Linguistic threats associated with metaphors about evolution

Linguistic threats associated with metaphors about evolution

Martie Sanders

Abstract

This article deals with several problems associated with metaphors commonly used for scientific concepts associated with the topic of evolution. First, a pragmatic linguistic approach is used to clarify the relationship between analogies and metaphors, about which many authors in the science-education literature express uncertainty. A “razor-wire” metaphor is then applied to discuss the linguistic risks of several metaphors describing aspects of evolution. The razor-wire metaphor expands the metaphor of the “double-edged sword”—used to describe the benefits and risks of analogies in the teaching of science—to a multi-dimensional metaphor which includes three additional linguistic problems: “paradoxical jargon” terms in science; anthropomorphism; and teleology. Thirdly, the use of metaphors by two different groups of people in the sciences (scientists and science educators) for two different purposes (scientific clarification and pedagogical clarification) is discussed, and used to illustrate that even the metaphors used by Darwin (which made his work easy reading for laypeople) were misinterpreted by some of his scientific readers. Finally, likely links between metaphors and common misconceptions about evolution are discussed in terms of two alternative frameworks identified in the research about evolution, based on the metaphors “survival of the fittest” and “adapt or die”.

Introduction

This article outlines pertinent issues relating to the use of metaphors as analogies. The educational benefits of analogies and metaphors are well documented, particularly in the field of science education where analogies are commonly used to explain the unfamiliar, difficult, or abstract concepts which abound in science. This article makes two new contributions to the literature. First, it clarifies the relationship between metaphors and analogies, about which there is some confusion and disagreement in the literature. Secondly, by examining three additional linguistic problems associated with metaphors used to explain evolution by natural selection, this article expands our understanding of problems which sometimes result from the use of metaphors.

Clarification of concepts, relationships, and terminology

The analogy–metaphor relationship

Although much has been written about analogies and metaphors, and their value in science, the meanings of many of the terms used, and the relationships between the concepts, are unclear and ambiguous. For example, metaphors and analogies are often spoken of interchangeably (e.g. Glynn, 1991), but although both are used to make comparisons, usually between familiar and unfamiliar ideas, the two concepts differ. This is not always recognised by authors writing about them. Gentner (1982) raises the question of whether all analogies are in fact metaphors. Other authors express different opinions: for example, Rundgren et al. (2009) use metaphors as the umbrella term to include analogies, metaphors and similes. Duit (1991) sees analogies and metaphors as situated at two ends of a spectrum differing in the degree of explanation provided. The terminology problem is not just a matter of lack of clarity. The nature of metaphors is hotly contested in the literature, making the problem a conceptual one too (Pramling, 2009).

A pragmatic approach can be used to solve these problems from a linguistic perspective, using dictionary definitions of the terms followed by the use of logic to clarify the relationships. This approach suggests that analogy is the superordinate concept (see Figure 1). An analogy is an “agreement or similarity, esp (sic) in a certain limited number of features or details”, and “a comparison made to show such a similarity” (Collins Dictionary, 2009), “for the purpose of explanation or clarification” (Analogy, 2010).

Analogies introduce a new and unfamiliar concept to be learned by relating it to a different concept more familiar to the learner. Basing new knowledge on existing ideas explains why educators who subscribe to the constructivist notions of learning, epitomised in the work of Piaget, Ausubel, and Vygotsky, support the use of analogies. Ausubel emphasises the importance of starting teaching and learning by establishing students’ existing ideas and moving on from there, and analogies are intended to do this.

Confusingly, different terms have been used by various authors since Richards coined the original terms in the 1930s (Richards, 1936) to describe the two different domains being compared in analogies (see Table 1). I will use source to describe the familiar idea, being the term requiring the least cognitive interpretion, and hence the easiest to use; target (the most common and meaningful term) to describe the new concept being introduced; mapping to describe the process during which similarities and differences between the source and the target are explained to the message recipients; and grounds to describe the reasons given when explaining the analogy.

