drug structurally related to tacrolimus but not cyclosporine. However, sirolimus has a different mechanism of action from either (it is an ‘mTOR’ cell cycle inhibitor, not calcineurin inhibitor). Through clinical trials, it was found to be toxic to the kidney when used with cyclosporine but not when used with tacrolimus. While it was found to be very effective in kidney transplants, it was unexpectedly found to be very toxic in liver transplants (unlike the other drugs) by causing hepatic artery thrombosis. Immunosuppressive drug advances have greatly contributed to transplant progress, helping many patients. However, serious complexities cannot always be predicted in advance by conservative analogical reasoning, as the available data may be insufficient. Therefore, with enough time and experience, conservative analogy invariably leads to disanalogy (of varying degrees of importance) in medical practice.

Strengths and weaknesses of conservative analogical reasoning Conservative analogies are very comforting to use. They are founded on familiarity and experience. The source analog originates in a domain close to the target analog and is typically already quite familiar to the concerned audience. The source analog is easily recognizable to most people, and in the case of medical technology, is backed by corroborative high-quality evidence that supports its use as a standard, fit for comparison with newer technology. It can be easily retrieved. The source analog’s technology has developed behind it a robust scientific basis for its use and is widely popular for that reason. The source analog may have also been successfully used before when a previous new technology had been introduced. With conservative analogy, there is no change in the meaning intended because old concepts are ‘brought to bear on new ones’ [1]. This means that basic mechanisms and function within each domain are assumed to be the same. Conservatism is reinforced by society when medical guideline committees are constituted to determine how the new technology is to be used; when most members are familiar with the source analog

© 2015 John Wiley & Sons, Ltd.

Creative analogies in medical practice

and can understand the mapping to the target, there is little challenge to use of that analogy by experts or non-experts. There is little loss of meaning, implying that the original meaning remains easily recognizable. No further interpretation becomes necessary and understanding is quick and efficient. Science is socially situated rather than insular and so existing societal constraints are satisfied. Conservative analogies are thus readily persuasive. With anti-rejection medication development, conservative analogical reasoning is not only ideal, but required for regulatory approval of new drugs because they need to be compared with existing, effective drugs for safety and efficacy. Safety is extremely important in the case of human subjects. The safety profile is in turn compared against any incremental increase in efficacy, but safety comes first. There should certainly be no decrease in efficacy and no safety ‘signals’. The existing standard of care is now so high that any advance in drug therapy can only be incremental. Large sums of money are committed by funding agencies, which are run by non-experts, who need to understand the comparisons being made. Conservative analogical reasoning is thus the best way to proceed because the social constraints on science are satisfied. Anti-rejection drug therapy has progressed significantly over the past 60 years, from irradiation to the present day potent multidrug combinations. Despite these advantages, conservative analogies have some limitations. Much is epistemically lost when analogies are used in a predominantly conservative manner. Failure to recognize the level of depth or sophistication in the underlying science, or ignoring relevant parts of it, may lead to a failure in transfer of meaning of the analogy and loss of its explanatory function. This can happen when medical professionals underestimate the complexity of the source domain and/or target domain because of their conservative intention. Oversimplified comparison of features within each domain can lead to fundamental loss of scientific understanding. If an intended conservative analogy ultimately shows disanalogies, this means that relevant features were either ignored or previously unknown. Trusting non-experts may be seriously misled. Conversely, if the intended audience is sophisticated or already conversant with the relevant issue, little is gained in terms of understanding in the scientific community. The analogy is, in other words, superficial [4]. Eventually, any utility of conservative analogy is exhausted because it has reached its limit. Worn-out analogies also prevent the use of new ones, limiting their use as teaching aids [5], as has been adequately illustrated in the case of anti-rejection drugs. Prednisone is still used after 60 years despite its numerous side effects because it is still included in most successful drug combinations based on the limitations of conservative analogical reasoning (e.g. if prednisone being part of one immunosuppressive medication regime is successful, then using it in another type of regime will also be successful).

