© SCF, 2023

1 Introduction

This article discusses the nature of materials. It is a “free expression” document, presenting an intuitive rather than a tightly-knit argument. However, it was given in a symposium dedicated to Leiv Kolbeinsen, an intuitive and creative person, so that it seemed like the perfect place for this kind of experimental narrative.

Materials have been ubiquitous since homo sapiens emerged on Earth. This is why materials are important for mankind or for society, like energy, if one thinks as an engineer or an economist, like life and death, hate and love, from a simpler human perspective, like space and time, from a philosophical one.

A simple definition of materials is that they are matter transformed by people for their own usage: materials help people build the anthroposphere, in terms of structure and function. Matter stems from the geosphere and the biosphere: thus, materials connect the three ecological spheres. Moreover, materials are not simply physical matter, they are matter transformed by people, a first simple definition of what we shall call later a social construct.

They are many possible narratives about materials, and a list of such stories is given in Section 2.

One narrative consists in looking at materials as they stand at any given time, today for example: linguists or historians would speak of a synchronic vision of materials.

Another narrative consists in looking at materials as they have been “traveling through time”, from prehistoric hand tools to modern materials. This is a diachronic vision of materials.

There is a credible claim that there is a continuity between materials at different points in historical time: for example, modern concrete is the present avatar of Roman cement and, maybe less clearly, of Paleolithic tools such as a hand axe (biface). Common materials are thus given a genealogy or an etymology that penetrates far back in time.

Common materials are called structural materials today, as opposed to functional ones. See further.

Thus, we have two visions of materials that paint them both as old and new at the same time. This dichotomy has preoccupied me for a long time. I saw it at times as a contradiction, an aporia or a conundrum, and I have been trying to resolve it, assuming that it could be done usefully.

Hence, the presentation will have 3 parts: the synchronic view of materials, then the diachronic one and finally the view of materials as actants in an ANT world – vocabulary and concept to be explained later – as an attempt to resolve this tension. Indeed, as we will try to show, materials assume a proactive role in their own perenniality.

2 Synchronic views of materials

We present here a series of contemporary stories about materials, thus a synchronic view positioned today.

1. Materials can usefully be described in the context of the three ecological spheres, anthroposphere, geosphere and biosphere. This refers to a wholistic model of the world, comprising both nature and society, based on an ecological narrative that merges natural and industrial ecology together. This is the simple way that space is taken on board in our analysis.

2. Materials are described as part of a sustainable world – or one that strives to be sustainable – driven by ethical, motivational, political and business motivations. The connection between materials and sustainability, however, is not obvious and it extends beyond the story telling of Corporate Sustainability Reports (CSR), some of which is no more than plain greenwashing. Moreover, there is a discipline called LCA, which generates long lists of environmental burdens due to industrial artifacts, to technologies in general and therefore to materials. Hence, there is plenty of room to articulate the various burdens brought about by materials and there is a clear need to do so and look for answers. This is the simple way that time is taken on board in our analysis.

3. Materials are numerous and diverse. They are competing with one another, while being also complementary, assembled as they are in most industrial artifacts.

4. Materials interact with the environment at their surface, which constitutes the first boundary with the ecosphere, i.e. biosphere and geosphere. Corrosion mechanisms take place, interacting with behavior, mechanical properties, lifetime of artifacts, etc.

5. Materials serve as barriers between human space and nature. Thus, between the anthroposphere and bio, geo and techno-spheres. This is true of walls, of clothes, of cars, of reactors in a plant, etc. Materials have the property of sustaining gradients of properties, such as temperature, pressure, stresses, chemical potentials, electrical potentials, etc., which are called insulating behaviors of various kinds. This is the first set of features that make structural materials what they are.

6. Materials ensure that artifacts are perennial, that they endure significant lifetimes. This is true of a tin can or of a building, especially a heritage historical construction. This is the second major feature of structural materials.

7. Materials that contribute to producing services provide first technical services as defined in their specifications, but also social services (like a bridge spanning across a deep valley provides transportation services to people, cars, trucks and trains) and eco-social systemic services, somewhat similar to the ecosystemic services of biodiversity.

8. Materials are made – like in the word ironmaking – from raw materials and from fossil fuels extracted mainly from the geosphere. Resources were long assumed to be infinite, but now a major issue is related to the scarcity of some of them (many and more and more), which are called critical raw materials. The criticity of materials is therefore one of their important features.

9. To assuage the burden of relying on natural resources, one important feature of materials is their circularity, i.e. their ability to be recycled and more. Circularity is an essential paradigm related to materials but also to the resilience of the economy

10. Making materials and also using them is energy intensive – because most of them do not occur natively in nature in sufficient quantities – and generates large amounts of GHG. Hence, a strong connection with Climate Change and the ecological transition.

11. There are complex and subtle connections between materials and biodiversity.

12. Materials production generates emissions to air, water and ground, which need to be abated and may or does lead to pollution.

13. These processes generate particulates and organic and inorganic molecules that interact with life, when they are toxic or ecotoxic. Toxicity may also be a feature of the materials themselves. Air pollution is responsible for 4.5 million premature deaths per year.

14. Materials are deeply contemporary creations and, if producers and associated researchers are to be believed, they are also continuously innovative. The innovation narrative is important for them.

15. Note that an important technique for describing materials “as they are” in their synchronous persona is LCA (Life Cycle Assessment): it presents a series of indicators, which, when applied to materials, outline most of their major features described in this section [1,2].

3 Diachronic views of materials

1. There is a classification of materials that stems from their historic emergence in the stream of time: stones, ceramics, copper, bronze, iron, etc., until silicon. This leaves aside textiles, wood and bio-sources materials (bones, antlers, etc.), which were not included with these categories of materials.