Table 1. The variety of terms used in the literature about analogies

Vygotsky emphasises the importance of tools in the learning process, and two linguistic tools frequently used in analogies are metaphors and similes. A metaphor is a “figure of speech in which a word or phrase is applied to an object or action that it does not literally denote, in order to imply a resemblance” (Collins Dictionary, 2009). The comparison of similarities means metaphors are a type of analogy (making metaphors a subordinate concept, as shown in Figure 1). It is important to note the “word or phrase” in the definition. Goatly (2011) makes the point that metaphors may develop over time, and active metaphors which started life as linguistic non-literal phrases can become “tired”, “sleepy”, “dead”, and eventually “buried” as their meanings change, often becoming more literal so the linguistic origins are forgotten and the metaphor “dies”. These short linguistic phrases can be explained further by the person communicating the message, for example, Al-Zahrani (2008) refers to linguistic metaphorical phrases as metaphorical expressions which, once elaborated (in the form of analogies), become conceptual metaphors. I will refer to the latter as extended metaphors, because communicators inevitably have to expand on the original metaphor in order for it to be understood. Metaphors are therefore cognitive devices as well as linguistic ones (Indurkhya, 1992).

A comparative figure of speech spoken of less often in the literature is the educationally undervalued simile, “a figure of speech that expresses the resemblance of one thing to another of a different category, usually introduced by as or like” (Collins Dictionary, 2009). An important additional point about similes as linguistic tools is that they are often “used to make a description more emphatic or vivid” (Simile, 2014), which gives them motivational benefits.

Analogies are therefore cognitive devices often used to aid comprehension by comparing objects or events which have similarities (and some differences). They can make use of linguistic figures of speech such as similes (explicit comparisons often using the terms “like” or “as”) and metaphors (in which the concept to be explained—the target—is described literally as being the second non-literal more familiar concept—the source). If we see analogies as the umbrella term and similes and metaphors as subordinate concepts, as shown in Figure 1, it becomes apparent (according to the conventions of classification) that while characteristics of analogies will also apply to the subordinate concepts, the reverse will not always hold true. Thus although much of the pedagogical advice in the literature refers to analogies it is also relevant to the subcategory of metaphors. However, some of the disadvantages of metaphors will not automatically hold for all analogies. Furthermore (see Figure 2 for terms) we need to distinguish between metaphors which are literary expressions involving a word or short phrase for the sake of brevity (metaphorical expressions) and enriched metaphors, where the author goes on to explain the analogy behind their literary term, which essentially means the metaphorical message no longer fulfils the criteria for a metaphor (usually just a word or phrase), and becomes an analogy.

Two further terms relevant to this article, but used inconsistently in the literature (Duit, 1991), require clarification, model and schema. Because models involve mapping, Duit (1991) considers that they provide analogies, and that it is incorporating an analogy that makes a model a model, which may be why the two terms (analogy and model) are sometimes used interchangeably. The implication is that scientists are the generators of models (Duit, 1991). However, many authors use the term model to refer to the mental picture being constructed by students as they learn about a new concept. I suggest distinguishing between the mental generation of the ideas of these two groups of people (scientists and students) by referring to the mental constructs of scientists as models (thus models we should aim for) and those of learners by the term schemata. This term is commonly used by educational theorists, referring to mental constructs which develop as people assimilate and accommodate new concepts into pre-existing mental frameworks (schemata). The different use of these terms is illustrated in Figure 2.