Creative analogical reasoning in transplantation To reiterate, according to Hoffman et al. [1], there are three characteristics by which creative analogies can be distinguished. First, with creative analogies, the understanding of a new technology is quite different from the analogy that established it. The existing technology may have been from a completely different domain of science or medicine and the new concept behind it is quite 457

Creative analogies in medical practice

different from the analogy that established it. Second, creative analogies bring similarities that exist in the source domain to a target domain in which they previously had no bearing. The existing technology, in other words, has no clinical relevance in the context of the new technology. Third, these analogies have a ‘figurative’ function, which means that there is something imported to the target domain which is entirely different from the content of the analogy itself, going beyond literal similarities [1]. To sum these up, creative analogies ‘create’ new use of technologies. As mentioned previously, there remains a large number of patients who are very difficult to transplant (the ‘second’ group) because they will promptly reject any organs offered to them even if they have a living donor. We will now focus on these patients. All the advances in anti-rejection drugs cannot help them because when the transplant will occur cannot be predicted (we cannot know when a potential donor will die) and it is not ethically feasible to continually prepare such a patient for a transplant with powerful short-acting anti-rejection drugs indefinitely. The newer drugs by themselves have thus failed to help the 10% or so of patients who have preformed antibodies against most of the population. This is a serious obstacle in transplantation medicine because conservative analogical reasoning has not helped to find them organs because of the limitations of the available supply. There is no source analog nearby (other organ transplant types, immunosuppressive medicines from other areas) that can be used to find a solution. This is where creative analogical reasoning is extremely helpful. Montgomery et al. [6] published their experience with ‘domino paired kidney donation’. Suppose there is a set of donor–recipient pairs (donor 1, recipient 1; donor 2, recipient 2; donor 3, recipient 3) but donor 1 cannot give a kidney to recipient 1, donor 2 cannot give to recipient 2 and donor 3 cannot give to recipient 3 because of a variety of medical reasons that anti-rejection drugs cannot solve (e.g. pre-formed antibodies or blood type incompatibility). Now an altruistic kidney donor comes along, one who is willing to give a kidney to anyone. This kidney used to be given to a single recipient at the top of a transplant waiting list (recipient 4). One transplant has been performed but donor–recipient pairs 1, 2 and 3 languish. Instead, Montgomery et al. gave the altruistic donor kidney to recipient 1, donor 1 gave a kidney to recipient 2, donor 2 to recipient 3 and donor 3 to recipient 4. As a result, now four transplants have been performed instead of one, quickly and efficiently, with the same single altruistic donor at hand. It is a ‘domino’ transplant. Dominos is a game whose parts include multiple rigid boards. These boards can also be placed upright in close proximity on a flat surface in very sophisticated patterns. When one board is knocked down, all boards topple in quick and orderly succession in a chain reaction. This analogy is creative because the source domain (a board game) is far removed from the target domain (kidney transplantation). Applying Hoffman et al.’s criteria [1] to creative analogies, an understanding of how dominos topple is important to understanding how a domino chain works in principle, but other subtle technical aspects to make the transplant chain work (travel time, finding donor–recipient pairs, order of the transplants in the chain, organ preservation, consent, etc.) have nothing to do with the perhaps equally sophisticated rules involved in knocking down dominos. The chain of succession with dominos falling had no previous bearing in kidney transplantation. Finally, 458

G.V.R. Prasad

something new is brought into the target domain independent of the content of the analogy itself: more transplants are performed, patients who could not be helped previously with anti-rejection drugs alone are now being helped, and finally, altruistic donors derive greater satisfaction from being able to help a greater number of people with a single act. Extra-powerful anti-rejection drugs are no longer needed. Standard medication is enough. A major stumbling block in transplantation has been overcome. Nowadays, domino transplants have been extended to other organs and different countries. With time, creative analogies thus become conservative and eventually simple thoughts. Probably, many conservative analogies were creative at some point in the past. For example, the first creative organ ‘trans-plant’ occurred in an animal model rather than a plant, but this fact is now scarcely recognized. The first blood bank was a creative analogical model, in which blood was handled in the same manner as monetary deposits and withdrawals. Biobanks became conservative analogical extensions, and the original source analog, the monetary bank, does not come to mind [1].

