Analysing bio-art’s epistemic landscape: from metaphoric to post-metaphoric structure

Since its emergence, bio-art has developed numerous metaphors central to the transfer of concepts of modern biology, genetics, and genomics to the public domain that reveal several cultural, ethical, and social variations in their related themes. This article assumes that a general typology of metaphors developed by practices related to bio-art can be categorised into two categories: pictorial and operational metaphors. Through these, information regarding several biological issues is transferred to the public arena. Based on the analysis, this article attempts to answer the following questions: How does bio-art develop metaphors to advance epistemic and discursive agendas that constitute public understanding of a set of deeply problematic assumptions regarding how today’s biology operates? Under the influence of today’s synthetic biology, could bio-media operationally reframe these epistemic agendas by reframing complex and multi-layered metaphors towards post-metaphoric structures? Finally, what are the scientific, cultural, and social implications of reframing?


Introduction
Since Alexander Fleming discovered penicillin on bacterial paintings in 1929, which he made on paper and Petri dishes between his experiments, a form of hybrid artistic-scientific practices began to emerge involving the use of biomaterials (Caputo 2016). Several scientific techniques and protocols have been adapted to develop biological investigations in new media arts. 1 These can employ diverse levels of biological manipulations ranging from the whole organism to the cell and molecular levels, and apply a wide range of bio-technologies from physical manipulation to tissue culture and further to genetic engineering (Yetisen et al. 2015). To discipline this new path of practices, bio-artist Eduardo Kac coined the term bio-art in 1997 with reference to his artwork "Time Capsule". This umbrella term refers to artworks that use life and life manipulation as an expressive medium while engaging with direct practices of biology and life sciences (Kac 1997).
Since its emergence, bio-art has widely supported an intensified set of conceptual metaphors. Here, communicating modern biological disciplines to the public would be impossible without metaphors such as "information", "code", "letter", and "language" (Stelmach and Nerlich 2015). On one hand, such metaphors frame artists' viewpoints on several critical and complicated issues regarding today's biology. On the other, they deeply affect artists' adopted ways and strategies to transfer biological information to the public and therefore, contribute to constituting public understanding of several problematic issues regarding how biology operates today (Nelkin 2001). These metaphors are built in a conceptual structure that can be reflected linguistically, gesturally, or visually by connecting different orders of reality to enable the translation of complex scientific information in culturally meaningful ways (Lakoff 2014).
Therefore, this article differentiates between two major structural models used in practices related to bio-art to rebuild conceptual metaphors in the context of the artworks. The first is metaphors based on a pictorial model, through which many artists understand bio-artworks as conceptual artworks that raise critical debates regarding today's biology and biotechnology. The second is metaphors based on an operational model, through which artists use real biological tools and processes 2 to investigate related issues in the context of their own viewpoint.
The mutual continuous interplay between these two structural models of metaphors (pictorial and operational) usually refers to the conflicting classification of bio-art related practices caused by their fuzzy borders. Therefore, considerable uncertainty exists about what medium or form these practices should employ. A lot of practitioners often employ the term bio-art indiscriminately. On one hand, artists 1 Several authors mentioned that Edward Steichen was the first artist who employed genetics as an art medium in the 1930s. Relatively early on, similar means were used by George Gessert. 2 Here, Operational metaphoric structure needs a real biological tools and processes as Kac emphasized in his manifesto when he talked about direct biological intervention as a necessity to count an artwork as a bio artwork. However, some bio artworks use real biological tools and processes but with non-living or semi-living material and these are also considered bio artworks as their real biological processes run to investigate life-related related concept.
apply it using metaphors based on the pictorial model to their paintings of robots or chromosome-shaped classical sculptures, drawings or paintings inspired by biological elements at any scale, or biological microscopic images. 3 On the other, several scientific experiments implicitly confirm that the term bio-art attributes the value of this practice to the pure biological material of bio-artworks. For instance, for Yetisen and colleagues, the term bio-art refers to the blurred boundaries between art and modern biology such that experiments could be viewed solely from a biology lens (Yetisen et al. 2015). Likewise, as the first bio-artwork at the University of Oxford's Museum of the History of Science, Anna Dumitriu described his artistic experiment depending on its material and manipulation processes (Swain 2018). Furthermore, the Federation of American Society for Experimental Biology runs an annual contest for biology specialists to select the best scientific images in biomedical sciences research, calling the selected images bio-artworks (FASEB 2021).
However, although the term bio-art was coined to distinguish artworks made of biological material, this does not conflict with the fact that this practice is rooted in new media arts. Therefore, the usual processing of the biological material itself inside the lab is purely science and has nothing to do with bio-art unless new media artists or scientists design a custom-made process to re-manipulate this material within the conceptual framework of the operational structure system of the artwork. Hence, the resulting artwork would produce an ephemeral process-based expressive metaphor in vivo or in vitro, allowing the audience to partake in it emotionally and cognitively 4 (Hauser 2006).
This misleading categorisation of a plethora of works led Kac and six bio-artist colleagues to raise a second version of the first manifesto in 2017 to determine well-defined boundaries of bio-artworks. They listed ten conditions to categorise any artwork as a bio-artwork. An important point in this manifesto is that "without direct biological intervention, 5 the art made solely of acrylics, paper, pixels, plastic, steel, or any other kind of non-living matter is not Bio Art" (Kac 2017). Here, Kac contends that artists who "conceptually engage biotechnology as a pictorial topic" must be distinguished from those who "engage with biotechnology operationally on a material/processes level". Emphasised is the crucial difference between drawing or picking a picture of a cell, for instance, and using the real cell as a real biological system that operationally co-governs the rules of the physical environment of the artwork's system. Based on this viewpoint, Adam Zaretsky coined the term "Vivoarts", which he defined as any artistic production with a living component embedded in it at the time of its exhibition. Through this, Zaretsky clarifies what Kac means by direct biological intervention and how it may help sort the aesthetic and social concerns when considering the question of real life in art (Zaretsky 2017). Accordingly, all artworks carried out to discuss biological concepts using metaphors based on the pictorial model are not the artworks the term bio-art originally intended.
However, to reconcile various definitions, several commentators attempted to redefine practices related to bio-art. These attempts can be categorised into two camps. The first opposes Kac's manifesto, arguing that bio-artworks could be unified by their shared interest in conceptually generating 'critical debate' about today's biology. In this case, it does not matter whether an artwork employs paint, sculpture, or muscle cells as its medium. The second supports Kac's vision, arguing that the members of a privileged subset of these works must be unified by their media so that biological intervention is inevitable (Radomska 2016). For instance, when she talked about the epistemic practices in bio-art, Suzanne Anker supported the first camps as she claimed that several sub-genres of bio-art could include all traditional media, including painting, sculpture, printmaking, and drawing to convey novel ways of reflecting on life forms and their attendant implications (Anker 2021). Perhaps her claim could be reasonable when talking about these traditional genres of practices purely artistically. However, in terms of the capabilities of the produced epistemic frames, ignoring the operational and functional differences between the metaphoric structures used in these traditional genres of practices and those metaphoric structures used in the genres that involve real biological interventions is quite enough to dispute this claim. In this regard, Robert Mitchell operationally and functionally differentiates the methodologies of the epistemic practices in these two camps of practices related to bio-art as "presenting processes" and "re-presenting processes". He described the former under the vitalist tactic, which reflects on using biotechnology techniques, is processed with laboratory techniques, and uses living material. He described the latter as a prophylactic tactic that includes works operated from outside the context of biotechnology and that apply traditional media or non-living material (Mitchell 2010). In other words, designing an operational metaphor by presenting processes requires a clear biological intervention. However, representing processes are not adopted only for topic-related reasons. The artist may not have the required facilities or skills to employ biotechnology techniques in his idea, or his idea is more complicated than can be achieved through today's existing technology. In all these cases, the artist may re-present his idea by designing pictorial metaphors using traditional media rather than presenting it operationally using biotechnology.
In this context, this article attempts to build an analytical framework to investigate the requirements of the successful metaphoric structures needed by genuine bio-artworks based on the operational and functional properties of the epistemic landscape of these metaphoric structures and beyond their morphological properties. It therefore reveals the extent to which some kinds of metaphoric structures belong to genuine bio-art. Accordingly, this article elucidates how bio-art develops metaphors to advance its epistemic and discursive agendas that contribute to constituting public understanding of a set of deeply problematic assumptions regarding the consequences of today's biology operations. Influenced by today's synthetic biology and the technologies beyond, could bio-media reframe these epistemic agendas by re-constructing complex and multi-layered metaphors towards post-metaphoric applicable examples? In turn, could this analysis framework guide the audience to filter false convictions that may be exported to them because of the metaphoric deficit of immature metaphoric structures in this artistic practice?
The metaphoric structure according to genuine bio-art