The generator—message—recipient terminology

Al-Zahrani (2008), using a cognitive-linguistic theory of metaphors, implies that interactions between metaphors (referred to as “metaphorical expressions”) and the “conceptual metaphors” that they represent move in different directions depending on who is involved, and the purpose of their thinking. In Figure 2 I build on this notion, showing the hypothesised situation for the metaphor generator (the scientist who conceived the idea, shown on the left in Figure 2) and recipient of the metaphorical message (other scientists, teachers, or students, shown on the right in the diagram), and the language of the message itself (shown in the centre). Although students can generate analogies and metaphors, I have not addressed that matter in this article. Scientists (the metaphor generators) build what Boyd (1979) calls theory-constitutive metaphors as they engage with new ideas and try to express them in a way which is comprehensible to their peers. They often use analogies and metaphors to do so, as well exemplified by Glynn (1991). This is done in order to move from familiar concepts to the new original idea being proposed. As shown on the left of Figure 2, scientists start with their pre-conceptual models, moving through a series of intermediate models as they conceptualise their as yet speculative ideas and develop and focus their thinking, often arriving finally at a succinct term which is a metaphorical expression summarising the whole concept. The mental frameworks they develop as they proceed are referred to as intermediate models, and once the scientific concept has been widely accepted by the scientific community the description can be taken as the correct scientific model which teachers try to help students to understand. The message they produce therefore moves from a conceptual metaphor fully explained in the scientist’s description, and ends with the summarising linguistic metaphorical expression (as shown in the central column of Figure 2). The recipient (who could be a science peer at this point, or the public, including teachers and students learning about the scientific concept) usually encounters the metaphorical expression first and then, as the metaphor is extended in the message, will get to grips with the conceptual metaphor. Recipients will have one or more pre-existing mental frameworks (schemata) based on their life experiences, but as they go through the learning experience they will modify their schemata by assimilating and accommodating new ideas, probably passing through several intermediate schemata before reaching the final one they have developed by the end of the learning experience.

The place of alterity in the pedagogical success of analogical messages

Many of the initial claims about the pedagogical value of analogies (including metaphors) were little more than predictions based on theoretical assumptions about using the familiar to explain the unfamiliar. The empirical evidence has proved ambiguous (Duit, 1991), showing levels of understanding are not always as high as expected and that alternative unscientific conceptions may develop (Harrison & Treagust, 2006). The contradiction between benefits and drawbacks of analogies has been described in the literature using different metaphors, including a “double-edged sword” (Glynn et al., 1989), giving birth “to as many monsters as healthy babies” (Bunge 1973, cited by Duit 1991), and analogies as “friend or foe” (Harrison & Treagust, 2006) which “can shed light or cast shadows” (Carpenter, 2008).

As pointed out by Cameron (2002), if we can understand how metaphors work, and what obstacles they may cause, we will be in a better position to deal with them. In trying to understand why some analogies promote and others hinder the understanding of science concepts it is useful to remember that different types of analogies and metaphors exist, each associated with different levels of alterity (Cameron, 2002; 2003). Alterity is associated with differences of meaning constructed by different groups of people, in this case the communicator and the recipient of the analogy message. Essentially, alterity refers to the gap in the understanding of the message by the two groups. However, alterity can change, depending on how the analogy is presented. Cameron (2003) suggests that the level of alterity decreases as additional explanations are provided (towards the right in Figure 3). Harrison and Treagust (2006) describe three types of analogies identified by Curtis and Reigeluth (1984), based on the level of clarification provided by the communicator. The first type is simple analogies, which are short comparative claims without an explanation of the reasons (grounds) for the analogy, so interpretation is left up to the recipient. Because they are not explained they may be poorly understood and are susceptible to misinterpretation. “Metaphorical expressions” belong to this category because the terms are not explained. The second type is enriched analogies, where the grounds for the analogy are explained. Extended analogies provide the third type, where similarities and differences are mapped out for the message recipients, which Harrison and Treagust found resulted in fewer alternative conceptions.

The sub-types of analogies are shown below the alterity continuum in Figure 3. Metonymy has the highest level of alterity. Metonymy is “a figure of speech consisting of the use of the name of one thing for that of another … with which it is associated” (Metonymy, n.d.), for example “Wall Street” being used to refer to the financial district in New York, and “nature” as a force capable of selecting well adapted organisms for survival in the case of natural selection. Such terms are difficult to understand unless their meaning is already known to the message recipient. Metaphorical expressions (e.g. “natural selection’) also have a high level of alterity, especially when the target is unknown and the source open to misinterpretation. However, the terms themselves do have some logical meaning. Similes, as a type of analogy, are slightly less difficult to understand because although brief they do include terms such as “like” or “kind of” (referred to by Cameron, 2003, as tuning markers) which, unlike metaphorical expressions, give an indication that a comparison is being made. Enriched metaphors, are examples of enriched analogies, so the grounds for the comparison are provided, which lowers the level of alterity. Finally, extended metaphors, as specific cases of extended analogies, are extensively mapped for the message recipients, so have the lowest levels of alterity, and are the most likely to be understood and the least likely to generate alternative conceptions. This figure suggests why the claim that the difference between analogies and metaphors is that the former are explicit and the latter implicit (Duit, 1991) is inaccurate.