Strengths and weaknesses of creative analogical reasoning Creative analogies of course deserve the same scrutiny as conservative analogies. Their great strength is that they can be used in situations where conservative analogies fail. The advances they provide cannot be matched in time or magnitude by the incremental epistemic advances that conservative analogies provide. Depending on the source domain, creative analogies may actually be more understandable than source domains used in conservative reasoning. According to Holyoak and Thagard [5], there are four uses of scientific analogy, namely discovery, development, evaluation and exposition, with a given analogy having more than one potential use. Creative analogical reasoning may create revolutions different from what Kuhn originally described [7] as they do not occur after the accumulation of anomalies to an existing paradigm, but quickly and directly import something from another domain. Creative analogical reasoning may also lead to less disanalogy with time and experience because greater care is invested up-front studying the target domain ahead of implementation of the new technology. Unlike discovery and exposition which more likely come from creative analogy, development and evaluation fit better with conservative analogy, although such a divide is not always so neat. Most ‘normal’ science consists of incremental advance provided by development and evaluation ‘against the background of the paradigm’ [7]. Any use of creative analogy here is more likely to lead to blind alleys, with wasted effort and resources because there is less supportive underlying data. An entire research programme may be devoted to looking for revolutionary advances and come up empty in the end. Using the Lakatos analogous model of a research programme’s ‘hard core’ and ‘protective belt’ [8], it seems that creative analogies can strike at the ‘core’ while conservative analogies focus on the ‘belt’. However, hypotheses generated by creative analogies still need testing. Analogy is inherently a risky form of argument that can lead to false conclusions [5] and creative analogy may be especially so. Publication bias tends to highlight only successful creative analogies, so it is possible that many failed creative analogies did not reach exposition. Conversely,

© 2015 John Wiley & Sons, Ltd.

G.V.R. Prasad

results from using conservative analogies are more likely to get published, being from a more proximal domain, and they can help navigate further incremental research within the programme. Creative analogies may have a further dark side. If greater care is not invested up-front before implementation, when patients are involved, creative analogies can lead to just as much subsequent disanalogy.

Why creative analogies are helpful where conservative analogies fail So far, we have discussed the roles conservative and creative analogies play in medical progress. Now, we will discuss why it is that creative analogies are more useful in certain situations, such as when conservative analogical reasoning reaches a major stumbling block. Gentner [9] proposed the ‘structure-mapping’ theory as a framework for analogical reasoning to show how the meaning of an analogy is derived from the meaning of its parts. According to this theory, a set of rules is put in place to map knowledge from source (base) domain to the target domain, thus distinguishing analogies from other kinds of comparisons. It is relations between targets and not physical attributes of the objects themselves that are mapped from base to target and the particular relations mapped are determined by ‘systematicity’, which depends on ‘higher-order’ relations [9]. In other words, elements in the source domain are more likely to be mapped to the target domain based on their relationships to other elements in that domain, than on what the elements actually are. In an analogy, the object attributes are few, but the number of relations mapped to the target may be many, and these relations have priority over object attributes [9]. Some of these relations are themselves inter-related, leading to higher-order relations, and systematicity dictates that objects in such relationships with other objects are more likely to be mapped to the target domain [9]. A simple example will help to illustrate these points. Galesic and Garcia-Retamero [10] elucidate the example ‘a lion is among animals (target) as a king is among humans (base)’. Lions and human kings have very few physical attributes in common, apart from being terrestrial mammals. Yet the analogy is readily understood and effective because the relationship between lions and other animals within the target domain is similar to that between a king and his human subjects. Both naturally exert power over others, are capable of violently harming others and therefore garner their reverence and are vociferous when their needs are not met. It is the functional attributes which make the analogy more effective, rather than the feature similarities [10]. Higher order relations such as ‘tyrant’ and ‘fearsomeness’ which combine these attributes are also systematically added making the analogy more effective, despite modern disanalogy (lions are easily killed by ordinary humans and most kings are now figureheads). When unexpected connections are made across distant domains, the human mind is excited. This is the source of much humor, as well as creative discovery. Now let us see how this applies to kidney transplantation. The domino transplant, our creative analogy example, fits very well because it is the function of the dominos that is being mapped to the transplant chain, rather than the features of the flat domino boards with dots on them. A fallen domino is deemed a success,

© 2015 John Wiley & Sons, Ltd.