Metaphoric practices
According to some references, the origins of metaphor can be traced to ancient Greece. However, metaphor as a technique of expression can be traced to the primitive age, where many simple visual metaphoric expressions were drawn on caves for magical purposes 6 (Ortiz 2011). Various theories have analysed metaphors from a linguistic base, such as Aristotle's comparison theory (Nunberg 1995), Martin's substitution theory (Parsons 2016), Lakof and Mark Johnson's conceptual theory (Lakoff and Johnson 1980), and Black's interaction theory (Black 1955). Similarly, in visual art history, there are numerous examples of employing metaphors as a conceptual approach that directly affects the composition of paintings and morphological properties of their elements. In fact, most non-classical practices use a wide range of metaphoric structures to correlate objects that cannot be realistically logically unified to smoothly realise the concept. However, the common factor combining these approaches is that they work mainly at the pictorial level, which deals with the metaphor as a stylistic, symbolic, or figurative approach to express a concept in an eloquent way. Here, the artist is not committed to considering the convergence of their elements at the level of real functional processes as long as he can combine them morphologically through his own artistic style. Several researchers have investigated the role and impact of visual metaphors in relation to traditional artistic practices, for instance (Meyer 2017;Smith 2016;Cupchik 2003;Proweller 1971).
However, the dramatic shift at the level of practices in new media arts exposed metaphoric structures to an inevitable fundamental redefinition at the operational and functional levels. This was because the artwork moved from traditional canvas or static statues to being presented as a real event in the physical environment. Therefore, the employed metaphoric structure must satisfy the operational concepts adopted by new media artworks, as they usually run through systems rather than virtual images. As such, they are presented by real processes, not re-presented by the final virtual result; they sustainably change rather than being static; their cognitive frames rely on sustainable mutual knowledge cycles, not simple visual information; and they are embodied in a hyper medium, not by traditional material. This imposes new criteria to build, analyse, and evaluate the metaphors used in these practices related to bio-art, which in addition to the previous new properties, are embodied in a living medium or living processes so that they have a level of ephemerality that complicates these practices.

The metaphoric structure as real processes
As a technique for understanding complicated issues, metaphor is a cognitive operating system applied linguistically or visually to present an abstract concept using figurative convergence with a concrete concept. In this way, the abstract concept, or "target domain", is understood in terms of another "source domain", which is well defined and concrete (Niebert et al. 2012). Projecting the source domain onto the target domain is called the "mapping process", which provides a basic understanding of how we got from Point A to Point B. In other words, the mapping process refers to a predetermined set of corresponding points between the source and target domains to understand the target domain in terms of the source domain. Therefore, metaphor is a systematic and/or methodological technique, often based not on similarities but on systematic correspondences. This is achieved by mapping elements from a concrete source domain onto elements of a more abstract target domain, which requires a defined correlation between the structures of both domains. The impact of this correlation can be attributed to describing the primary system in terms of a secondary system (Holmquist 2006).
In this regard, bio-art can export the overabundance of problematic and radical issues to the lay audience using a series of complicated metaphors that depend on the "invariance principle". This principle contends that in metaphorical mapping processes, all elements from the target domain can be projected onto the source domain if those elements are coherent with the target domain's operational system (Kövecses 2017). Therefore, the coherence level between the properties of the artwork system, which embodies the source domain, and the concept addressed as a target domain is a key property with a crucial role in evaluating the extent to which the metaphor fulfils its cogitative function at the operational level of any bio-artwork. Hence, the quality of the cognitive frame of the designed metaphor always relies on reducing the operational gap between the source and target domain such that if this operational gap is wider than the audience can mentally fill, the metaphor's cognitive frame is not informative enough. This leads to a so-called metaphoric deficit by which audiences are misguided. Forceville categorised the coherence level between the source and target domains by distinguishing "monomodal" and "multimodal" metaphors (Forceville 2008). He defined monomodal metaphors as those in which the source and target domains are represented or rendered within a common mode. Multimodal metaphors are those in which the source and target domains are each presented or rendered exclusively or predominantly in different modes, such as in verbal-audio-visual metaphorical expression 7 (Ortiz 2011). According to this classification, metaphors can be powerful persuasive tools, particularly for complicated issues. Metaphors grab attention and help lay audiences understand details; however, they can also be a trap, obstructing perspectives, limiting understanding of a situation, and confining choices (Lara et al. 2019). Thus, Carmen McLeod highlights the crucial role of a well-designed metaphor in understanding abstract concepts. However, she affirms that if the object of study becomes too remote from a lay audience's experience, the metaphor begins to do more harm than good (McLeod and Nerlich 2017).
Within this context and to avoid confusion between terms in the rest of the investigation, the article identifies accurate definitions of the key elements and processes of the process-based metaphoric structure in genuine bio-art. Although difficult to separate practically, they can be anatomised theoretically by briefly outlining their positions and roles as follows:

Physical composition of process-based metaphoric structure
The metaphoric structure of the entire composition of the installed artwork in its physical place, which combines: 1. The biological system: This refers to the biological medium and its related required sustaining biological processes that refer directly or indirectly to the concept needing investigation as the target domain. 2. The presenting system: This refers to the source domain, which comes in the form of the mechanisms the creator adopts to integrate the biological system and employ it in its processes. It is also responsible for the morphological properties of the final installed artwork.

Mapping process
These processes refer to the interactions between the biological system as the target domain and presenting system as the source domain to map the first into the second according to the facilitated functions of the presented system. These interactions usually outline the cognitive frame on which the entire artwork works. Mapping processes also refer to the coherence level between the source and target domains at the operational and functional levels.

Operational conditions
These are the conditions that govern the operations of the two artwork's internal systems (source and target domains) and how orderly and smoothly their interaction processes flow in favour of the concept of the artwork.

Functional conditions
These are the conditions that govern the external operations by which the artwork's system can affect and be affected by the external surrounding environment including input channels through which the artwork can receive data from the spectator directly or any sensor or other way of physical communication.

Cognitive framework
This refers to knowledge behind the installed composition. Genuine bio-art is an interdisciplinary practice, meaning that knowledge cycles are processed in the technical and conceptual context of their operational and functional processes. The cognitive framework usually contains the following two knowledge cycles that sustainably maintain each other: 1. The internal knowledge cycle refers to interactions between several fields to create the entire installed composition (biology, arts, computer programming, etc.). The physical indications of this knowledge are usually reflected in the technical skills used to unify the heterogeneous tools and technology derived from these different domains to implement the entire project as a unified system. 2. The external knowledge cycle refers to the data collected as a result of the communications between the entire installed composition and external physical environment including responses from spectators through any means of interactions, which also affect the internal system.
Several researchers investigated these two knowledge cycles in interdisciplinary new media artwork as a means of science outreach. Others claimed that the artwork could be considered a means of knowledge production rather than a pure means of entertainment (Parks and White 2021).
Therefore, in contrast with previous studies that concentrated on pictorial analysis, the current analysis framework does not focus on analysing or evaluating the artistic value of a set of practices related to bio-art. The analysis is important because it first clarifies what is meant by genuine bio-artwork according to the nature of its metaphoric structure, and second, analyses the quality of the metaphoric mechanism employed by these artworks to transfer biological concepts to the public domain. The current analysis targets these two points by investigating the operational and functional conditions of the metaphor's mapping processes, and their cognitive frame as reflected in the processes of the interactions between the target and source domains. Finally, by tracking the developments of the interactive relationships between the target and source domains, the analysis reveals how the mapping processes of biological concepts have shifted from the metaphoric to postmetaphoric phase, where the conceptual metaphoric structure has a level of reality.

Metaphoric structures developed through practices related to bio-art
A cornucopia of metaphors developed through practices related to bio-art is central to transferring the concepts of modern biology, genetics, and genomics to the public domain and revealing cultural, ethical, and social variations in their related themes (Stelmach and Nerlich 2015). Thus, based on the preceding analysis of metaphoric structure, a general typology of metaphors developed to analyse the quality thereof based on their abilities to fulfil their cognitive frames operationally and functionally reveals the extent to which some of these metaphors belong to genuine bio-art. A set of trajectories of practices related to bio-art were categorised into the two paths discussed below.

Pictorial metaphor-based practices
These practices are mostly monomodal metaphors. They rely on re-presenting abstract concepts of biological issues by mapping them onto a pictorial composition that reflects a concrete concept. Here, an unreal medium such as non-biological or non-living material/processes is used to process the metaphor's cognitive operating system at the pictorial level. Although most commentators refuse to consider this practice bio-art, it has affected public understanding of several problematic issues in today's biotechnology because of operational conflicts between the source and target domains during mapping processes. Of the various approaches, the following are the two most important:

Re-presenting a biological concept by mapping it onto a pictorial scene
An iconic example of this practice is the painting "The Farm" by Alexis Rockman (Fig. 1A). By depicting how biotechnology could affect natural elements, Rockman pictorially created a metaphorical comparison between a set of natural elements and the same set influenced by genetic modification (Kevles and Nissenson 2000). Although Rockman re-presented how genetically modified organisms might appear, the lay audience could be led to a series of false conventions regarding the related and (in)accurate consequences of biotechnology. Here, the source domain is the sensory motor, and the target domain is not. On one hand, the assumed pictorial phenotype of the painted organisms is an operational obstacle in the projecting process because it cannot be seriously considered the result of a real genetic modification (Potter 2009). On the other, we cannot limit the positive or negative consequences of biotechnology to morphological changes, because it aims to enhance an organism's functions. Thus, the intended meaning must employ a medium that extends its abilities beyond the limitations of the employed material, which cannot present that meaning accurately. This operational conflict between the artist's intended meaning and the medium embodying it refers to a clear metaphoric deficit that usually underlies operational problems in using pictorial metaphors that a lay audience might misunderstand in several ways. This is why commentators defending this practice also acknowledge it as just an attempt to re-present a potential aspect of reality, not to re-present reality itself.