Many authors echo Gentner (1982), who claims that the specificity with which the mapping is clarified in the analogy, and the clarity of the explanation, are crucial for good science analogies. Extensive mapping is recommended by numerous authors as a way of using analogies more effectively, for example, in the Teaching-with-analogies (TWA) guidelines (Glynn, 1991) and the Focus—Action—Reflection (FAR) guidelines (Harrison & Treagust, 2006). Cameron (2002, 2003), dealing specifically with metaphors, supplies eight pieces of advice based on her research, including the use of a number of mediational devices which provide metacognitive opportunities to improve pedagogical effectiveness of metaphors by reducing alterity. These include tuning, which alerts the recipients of the metaphor to the fact it is not literal and should be interpreted with care.

Challenges identified in the metaphors research

Different people in the sciences use metaphors for different purposes

As noted by numerous authors writing about analogies and metaphors in science (e.g. Boyd, 1979; Glynn, 1991; Cameron, 2003; Pramling, 2009) two different groups of people use metaphors, and use them for different purposes. Harrison and Treagust (2006) suggest scientists use metaphors both as a thinking tool and as a mechanism to explain new scientific ideas to their peers in a way that will be comprehensible and convincing. Starting from a familiar framework of scientific facts and moving from there to the new idea is a commonly used strategy amongst scientists. They frequently develop a short succinct phrase that will summarise their idea, and often such phrases are metaphorical because they make comparisons which appear on the surface to be incongruous. The second group of people encountering metaphors is those receiving the metaphorical communication. This group is varied, and includes other scientists, as well as lay people (members of the public, teachers, textbook writers, and students of all ages). What they have in common is they are learning about the new idea being presented and, as the research has shown, when metaphors are used they are open to misinterpretation. This has happened in all the recipients mentioned above including the peer scientists, as illustrated by Darwin’s experiences, discussed later.

Anthropomorphism and teleology cause additional linguistic problems in communication messages

Two types of thinking considered unacceptable in science—teleology and anthropomorphism—provide additional obstacles when interpreting metaphors. Teleology involves “the doctrine of design and purpose in the material world”, explaining “phenomena by the purpose they serve rather than by their … causes” (Concise Oxford Dictionary, 2006) Teleological thinking is used to explain why things exist (Keleman, 1999), but has long been considered an “invalid principle” in science (Mayr, 2004, 23). Mayr explains a teleological worldview as leading to a definite goal, implying purpose, intention, and goal-directed behaviour, a viewpoint rejected by scientists (Ayala, 1970). Teleological thinking is “a primary component of human cognition” (Kelemen, 1999, 463) especially in young children, who tend to view all structures (living and non-living) as “for something”. Even adults may think teleologically, although they tend to limit teleological thinking to living organisms (Kelemen, 1999). Jungwirth (1977) points out that the problem is that people often take teleological statements literally and not metaphorically as intended, only the latter explanations being acceptable in biology. However, Tamir (1985) and Mayr (2004) point out that teleological thinking has been used generatively by scientists so does have value, stimulating investigations into why certain structures exist, and leading to valuable new discoveries. The problem is that when students interpret such teleological statements as causal this results in misconceptions (Tamir, 1985; Beggrow & Nehm, 2012).

Anthropomorphism is defined as “the attribution of human characteristics or behaviour to a god, animal or object” (Concise Oxford Dictionary, 2006). Several authors writing about metaphors address the issue of anthropomorphism without using the term. Lakoff and Johnson (1980) and Cameron (2003) use the term personification when the agent in the metaphor is given human-like features. As explained later, anthropomorphism and teleology probably result in alternative conceptions about evolution by natural selection, commonly noted in the science education literature (e.g. Galli & Meinardi, 2011; Beggrow & Nehm, 2012).