Creative analogies in medical practice

just as a completed transplant. The order of the dominos and the transplants is predetermined. The boards are designed to be of the right size and similar size, just as the transplanted kidneys must be similar qualitatively, and the operations are performed very soon after each other. The functional similarities thus far outstrip the physical similarities. This is compatible with Gentner’s structuremapping account, which emphasizes relations between the targets. Transplant drug development, by contrast, fits less well. Drugs are initially developed based on chemical similarity, but as shown in the tacrolimus-sirolimus example, the analogy does not map very well because function can turn out to be very different. Even though cyclosporine and tacrolimus are chemically quite different, they are functionally more similar and are managed accordingly by physicians and patients. Also, when considering organs that can be transplanted other than the kidney, a liver does not look like a kidney, and a heart does not look like either. However, functional similarity can be used to derive a logical system of anti-rejection treatment for all organ transplants. This is in keeping with functional relationship similarity being more important than physical similarity. Structure-mapping supports my claim that creative analogies can be successful when conservative analogies fail because medical therapeutic success inherently depends on doing things for patients (host). In turn, medical therapy is an active process dependent on the functions of body parts, their interactions with each other and their interactions with specific external agents (drugs, organisms) and the environment. All these relationships provide room for creativity. Conservative analogies based on physical similarity alone (as in this example) will work only when other factors are constant or predictably vary within a narrow range. A classification compatible with system mapping has been proposed by Blanchette and Dunbar [4], according to which there are two types of similarity in analogical reasoning: superficial and structural. Superficial similarity refers to resemblance between objects in the source and target domains in their physical appearance and properties, while structural similarity refers to the relations among the objects within each domain. Through a series of experiments, they showed that educated subjects are more likely to generate source analogs based on structural similarity, but when presented with a series of potential source analogs to a given target analog, were more likely to select one based on superficial similarity [4]. Scientists are by nature explorers. Conservative analogies are essentially more ‘superficial’ as shown in the antirejection medication analogies, while creative analogies are more ‘structural’, as shown in the dominos analogy. Creative analogy functions more outside of society, when one scientist ‘just does’ an experiment and reports it later. Society is more comfortable with conservative analogies. Thus most creative analogical projects originate at single research centres with minimal advertisement, and after initial success, other centres are added as the analogical reasoning transforms conservatively. Creative analogies are based predominantly on structure while conservative analogies are superficially applied hoping that structure will be compatible. Holyoak and Thagard’s [5] constraints of structure, similarity and purpose work well for understanding the conservativecreative distinction, just as both Gentner’s [9] and Blanchette and Dunbar’s [4] accounts are helpful. According to Holyoak and Thagard [5], ‘analogical thinking is sensitive to the purpose 459

Creative analogies in medical practice

for which the analogy is being used’. Inherent limitations of conservative analogies in modern medicine usually block the move to making them creative. It is possible that some problems can be addressed by employing those same analogies creatively, as in the diltiazem example, when new technologies such as transplant are developed and allow for such opportunities. Such analogies eventually become just simple thoughts. Instead of creative analogies becoming conservative, conservative analogies could become creative.