Re-presenting biological processes by mapping them onto another non-biological process
Michael Wang's artwork "Differentiation Series" is considered a good example of creating a pictorial metaphor to illustrate a biological system by projecting it onto another non-biological system (Fig. 1B). Wang used a pigment-mixing system to illustrate the artistic correlation between cellular differentiation and the idea that stem cells can be induced to become any cell in the body, and colour theory, as white light can produce any colour on the spectrum. He produced a pigment-mixing system that produced 411 colours, equalling the most comprehensive list of identified cell types in the adult human body, and deployed a colour-coding system to paint each cell by hand (Wang 2012). Although this comparison used a non-traditional medium, its artwork took a traditional static form so abstract that it could not lead the viewer to a specific meaning because the core concept lies in the hidden process itself. While Wang attempted to illustrate biological differentiation as the target domain by differentiating white light as the source domain, a clear metaphoric deficit is observed because of the operational conflict between the target and Here, clear differences between the pictorial elements used to build a pure visual metaphor, and the abstract composition produced as a result of a processing a metaphor based on real operational processes of a non-biological system. But at the end, both examples have been shown in a traditional canvas with a static medium such that they cannot be categorised as bio artworks source domain. Thus, the cognitive framework here reflects a symbolic relationship, not an operational one. Further, his idea oversimplifies cellular differentiation, which cannot easily occur because several factors can interact and control it. Here, an operational conflict arose from comparing a non-living and living medium. The non-living medium, white light, can be manipulated and controlled under constant conditions, but the living medium possesses an autonomy that makes controlling it inconstant and without a guaranteed result.
Although these two kinds of pictorial metaphoric structures cannot operationally satisfy the conditions of being bio-artworks, they do say something, albeit within the limits of their medium and genre of practice, as paint in the first example and mixed media in the second.

Operational metaphor-based practices
Operational metaphor-based practices mostly belong to multimodal metaphors that present cultural, political, or ethical issues of biological processes. As real bio-artworks, they are mapped onto real biological processes that reflect a concrete concept, allowing the audience to understand the potential consequences of the implementation of such processes. Here, the source domain is usually embodied in a living material/process, and mapping processes are conducted during the lifetime of these processes. Hence, interactions between living material and the artwork's system, which implies that the target domain constitutes an ephemeral processbased art of transformation in vivo or in vitro, allows the audience to experience it emotionally and cognitively (Hauser 2006). Although bio-artworks executed with operational metaphors can offer the audience a real experience, unlike pictorial metaphors, they might apply real biological processes in a context that sometimes misguides the audience in understanding the extent to which biotechnology can control our bodies. 8 Alternatively, bio-artworks might (playfully) exaggerate the ease of manipulating living material, ignoring extensive related moral, cultural, and societal issues. A discussion of several of these approaches follows.

Presenting biological material by mapping it into a pictorial image
Alexander Fleming first introduced this approach in his bacterial painting on paper, although he did not intend his work as an artwork ( Fig. 2A). However, in 2006, at Roger Tsien's lab, Nathan Shaner created a well-known piece of this kind of bio-art practice (Fig. 2B). He drew a San Diego beach scene using an eight-colour palette of bacterial colonies expressing fluorescent proteins derived from green fluorescent protein and red-fluorescent coral protein (Berezow 2016). With this method, Shaner provided a living sketch-traditional in its pictorial elements but non-traditional in its medium-through which the drawing grows, changes, deforms, and so on. Similarly, in 2016, Michael Shen and colleagues developed the pictorial scene "Skyline of New York City" by printing nanodroplets containing yeast onto a large agar plate (Fig. 2C). Each dot in the scene was a separate yeast colony. As the colonies grew, a picture emerged, creating "yeast art" (Technical-Yeast Art 2016). These practices highlight the crucial role of the medium, which transfers a traditional pictorial scene into a living environment in which nothing can be constant. Nevertheless, such bioartworks may imply how easily biotechnology can be manipulated and controlled (Shen et al. 2019). Furthermore, this practice usually attributes the artwork's value to its biological processes: The pictorial scene here, as the source domain, is just a junk image 9 used to embody biological techniques as the target domain. As such, Yetisen and his colleagues emphasised that such processes refer to blurred boundaries between art and modern biology, so the experiments could be seen only through a biology lens 10 (Yetisen et al. 2015). Within this context, Junk image refers to the pictorial elements employed in this composition to embody the living material. So, these elements have nothing to do with the concept behind these artworks because their core concept is in the living material itself. This is why the pictorial image here is described as a junk content. 10 A lot of bio artworks, made by scientists, presented biological material by mapping it into a pictorial image as the easiest way for a scientist to get his/her experiment out of its scientific context and reconfigure it in another context which fit to be seen as an artwork. However, we should realize although the operational conditions of this metaphoric structure are satisfied as bioart, it cannot be the ideal example of a bio artwork as the pictorial images that embody the biological material is very traditional such that the power of the medium is much more than the power of its image, while in the ideal bio artwork both must have equal power at least if the final image was not the strongest to keep the artistic values.

Presenting a biological concept by mapping it onto biological processes
The distinction between organic and nonorganic, alive and dead, and human and nonhuman is a basic, complicated question bio-art addresses by adopting several approaches for designing operational metaphors that map the concept of life onto biological processes to synthesise living or semi-living elements. Adam W. Brown's experiment "Origins of Life" is a good example (Fig. 2D). The experiment shows how bio-artwork can present live processes instead of living material-as a target domain-through the dualistic argument between vital and mechanistic by mapping the concept onto a hybrid biological installation system-as a source domain-as minimal ecosystems theoretically capable of forming the self-organising chemistries needed to produce semi-living molecules and protocells (Brown 2010). This experiment was rooted in an experiment in the 1950s by chemist Stanley Miller, who filled an apparatus with hydrogen, methane, and ammonia gases in the presence of water vapour and subjected them to a repetitive lightning-like electrical discharge (Bada 2015). In collaboration with Robert Root-Bernstein, Brown extended Miller's experiment by adding means to resupply the system with fresh gases, water, and minerals to overpopulate the system's chemical species. Overpopulation drove chemical syntheses in new directions, so the system obtained not only amino acids but also sugars, fatty acids, lipids, nucleic acid bases, and ATP, the entire range of chemical compounds needed to build cell constituents. In this experiment, the metaphor works well at the functional and operational levels. However, its cognitive frame might raise conceptual conflict between a vitalist, who believes that 'life' consists of something special or unique outside the material world and cannot not be found by taking a living thing apart (holism), and a mechanist, who believes that 'life' can be explained by physico-chemical processes that are deterministic, mechanistic, and understood from the study of their parts 11 (Allen, 2005).