Pramling (2009) points out that analogies spoken of in anthropomorphic and teleological terms are metaphorical because they are not literally true. I have therefore added anthropomorphism and teleology to my list of linguistic threats resulting from the use of metaphors. Because multiple threats exist, not just two, I use the term “razor-wire” metaphors to expand the “double-edged sword” analogy of Glynn et al. (1989), although their metaphor refers to the consequences of metaphors (the benefits and risks) while mine refers to linguistic expressions as potential causes of problems. Although the multiple blades used in razor-wire security fences are intended as a deterrent for intruders, they unfortunately also trap the unwary. The latter is true for the multiple linguistic threats associated with metaphors used in science education.

Paradoxical jargon terms add to the confusion

The final linguistic blade in my razor-wire metaphor is the threat associated with the use of paradoxical jargon words in science, words which have more than one meaning (Ryan, 1985). When the everyday meaning of a word is different to the meaning of that word when used in a science context alternative conceptions can result if the terms are not carefully taught. For example, the term “animal” is often considered in everyday English to be a four-legged, furry, terrestrial mammal (e.g. as in the sign “no animals allowed in the shop’). However, scientists interpret the term to include all animals (including invertebrates, lower vertebrates like fish, and humans). Interpreted scientifically, the shop sign would exclude humans from entering the shop.

The term paradoxical jargon is not used in the metaphors literature, although the concept is raised (e.g. Glynn et al., 1989; Goatly 2011). Glynn and his co-authors point out that one factor making science difficult to comprehend is the existence of such dual meaning. It is more interesting to note that Goatly (2011, pp. 29–32), in his list of active, tired, sleeping, dead, and buried metaphors, includes many examples of paradoxical jargon words to explain that often these expressions started as non-literal metaphorical expressions and then became literal (resulting in dead metaphors).

Application of metaphor theory to the concept of evolution

What evolutionary theory says

To identify alternative conceptions, people’s ideas need to be compared with current scientific models. The scientific model for modern evolutionary theory, known as “the evolutionary synthesis”, represents scientific consensus on the “facts” of evolution as they have been added to in the 150 years since Darwin published his initial ideas on evolution by natural selection. They have been summarised by the evolutionary biologist Futuyma (2009) as a list of just 16 points. However, the gist of the theory suitable for students is contained in just six statements. 1) Individual organisms in a population (all individuals of a species living in a particular area) show phenotypic variations based on slight differences in their genotypes. 2) Some of the variations confer survival advantages on the individual in its particular niche. 3) Individuals with these traits are reproductively more successful than those without the traits. 4) Because of their reproductive success the favourable alleles pass to more offspring in the next generation than would less-favourable alleles. 5) The advantageous trait therefore becomes more common in the population of organisms over time (i.e. the allele becomes more frequent in the gene pool). 6) After many generations the populations will have changed notably, i.e. will have evolved. Evolutionary changes in a population are often referred to as adaptations, but adaptations are no more than evolutionary developments over many generations. Individual organisms cannot adapt as they cannot change their genetic make-up.

Alternative conceptions and alternative frameworks about evolution by natural selection

Unscientific ideas have commonly been referred to as alternative conceptions. These are single concepts which do not concur with the current ideas of scientists. However, these single ideas are often influenced by a whole mental schema which is not aligned with scientific views. Such broad ways of thinking unscientifically are referred to as alternative frameworks (Driver & Erikson, 1983), and each framework is linked to many individual alternative conceptions about a particular science topic.

Two such alternative frameworks are associated with evolution by natural selection, and each is linked to several common individual alternative conceptions. The first of these is aptly named “evolution on demand” (Jensen & Finley, 1995, 156). This misleading alternative framework about adaptation is associated with at least six individual alternative conceptions—that a) individual organisms adapt, b) usually in response to changing environmental conditions or food sources, c) by intentionally initiating changes d) because they “need” to do so in order to survive [the “adapt or die” mentality]; e) they do this within their lifetimes, and f) these acquired adaptations will be passed on to their offspring.