Summary and conclusion New technology needs to develop in medicine and be properly understood by those who are actually going to use it. New antirejection medications as a technology are important to increasing transplantation success. Most patients benefit from these medications. Conservative analogies have resulted in enormous progress in medications over 60 years, but not for the small but significant proportion who are highly sensitized because they will reject most transplants. The brute force of anti-rejection medication is useless or at best, of very limited utility for these patients. However, creative analogy, such as performing domino transplants modelled after dominos falling, has actually helped by finding for them kidneys from compatible donors, while performing multiple transplants with help from a single altruistic donor. Creative analogical reasoning can be used both as a teaching tool and an experimental method, with perhaps greater value as a teaching tool. A creative analogy allows the mind to see past the basic intervention and think about how to make an application relevant. Also, noticing impacts or irregularities in practice can potentially be applied to other populations. This contemporary real-world example of domino transplants from the modern history of medicine shows that creative analogies succeed when conservative analogies fail because creative analogical reasoning is better able to take into account functional and relational similarities, consistent with the structure-mapping theory, than conservative reasoning does. It also takes into account structural rather than superficial similarities, and more likely results in revolutionary scientific progress because it emphasizes function, minimizing epistemic loss. Relationships within each domain and higher-order relations are emphasized. The human mind is then excited by unexpected connections between vastly different domains, not recognizable superficially, but triggering creativity and novel solutions. Creative analogies appeal more to scientists but conservative analogies better satisfy societal constraints. Creativity and conservatism are not exclusive but also overlap. A given analogy can be used either conservatively or creatively depending on the details of the situation as well as intent or purpose, but creative analogical reasoning can take over where conservative analogies fail to provide a solution. Creative analogies create new uses of technology.

460

G.V.R. Prasad

However, it would be naïve to assume that all the problems of conservative analogies can be addressed by using creative analogies. Examples of creative analogies are rare in medicine. Creative analogies also require greater care because if the domains are distant, the potential for harm may be greater when important differences between source and target analogs are unrecognized. Successful creative analogies eventually become conservative. Conservative and creative analogies should be used together in facilitating progress; conservative analogies are more suited to normal science while creative analogies may be more fitting for revolutionary progress. It is possible that conservative analogies can be employed creatively, but I suspect this will be less common than creative analogies themselves.

Acknowledgements The author gratefully acknowledges Doreen Fraser, PhD, Department of Philosophy, University of Waterloo, Canada, for her extensive comments and guidance in the preparation of this paper.

References 1. Hofmann, B., Solbakk, J. H. & Holm, S. (2006) Teaching old dogs new tricks: the role of analogies in bioethical analysis and argumentation concerning new technologies. Theoretical Medicine and Bioethics, 27, 397–413. 2. Gentner, D. & Holyoak, K. J. (1997) Reasoning and learning by analogy. The American Psychologist, 52, 32–34. 3. Tilney, N. L. (2003) Host defenses and immunity. In Transplant: From Myth to Reality (ed. N. L. Tinley), pp. 83–108. New Haven, CT: Yale University Press. 4. Blanchette, I. & Dunbar, K. (2000) How analogies are generated: the roles of structure and superficial similarity. Memory and Cognition, 28, 108–124. 5. Holyoak, K. J. & Thagard, P. (1996) The analogical scientist. In Mental Leaps: Analogy in Creative Thought (eds. K. J., Holyoak & P., Thagard), pp. 185–209. Cambridge, MA: The MIT Press. 6. Montgomery, R. A., Gentry, S. E., Marks, W. H., et al. (2006) Domino paired kidney donation: a strategy to make best use of live nondirected donation. Lancet, 368, 419–421. 7. Kuhn, T. (2012) Anomaly and the emergence of scientific discoveries. In The Structure of Scientific Revolutions, 50th Anniversary Edition (ed. T., Kuhn), pp. 52–65. Chicago, IL: The University of Chicago Press. 8. Godfrey-Smith, P. (2003) Lakatos, Laudan, Feyerabend, and frameworks. In Theory and Reality: An Introduction to the Philosophy of Science (ed. P., Godfrey-Smith), pp. 102–121. Chicago, IL: The University of Chicago Press. 9. Gentner, D. (1983) Structure-mapping: a theoretical framework for analogy. Cognitive Science, 7, 155–170. 10. Galesic, M. & Garcia-Retamero, R. (2013) Using analogies to communicate information about health risks. Applied Cognitive Psychology, 27, 33–42.

© 2015 John Wiley & Sons, Ltd.

How the creative use of analogies can shape medical practice.

Analogical reasoning is central to medical progress, and is either creative or conservative. According to Hofmann et al., conservative analogy relates...
102KB Sizes 0 Downloads 7 Views