Presenting social or political issues by mapping them onto biological processes
Although mechanists' perspective towards living organisms has led to several advanced experiments supporting in vitro approaches to controlling living processes, their experiments gently challenge the free will of living material, one of the most important characteristics of a bio-artwork. That is, bio-artwork has the level of autonomy needed to grow and divide. In this context, Ani Liu created the interactive bio-artwork "Spermatozoa" (Fig. 2E). She designed an operational metaphor to demonstrate her power of control in response to President Donald Trump's 2017 executive order to cut all United States funding to international nongovernmental organisations whose work includes abortion services or advocacy (Liu 2017).
Martin Belam commented on the photo of the president signing the order, "As long as you live, you will never see a photograph of seven women signing legislation about what men can do with their reproductive organs". In response, Liu delivered an inverse metaphoric message to demonstrate that women can control men's reproductive organs by employing neural data from the brain to control sperm. She used galvanotaxis, in which cells migrate towards a specific charge in an electric field. She used a brain-computer interface to read electrical signals in the brain, which were then translated into commands for a microcontroller that moderates the charge on a circuit on which semen is placed, thereby directing the motility of sperm.
All previous examples of operational metaphors were constructed as dynamic systems that deliver real presentations through which source domains were mapped onto target domains. However, some dynamic metaphoric structures still refer to an operational unbridgeable gap between the source and target domains. This is because source domains are only a helping factor through which the audience's attention can be focused on the target domain, which is invisibly understood in the context of artworks. Although the previous examples can actively integrate the lay audience into many critical debates, they cannot accurately reflect what biology can or cannot do because most previous operational metaphors overestimate their approach's applicability to real life. Therefore, the lay audience's evaluation of most issues related to bio-artworks is usually unfair, reflecting them as better or worse than they actually are. However, observing a level of metaphoric deficit in some cases of the artworks' cognitive frames due to their operational metaphoric structures cannot destroy the artistic value derived from their conceptual ideas as real bio-artworks, which usually live in abstract relationships with their dynamic morphological compositions or installations. 12

Bio-media and post-metaphoric shift
In the current context, the term 'bio-media' refers to an important product of convergence technologies. Through this product, many cutting-edge techniques and scientific methods have been developed to overcome conceptual, technical, and operational boundaries between several domains. This enables the merging of different sciences to obtain cross-cutting technologies (Ahmedien 2019). Unlike biomaterial, bio-media cannot be pure biological material. Rather, it is defined as manmade biological media that emerge consequent to the interactions of heterogeneous systems derived from interdisciplinary biological and non-biological domains, often referring to synthetic biology (Meng and Ellis 2020).
Although the French biophysicist Stéphane-Armand Nicolas Leduc likely first used the term "synthetic biology" in 1911, modern synthetic biology is rooted in several mutually interactive fields. This is based on applications of convergence technologies in engineering, computing, and modelling with molecular biology, evolutionary genomics, and biotechnology on one hand, and research into the origin of life, artificial life, and orthogonal/parallel life on the other (McLeod and Nerlich 2017). Therefore, although bio-media could be considered a living or semi-living medium, the term was operationally recognised in synthetic biology including biotechnology and bioinformatics applications and products. Through these, boundaries between natural and artificial life can be mitigated and biological media can be sustained, modified, and re-synthesised via various digital means (Porcar and Peretó 2018). Therefore, influenced by extended techniques and applications of today's synthetic biology, several bio-media trajectories emphasise a high level of digitisation and proliferate in a wide range of biological processes such that an informatic paradigm can pervade the biological notion of the body and biological material (Davies 2019). Therefore, as mixed media, biomedia operationally raises radical questions about the meaning of life and what makes us human.
As such, through today's convergence technologies, several previously longstanding operational metaphors illustrate that biological processes might be moved from mere metaphor to reality in synthetic biology (Stelmach and Nerlich 2015). As mentioned, if digital practices in bio-art were considered pictorial metaphors because of non-living material embodying the source domain, operational metaphors influenced by synthetic biology could decouple the two paths that deal with biological substances: the purely biological path that occurs when dealing directly with pure biomaterial and the digital path when dealing with genetic code in its digital state. Here, the differentiation between biomaterial (used in previous examples of operational metaphors) and bio-media must be identified in the differences between complementary and embedded relationships. While using a pure biomaterial might be complementarily supported by any digital or technological means to sustain its process, a bio-media could be a biological system that contains digital properties embedded in the medium's function. As such, the operational gap demonstrated previously between the source and target domains could be reduced if the source domain is contained in the target domain and vice versa, instead of being two separate entities. Thus, bio-media have led to conceptual shifts in the structure of operational metaphors, through which digital properties (as a source domain) can facilitate a qualitatively different notion of the biological body (as a target domain) that is technically articulated and fully biological (Merritt et al. 2020). This framework could lead us to further operational metaphors that imply a high level of coherence between digital media and bio-media, which are mutually embedded and exchange roles in the structure of a multimodal dynamic metaphor.
During the last decade, cutting-edge applied synthetic biology research has for biological and non-biological purposes, achieved a biological paradigm shift in producing bio-media as products and media by which a biological substance is reused operationally through digital processes. Hence, three major operational metaphors have transformed from mere metaphors to real processes, or at least applicable metaphors when they are reprocessed as bio-media. Here, the source domain is a dynamic system functionally embedded in the target domain's operational properties. Thus, the operational correlation between the source and target domains can be fundamentally redefined in three bio-media products, as explored below.