The second alternative framework is associated with two metaphorical clichés survival of the fittest and adapt or die (van Dijk & Reydon, 2010). Unscientific (alternative) conceptions associated with this framework include that a) only the fittest, or only those with favourable adaptations, survive; b) the opposite idea that organisms which are less favourably endowed will die or become extinct; c) only the favourably endowed will reproduce; d) the opposite idea that the less favourably endowed cannot / will not reproduce; e) all offspring of the favourably endowed individuals will inherit the favourable traits; and f) the whole population will eventually be made up of only favourably endowed individuals.

Darwin’s use of metaphors

Darwin used metaphors extensively in the six editions of his book on the origin of species, published between 1859 and 1872. Although he had worked on the book for 20 years, he had been very reluctant to publish his ideas because he was aware of the religious furore that was likely to erupt (he wrote to a friend “it is like confessing a murder” (Young, 1985, p. 88)). At the insistence of some of Darwin’s peers who knew about his ideas, his work was forced into the open in a paper written in 1858 with a co-author, Alfred Wallace, whose parallel but more recent work was about to be published.

Darwin has since been recognised as both one of the most influential scientists ever and as a master of the use of metaphors (Brooks, 2011). Brooks (2011, p. 446) explains that scientists generally “mistrust metaphors because they allow too many possibilities, thus introducing ambiguity”. He points out, however, that when scientists are unsure, introducing new ideas, or trying to change old ones, they tend to use metaphors. Brooks states that because metaphors allow comparisons to familiar or old ideas they aid understanding, explaining that Darwin’s metaphors gave him (Brooks) new insights into aspects of natural selection. Brooks also claims metaphors are the means for allowing non-scientists to understand science concepts. He suggests that Darwin was skilled in linguistics and his ability to link the everyday to the ideas of scientists was the reason his work was so well understood by non-scientists.

Darwin’s writings, particularly his metaphors, have been extensively analysed from two different sources: the books themselves (e.g. Pramling, 2009) and Darwin’s correspondence with his peers as the comments on his book appeared (e.g. Young, 1985; Campbell, 1989; Munöz-Rubio, 2003; Al-Zahrani, 2008). Darwin spent 20 years in the theory-constitutive stage (Boyd, 1979), but analyses show that Darwin was very conscious that he was using metaphors in his writing, and was doing this with two intentions other than theory building. Firstly, he was using extended conceptual metaphors which helped him to argue from the familiar to the unfamiliar, to convince his peers, who he knew would be skeptical because of their religious views. Extracts cited by Al-Zahrani (2008) show how successful this strategy was in producing an argument easy for even a layperson to understand.

Secondly, Darwin agonised about the metaphorical expression to use as a succinct phrase to encapsulate his idea. Darwin’s notion of natural selection was based on an analogy with the idea of artificial selection, in which humans have purposefully used selective breeding to ensure that only plants or animals with desirable traits reproduce, so that over generations new strains are generated with the desired trait emphasised. For him the term “natural selection” was an obvious follow-on from the “artificial selection” analogy. However, when critics (many friendly to Darwin) responded to the first edition of his book, their objections related almost wholly to the teleological and anthropomorphic inferences of this term (Young, 1985; Munöz-Rubio, 2003; Al-Zahrani, 2008). In a letter to Darwin, Wallace wrote: “I think this arises almost entirely from your choice of the term “Natural Selection” and so constantly comparing it in its effects to Man’s Selection, and also your so frequently personifying nature as “selecting” … it is evidently also necessary not to personify nature too much – since people will not understand that all such phrases are metaphors” (Young, 1985, 100).

But having decided on “natural selection” Darwin strongly resisted efforts from his peers to change the term. He recognised the problem, but felt both that the term was by that time too well known to change, and that people had grown to understand it was a metaphor. He did, however, add the metaphor “struggle for survival” (which itself caused problems—see Young, 1985; Todes, 1989) in later editions of the book. Darwin countered, both in letters to his peers and in the rewording of his third edition of the book, admitting to the problem created by his metaphor “natural selection’, but justifying the need for brevity in his expression, and arguing that other scientists used similar metaphoric devices (which are anthropomorphic and teleological). He added to the third edition of his book:

In the literal sense of the word, no doubt natural selection is a false term … It has been said that I speak of natural selection as an active power or Deity; but who objects to an author speaking of the attraction of gravity as ruling the attraction of the planets? Everyone knows what is meant and is implied by such metaphorical expressions: and they are almost necessary for brevity. So again it is difficult to avoid personifying the word Nature (Al-Zahrani, 2008, 55).