Genetic language
The biological-linguistic analogy can be traced to Darwin's "On the Origin of Species". Darwin designed a purely conceptual metaphor when he used language as a source domain to illustrate the concept of species as a target domain. He stated that they both evolve through time and under geographical constraints, and both undergo a process of evolution based on a low level of constant change (Bralley 1996). Despite the gap between human language structure and DNA structure, defining DNA as a language is one of the most influential metaphors, broadly permeating collective public understanding. Gemma Bel claimed that genetic code and natural language share a number of units, structures, and operations so that syntactic and semantic parallelisms between these codes should lead to methodological exchange between biology, linguistics, and semiotics (Cantero 2012). In this regard, the linguist Jakobson introduced the first relationship when he suggested an interpretation correlating elements of genetic code and verbal language (nucleotides against phonemes/letters, codons against words, and lexicon against 64 codons) (Leung et al. 2001). In a further step, Lyons more closely examined the molecular-linguistics analogy by considering four essential design features that enable language to function as a signalling, or semiotic, system: discreteness, arbitrariness, duality, and productivity. Later, Collado-Vides used a generative grammar model 13 to analyse gene regulation (Bralley 1996).
Although calling DNA a language has allowed reading genomes as possible literature or poetry in the form of two linguistic symbolic systems in previous attempts, another technical approach exists to introduce the operational metaphor between DNA and programming language as two signalling systems. Technically, mapping DNA sequences onto human language raises a fundamental operational conflict. This is because letter sequences in human language refer to meanings in our collective cognitive memory, while DNA sequences are strings of bases' "nucleotides" A\ T\ C\ G that refer to numerous chemical interactions, which produce a myriad of proteins that make us who we are as a species and guide our growth, development, and health as individuals (Chatterjee and Yadav 2019).
Nevertheless, this operational conflict could be mitigated by replacing human language with a programming language. In fact, several commentators emphasised that both DNA and programming codes are operational processes based on signalling systems, and both can be interactively synthesised and combined under several interdisciplinary applications in synthetic biology. 14 In this context, several biologists and computer scientists have developed a nucleic acid-based programming language, jointly improving an algorithmic understanding of the behaviour of genetic regulatory networks behaviour towards developing an applicable genetic linguistic model (Spirov and Myasnikova 2019). In this regard, David B. Searls emphasised a common function between the genetic-based database, in which a gene is the basic unit of living organisms, and the programming language database, in which a bit is the basic unit of digital organisms (Dong and Searls 1994). Searls' vision has been confirmed by several research projects conducted to digitally contextualise this nucleic acid-based linguistic database. In 2016, biologist Riccardo Sabatini and colleagues wrote the first printed book to transcribe a person's genome. In font size 8, the genetic book comprises 262,000 printed pages in 175 volumes of 1600 pages each (Falleni 2021). Writing this book using the four-letter language of DNA implies that as a signalling system, the sequences of these letters could be used to narrate an individual's biological script. In this case, the source domain (function of the signalling system) is embedded in the target domain (the assumed chemical reactions expressed by the four letters of the same DNA as a signalling system). 15 Here, the sequence of the DNA letters is not biomaterial and not living material but a bio-media. Real human DNA sequences have been analysed and scripted by DNA's four-letter signalling system to document the individual's biological identity as a book that serves to mediate that story.
Here, the story is written in genomic bioinformatic language; however, it is not the human genome, but merely a symbolic language. This course of practices can be historically traced in new media art in Joe Davis' work entitled "The Riddle of Life" from the 1980s. He used DNA as a language based on Delbrück and Beadle's ideas for expressing human language in the form of DNA 16 (Ars Electronica 2000). Davis created DNA corresponding to Max Delbrück's toothpick molecule. While regarded as a developed method in his time, it cannot be considered among the post-metaphoric structure adopted by today's bio-artworks, as its source domain 14 Within this context, both computer programming code and genetic code have something to do together in synthetic biology that may combine both in several interdisciplinary investigations. For instance, when computer scientists and biologists jointly perform common inquiries to understand the genetic regulatory network. However, this does not mean that genetic code and computer programming code are the same, or they do the same job, or even they can fully exchange their roles. 15 Within this context, perhaps the cutup theory by William S Burroughs Coincides with his concept of Language as a Virus. 'Cut up' is the deconstruction of a primary text using the random cutting up of words and phrases to form new sentences and thus a new piece of writing. The rediscovery of the technique is thanks to Brion Gysin, who showed the method to William Burroughs and he, in turn, spread it among dozens of musicians and artists under his influence. These techniques could be reformulated at genetic level by CRISPR-Cas technologies that may be used to cut up DNA and rephrase it within another context. 16 In the fall of 1958, the biophysicist Max Delbrück sent a mysterious telegram to George W. Beadle, who was in Stockholm to receive the Nobel Prize. The way in which Delbrück wrote his telegram reflected some of the new, exciting ideas about the nature of DNA and the functioning of the genetic code. At the same time, he anticipated the idea that extra biological information-in this case the English language-might be able to be contained in a genetic form. The telegram consisted of a single ‹word› with 229 letters. is a symbolic composition without real functional embedding into the target domain, which is invisible. In this context, many new media artists tried to develop multimodal dynamic operational post-metaphoric structures depending on the processes of transferring text as the source domain to DNA as the target domain, and vice versa. Although some of these attempts are predominantly linguistic, playfully less defined, more poetic, and equally incomprehensible, several prominent experiments in sonification employ genetic information at a similar mature level of signalisation.
In recent artistic practice investigations related to claims of a connection between DNA and programming language, new media researchers at the Massachusetts Institute of Technology (MIT) developed a source domain as a system that converts a real molecular protein structure into audible sounds that resemble musical passages. This is an attempt to gain insight into the genetic code's 'language' (as a target domain) that governs protein functions. The system translates the protein's amino acid sequence into an encoded musical sequence of tones, and then returns these tones to rebuild the protein's amino acid sequence to decode the protein's functions by recomposing new proteins (Fig. 3A). The researchers programmed a free Android smartphone application, "Amino Acid Synthesizer", to play the sounds of amino acids and record protein sequences as musical compositions (Yu et al. 2019). They designed a multimodal resemblance-based metaphor in which similar ontological types intervene and work in two directions. Therefore, the operational process of synthesising music into the protein's amino acid sequence is strongly integrated, and the two can be converted to each other. Thus, considering this process, a mere

Genetic storage
Francis Crick and James Watson are considered the first scientists to use words such as "information" to describe the processes of protein synthesis (Watson and Crick 1953). However, their use of such terms was metaphoric, inspired by similar use in the mathematical theory of communication where "information" refers to quantitative signals but the qualitative meaning of such signals is irrelevant (Cobb 2017). Indeed, information theory provided modern genetics with a range of terms such as "genetic code" or "code of life", fully utilised when geneticists explain their work to those outside their field. In addition, these metaphors drew scientists' attention to the DNA structure's possible operational function, not as a material but as a medium (Annas 1993). Therefore, scientists proposed the validity of DNA as a reproducible medium in which a sustainable amount of information can be included. Nozomu Yachie and others argued that the development of DNA memory technology utilising living organisms has much greater potential than any existing counterparts to render a service of inheriting data (Yachie et al. 2008). Hence, various codes have been developed for encryption in DNA sequences, such as the economical Huffman code (based on Huffman's algorithm) for short-term data storage and other codes for long-term storage. Finally, by adopting cutting-edge techniques that have emerged from CRISPR-Cas gene-editing technology, images and movies can be encoded into a living organism.
In July 2017, a team of Harvard scientists directly encoded a series of images taken by Eadweard Muybridge into the DNA of living E. coli to develop a molecular recorder that can remain within living cells and collect data over time (Shipman et al. 2017). After just one year, a team of Swiss scientists proposed a concept for developing a prototype molecular recorder for a cell to self-record all its genetic activities (Schmidt et al. 2018).
Thus, describing DNA as a carrier or saver of information is no longer merely metaphorical, because a real operational approach defines the information-storage function as a source domain embedded in the properties of DNA as a target domain. Historically, some experiments in new media art were conducted to investigate the use of DNA to store data. Examples include Joe Davis' Micro Venus experiments in the 1980s and subsequent projects where the artist created a coded visual icon representing the external female genitalia genome to integrate it into a hardy strain of bacteria and send it into deep space. This symbolic approach was operationally developed later in some experiments (Davis 2000). For example, Kac's GENESIS is a synthetic gene created by translating a sentence from the biblical book of Genesis into Morse Code and converting it into DNA base pairs according to a conversion principle specially developed by the artist for this work (Tomasula 2002). Currently, to emphasise DNA as a bio-medium that functions even for non-biological purposes, the artist Pierry Jaquillard, in his experiment "ACGT", used his own DNA (chromosomes 1-22 and XY) as a target domain and five custom-made interfaces as a source domain to understand his core structure's natural code and its relation to the artificial code he had written (Fig. 3B). Jaquillard wanted to see what as a gene-based unit, his personal data contained and whether a bit-based unit could re-compose it as a reservoir of the pieces of music through which the source domain was mapped onto the target domain. In his experiment, two devices drove the interaction, and the remote allowed the user to change parameters such as tempo, musical arrangement, or type of conversion and chromosome library. The user could choose what to play and find its location in this library. Thus, Jaquillard expanded the metaphoric expression "chromosome library" beyond pure metaphor when the term "library" gained an operational interpretation in his DNA system (Visnjic 2021).

Genetic reprogramming
Over the last two decades, biologists' development of the concepts of rejuvenation and cellular reprogramming has demonstrated the validity of applying the "reprogramming from scratch" metaphor to the cell (Liu et al. 2019). In 2006, Shinya Yamanaka showed that adult, fully specialised mouse cells could be reprogrammed to become cells that behaved similarly to pluripotent stem cells-"induced pluripotent stem cells"-that can develop into all types of cells in the body (Yamanaka 2012). Thus, stem cells operationally support the reprogramming metaphor since the process of reprogramming from scratch presents a source domain and the process of differentiating stem cells is the target domain.
Although reprogramming usually occurs at the molecular level, the related concepts might be historically traced in new media arts within the developed operations of re-synthesising and redeveloping the entire human body's architecture. Over a period of around 12 years, Stelarc developed a radically iconic example, namely "Ear on Arm". Stelarc assumed that altering the body in a way that requires engineering an alternative anatomical architecture might mean adjusting its awareness, which might also be performed telematically. Operationally, the ear was equipped with a Bluetooth receiver and microphone, allowing the artist to communicate via mobile communication directly into the ear. The speaker was placed in his mouth, allowing Stelarc to "hear" whoever was speaking to him from within his own mouth cavity (Abrahamsson and Abrahamsson 2007). Because Stelarc examined the human body's architecture via his own body, the source and target domains cannot be separately defined. They were mutually inclusive, namely the non-biological equipment-like sensor and Bluetooth embedded in the biological function of the third ear, which is described here as a bio-media not as a biomaterial.
While Stelarc used a living material to architect a living object in this project, and its extension entitled a ¼-scale ear, 17 in a further step, biophysicist Andrew Pelling used non-living material to re-architect the same object but in a semi-living form. Pelling engineered a prototype human ear from apple cells by hand-carving an apple into the shape of a human ear and injecting human cells into it. Within weeks, the cells infiltrated, transforming the chunk of apple into a fleshy human ear (Dance 2021). In contrast to Stelarc, Pelling conducted his experiment using nonhuman material (apple) as a source domain to examine the extent to which human cells could interact and sustain their processes in the apple's body. However, as a target domain, the synthesised artificial ear cannot be viewed as a purely metaphoric structure, because the ear becomes a bio-medium re-synthesised from an inseparable biosystem of real human cells and the apple's body. As such, the source domain was processed to lead into the target domain. Although these applications have achieved a paradigm shift in the structure of operational metaphors used to embody concepts in these bio-media-based artworks, synthetic biology has taken further steps at the molecular level to shift the metaphor from re-synthesising to reprogramming. Operational approaches of biological/cellular reprogramming fundamentally emphasise the validity of gene-bit duality metaphors used jointly for biological and digital media. These double-faced metaphors operationally facilitate communicative dialogue between the worlds of genes and bits; thus, the DNA structure might be described as the encoded instructions of a function written from scratch and uploaded to a living cell to perform the required function. Commercially, several biological companies produce ready-to-use differentiation kits for reprogramming and/or differentiating stem cells into any type of cell. Indeed, an MIT team designed a project titled "Cello" (Fig. 3C) to allow specialists to develop DNA circuits that would translate their inputs into a DNA sequence, which when placed in a cell, would execute their requirements (Nielsen et al. 2016).