One value of metaphors Darwin may not have been aware of is that scientists tend to use them when they are still feeling their way through new ideas, and lack certainty. The ambiguity of metaphors becomes an advantage (Young, 1985). Although Darwin suggested natural selection as a mechanism for evolution, he had no idea how the natural selection actually happened (Mendel’s work on genetics was not yet known). Darwin’s metaphors allowed his “theory” to remain vague. He did, however, acknowledge the creative aspect of the analogy, because his knowledge of artificial selection led him to think about natural selection (Young, 1985). Darwin wrote: “I have read heaps of agricultural and horticultural books, and have never ceased collecting facts” (Young, 1985, 88).

Possible links between alternative conceptions about evolution and linguistic “risk-terms’

An important message for educational stakeholders is that the linguistic devices presented in the razor-wire analogy in this article are considered “risk-terms’(Tshuma & Sanders, 2014) for teaching evolution. Analyses of South African textbooks (Tshuma & Sanders, 2014; Sanders, 2014) have shown the use of many such risk-terms: euphemisms, metaphors, paradoxical jargon, anthropomorphism, and teleology.

•Metaphors: Tshuma and Sanders (2014) list metaphors as risk-terms. The risks they pose are described in this article, so will not be discussed further here.

•Anthropomorphic and teleological statements were found to be frequent (n=60 and n=115 respectively) in a study involving analysis of 11 junior natural sciences textbooks in South Africa (Sanders, 2014). Humanising other organisms (anthropomorphism) suggests that they are forward-looking beings, able to predict their future, and capable of altering their destiny should environmental circumstances demand it. The scientific model provided earlier shows this is not the case. Attributing adaptations to environmental causes (teleology) is a common alternative conception. Mayr (2004, p. 43) argues that “final causes … are far more plausible and pleasing to the layperson than the seemingly haphazard and opportunistic process of natural selection”, but points out that no “teleological processes work backward from an unknown future goal; there is no backward causation” (Mayr, 2004, 61). He explains that teleology was a prevalent way of thinking amongst biologists until Darwin provided natural selection as a way of answering “why” questions in biology—i.e. providing a causal explanation for the structural and behavioural adaptations of living things, not based on individual choices and actions.

•Paradoxical jargon terms abound in evolutionary theory (selection pressure, theory, adapt, fitness, survival) and can be linked to common alternative conceptions. For example, a theory in everyday English refers to a speculation or guess, while in science an idea only reaches theory status if it can explain many observations, and has been rigorously and repeatedly tested, providing evidence so convincing that the idea is widely accepted by scientists. However, a common alternative conception (that evolution is only a theory not yet proven, so one does not have to be concerned about it) is the result of using the everyday English meaning of the term. Selection pressure has a meaning in biology not linked to the everyday meaning of pressure (as in peer pressure) which leads many to believe erroneously that there is a force causing evolution to happen (Nehm, Rector, & Ha, 2010).

Many paradoxical jargon terms occur in metaphors. Survival of the fittest is a metaphor not literally true, and contains two paradoxical jargon words: “Survival” in the metaphor does not refer to individuals living or dying but to the long term well-being of populations, so it is possible for “less fit” organisms to survive and even reproduce. And “fitness” does not have the everyday meaning of physical health and well-being, but refers to increased levels of reproductive success (Futuyma, 2009). The metaphor adapt or die also contains two problematic paradoxical jargon terms. Not all organisms which lack an adaptation will “die” (Brooks, 2011) although this is a common alternative conception. Adaptation in everyday English refers to an ability to change one’s behaviour to suit changes in external conditions or situations. In biology, however, it refers to evolutionary change, which has to involve genetic changes in a population. The word causes serious problems for students, even though good quality English dictionaries point out the two different meanings. An additional problem is that “adapt” is a euphemism (see next point).

•Euphemisms are terms used to replace others which could cause offense. Adapt, change, acquire, become, and develop are euphemisms for evolve. Thompson (2008) points out the problem with using “adapt” instead of “evolve” is that scholars learning about adaptation may not realise they are actually learning about evolution. Tshuma and Sanders (2014) found 56 instances, in six textbooks analysed, where “adapt” or “adaptations” were used when “evolved” or “evolutionary adaptations” would have been more appropriate. Used without explanation euphemisms are likely to lead to misconceptions.

•Metonymy: Darwin’s metaphor “natural selection” uses metonymy, involving “nature” as an abbreviated representative entity controlling the biological genetic processes occuring in populations of organisms during evolution. There is no such thing as nature capable of selecting (Young, 1985).

These risk-terms, together with most of the alternative conceptions identified earlier in this article in the two alternative frameworks presented, occur in six Grade 10–12 life sciences textbooks analysed (Tshuma & Sanders, 2014). The most frequent unscientific ideas included several from the “evolution on demand” framework: individual organisms evolve (n=15), environmental changes cause evolution (n=10), individuals evolving in their life times (n=5), in order to survive (n=4). Unscientific ideas were also associated with the second alternative framework, “survival of the fittest” and “adapt or die’: less fit organisms die (n=6), the fittest survive (n=5), favourable characteristics WILL be inherited by the offspring (n=5), and several others (found less frequently). Research in South Africa, and elsewhere in the world, shows such alternative conceptions to be common amongst teachers, so it is not surprising that because errors and risk-terms in textbooks are often not recognised by teachers, many students have alternative conceptions.

Concluding remarks

Several problematic terms about which there is confusion in the literature have been examined to find suitable explanations for them, and to establish hierarchical and temporal relationships between them. One of the issues has been a lack of recognition by many authors that metaphors do not all fit a standard definition: there are different types, and they change with time. Furthermore, it has become apparent that metaphors are just one thread in a web of related linguistic problems. Few science education researchers seem to have considered these threats in a formal holistic way which clarifies both the threats and the relationships between them. Using aspects of linguistic theory to understand the problems raised by metaphors when learning about evolution by natural selection has pinpointed that the problem is more than just one of metaphors being difficult for some people to interpret, or that metaphors can cause alternative conceptions. There is good reason to believe that numerous problems together form a mutiple threat for which the term “razor-wire metaphors” seems an appropriate descriptor. For example, the link between common alternative conceptions and the anthropomorphic and teleological statements made in communications about adaptations (written or verbal) suggests that it would not be sound educational practice to lift the taboo on anthropomorphism and teleology (see Zohar & Ginnosar, 1998). And teachers who are more aware that risk-terms might cause misunderstandings would be in a better position to avoid them or to make the threats more overt so students could avoid harbouring or developing alternative conceptions.

Several of the implications for improving teaching when using metaphors (which are a particular type of analogy) have not been covered in this article, and there are gaps in the theoretical framework which still need to be filled. One of these is a more systematic holistic summarising of advice from the literature, which could not be dealt with here for lack of space. For example, understanding meanings depends on the interpretative frameworks available to individuals, as well as assistance given by teachers (Harrison & Treagust 2006). Goatly (2011) suggests it is not only background knowledge which is important. He looks at the impact of relevance theory and the need for the knowledge constructor to have knowledge of the language and the context in which metaphors are used. More information is needed on the strategies recommended by various authors wanting to improve the effectiveness of using analogies, particularly metaphors. For example, the strategies suggested by Cameron (2003) to reduce alterity need to be woven into part of a single set of guidelines together with what other authors have suggested. Having a better theoretical framework will benefit researchers wanting to investigate the topic further, and teachers wanting to address the prevalent problems of alternative conceptions.

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The author

Professor Martie Sanders is a teacher-educator in Animal, Plant and Environmental Sciences at the University of the Witwatersrand, Johannesburg, South Africa. Her research, and that of her postgraduate students, has focused on aspects of teaching evolution when this topic is added to a school curriculum. The research has been conducted in South Africa and England.

Email: Martie.Sanders@wits.ac.za