Concerns for the future
As demonstrated here, biology's epistemic landscape as exported by bio-artworks has developed throughout the history of bio-art. Categorising metaphors in bio-artworks might be based on the relationship between source and target domains as a model adopted to bridge them and control the quality of the epistemic landscape exported to the public.
Pictorial metaphors do not essentially belong to the bio-art genre, as they usually suffer operational conflict between source and target domains because they represent 17 A different strategy has been pursued in attempting to realize the EXTRA EAR project. In collaboration with Oron Catts and Ionat Zurr of Tissue Culture & Art a 1/4 scale replica of Stelarc ear has been grown using human cells. A cast of Stelarc ear was made from which a scaled down biodegradable polymer scaffold was produced. The scaffold was seeded with living cells and the ear was cultured in a rotating micro-gravity bioreactor which allowed the cells to grow in a 3D structure. The incubator was kept at 37 C. The ear was fed with nutrients every 3-4 days in a sterile hood. 1/4 scale ears have been grown with human donor cells, the cells of the HeLa cell line and mouse cells.
only a radical debate about a biological concept using a traditional or non-biological medium not operationally parallel to that of the target domain. Although operational metaphors use biological material to avoid operational conflict in pictorial metaphors, an operational gap still exists because the biomaterial embodying the source domain is usually employed in contexts separate from the actual concept of the target domain. Finally, influenced by synthetic biology, bio-media products introduce another radical metaphoric structure that can be described as post-metaphoric, in which the source and target domains are mutually embedded. That is, two unified, dynamic systems can exchange roles; thus, convergence between the source and target domains is no longer merely metaphorical but (almost) real.
In this regard, this metaphorical framing may be used as a diagnostic tool, as it allows us to take stock of its many varieties and categorise the amorphous field in terms of the gaps between source and target domains, for example. However, this reading also helps us understand problems with the field. For instance, a dangerous consequence of the post-metaphoric epistemic landscape in today's bio-media-based art is that it obscures the evolutionary and developmental complexity of biological systems in treating organisms as reducible and interchangeable parts. This is because most approaches designed to bridge the source and target domains concentrate only on operational processes, meaning that the human body can only be understood as the sum of controllable biological materials and processes. This might implicitly reinforce genetic determinism, which challenges individual free will. Indeed, several commentators have emphasised that the operational processes of metaphors in synthetic biology could reduce life to the sum of physics, chemistry, and information in biotech applications. For instance, using DNA as a storage means may lead us to realise that the missing experiment is to see how the information hidden in the genomes of the organisms might be expressed instead of used as a readback device. In other words, the real meaning of the data is arbitrary compared to the morphological or metabolic effect of a database that has gene action promoting it downstream into the evolutionary anatomy of the storage device.
Consequently, metaphors in biotech and synthetic biology-based bio-media could lead us to a completely different paradigm of the human body's material, even to a commercial paradigm. If genes are understood as an individual's essence, they might also be defined as a commercial product, implying that the human body's genes would eventually become for sale. Could such insight into genetic trade show us a biological extension of the history of human trafficking in the future? This ambiguous situation could raise several radical questions regarding legal and moral frameworks to define genetic material as persons' valuable property and the extent to which they can control their genes.
In fact, human beings cannot be reduced to the sum of their genetic instructions, because 'epigenetic factors' such as individual behaviour and the surrounding environment can cause changes that affect how genes work. Hence, most previously discussed examples, particularly bio-media in their post-metaphoric structure, ignored epigenetic factors when exploring the gap between the source and target domains. For instance, when Riccardo Sabatini wrote the entire DNA sequence of a man in a 262,000-page book, he operationally demonstrated the post-metaphoric approach to validating DNA as a bio-media-based linguistic signalling system. However, this book is not a man's genome. Likewise, when Jaquillard investigated the content of his chromosomes, he examined the properties of his genetic material, not his human identity, which is much greater than mere genetic information. This is how a conceptual barrier in the post-metaphorical structure of bio-media-based artworks might be found.
Today's cutting-edge convergence technologies have made dramatic progress in mitigating the operational gap between the source and target domains in operational multimodal metaphors. However, conceptual barriers between these domains are permanent factors due to the chaos of bodily heterogeneity attributed to manipulating biological systems by artificial life, artificial intelligence, virtual reality, genetic algorithms, or bioinformatics techniques where digital technologies dominate. Nevertheless, the operational values of the post-metaphoric epistemic landscape could address this gap depending on the extent to which the designed metaphor can deliver non-predetermined content. This would afford the lay audience a chance to interact during mapping processes and flexibly control the relationship between the source and target domains. Bio-media-based art has a great potential to construct more productive, dynamic, and multimodal post-metaphors, not only addressing the operational convergence between the source and the target domains, but also empowering their functional capabilities to support human body functionality. An example is the current interdisciplinary endeavours devoted to enhance data exchange between digital systems and human bodily systems leading to several actual applications, such as but not limited to producing sets of bio-tattoos that could be drawn on the body to monitor its functionality and analyse and deliver information regarding bodily performativity.
Within this functional context, bio-artworks based on the post-metaphoric structure could be a powerful joint space for artists and biologists when the metaphor's architecture allows both parties to share and discuss thoughts and actively integrate the lay audience. In this case, the source and target domains must be embodied in an open, dynamic system through which the lay audience can honestly witness the gap. For scientists to fill this gap, it must be defined as a cognitive stimulus. Addressing the gap should happen in an interdisciplinary space where several disciplines can comprehensively fill it. Therefore, addressing the gap requires cross-cutting techniques, encourages convergence technologies, and permits a radical shift of the concept of the target domain. Although these challenges seem far, monitoring the history of developments of every yesterday's metaphor-from its pure metaphorical state to its status under the post-metaphoric structure-reflects how dramatically humans' free will has enabled us not only to understand but also to partly control nature. Just as several of yesterday's metaphors have become today's reality, many of today's metaphors can be expected to become tomorrow's reality. 18