   1. The time scale of Prehistory was organized, in the early 20th century, according to the materials that were used at a particular time: thus, the Paleolithic, the Neolithic, which refer to various types of stones, the age of copper or chalcolithic, the age of bronze and the age(s) of iron, which refer to metals. Today, the expression of age of silicon has been proposed.

   2. This does not mean that each eponym material was the cause of the transition to the period that bears its name, but, rather, that the material was sufficiently ubiquitous during that period, that it became an easy marker to identify it: there was thus simultaneity, but no causal link. Note that there was probably a misunderstanding in the role of material when they were proposed to name periods and that this ambiguity remained in education for a long time.

   3. Note that these periods were named before the evolution of hominidae and the emergency of Homo Sapiens were clearly understood, so that the earlier tools of the paleolithic were made by Erectus and passed on to Neanderthalis and then to Sapiens with appropriate changes and evolutions.

2. The order in which metals were used was, for a long time, supposed to be related to their affinity to oxygen, i.e. to the difficulty of scavenging the metallic metal (M^o) from ores, often oxides. Thus gold, a precious metal was deemed to have come first, closely followed by silver. Then came copper, which existed as a native metal, just as the precious metals did. Copper was smelted later in time, i.e. made from ore reduced by carbon from charcoal. Copper was then alloyed with arsenic and then with tin to make bronze. Iron arrived later and it was also smelted, as native iron from meteorites was extremely rare. In Ancient Times (Middle East and Europe), seven metals had thus been invented: gold, copper, tin, iron, lead, silver and mercury. Note that China was more or less at the same level of understanding of metallurgy than Europe and the Middle East and the 7 metals had their own ideograms in old Chinese and in modern Japanese. Pre-Columbian America was satisfied with using only gold, silver¹, copper and bronze before the arrival of the European. India developed more or less parallel to China. This model of how and when metals entered “civilization” was proposed by Agricola in the 15th century.
   Note, incidentally, how these points out to the centrality of metals in the historical timeline: other materials are paid less attention, for objective reasons but maybe also because they stayed out of the radar: this is a point that would need to be investigated and analyzed further.

3. Metals were used initially as ornaments, then as tools, vessels (pots and pans), works of art, weapons² (cf. Fig. 1) and eventually machines, mainly since the industrial revolutions.

4. These simple ideas were tested experimentally, when numerous excavations were conducted systematically in Europe, in places where buildings or civil engineering structures were to be erected (under the auspices of INRAP in France). This led to the conclusion that although the general trend was indeed confirmed, it turned out that locally, metals were not necessarily used exactly in the Agricola order of merit. For example, bronze swords were used for a long time after the “invention of iron”, which remained a decorative material, as long as its mechanical properties were too mediocre to be used in weapons. Similarly, iron was smelted at least one millennium before the ages of iron of Hallstatt and La Tène in central Europe. The Hittites were credited with the first making of iron in what is called Anatolia today, but iron was also smelted in Africa (beginning of the third millennium), in China and in India, without any evidence of a center from which the invention would have diffused. The linear model of Agricola thus turned out to be in effect rather useless as an explanatory model of the detailed mechanisms that controlled the apparition of the various metals in human societies.

5. As calendar years clicked along, no new elements and particularly no new metals were discovered until the end of the 18th century³, when chemistry came of age, and led to the formulation of the concept of chemical elements by Lavoisier as we know them today⁴. Immediately afterwards, the number of elements exploded until they were organized in the periodic table by Mendeleev and then this structure was explained by quantum physics. See in Figure 2 the evolution of new elements along the historical timeline.
   The number of elements available to explain how the world functions and to generate more technological artifacts is clearly shown in this figure.
   Note, however, that (chemical) elements and materials are two different things. The multiplication of elements, until the table is full, did not systematically lead to new materials so that one would tend to say that materials are less numerous than elements: this, however, is not true, as, for example, there are thousands of grades of steel, thus materials made from iron. It is the number of structural materials which is limited, almost confined, as far as metals are concerned, to the 7 metals of ancient times: a few structural metals were discovered since then, like aluminum, titanium, nickel or tantalum, but most of the others are mainly used as alloying elements (Mn, Cr, Ni, Co, V, Zr, Si, etc.) or as functional materials. This is obvious in Figure 3.

6. Process metallurgy has always been an important feature of making metals. It also went through several historical stages. In the case of iron, it involved the smelting and then hot working of the bloom, in workshops named the bloomery and the smithery or the forge. Crucibles or shaft furnaces were used depending on the metal and the time. The reactors grew in size and in sophistication, when the bloomery evolved into a blast furnace, using bellows for example and reaching higher and higher temperatures until the furnace finally produced a liquid metal that was highly carburized, pig iron. This evolution came along with large increases in productivity of the workshops and thus with lower cost of metals. The details should be looked up in specialized articles and books. One should also be aware that this describes the evolution of process metallurgy in the West: China followed a different path and started to use the Blast Furnace many centuries before Europe⁵. A sophisticated metallurgical handicraft was slowly developed, which allowed to make purer and cleaner materials and to combine various kinds of iron-carbon alloys, for example, to make extraordinary blades like Damascus steel. What was true in Ancient Times and in the Middle Ages is even truer in modern and contemporary times.

7. Seen from afar, all what has been briefly outlined seems to demonstrate that a technological progress was in place in terms of elements and metals (among other things), based on the progress made in chemistry, which transformed into a modern science from the 18th century on. Note that scientific progress and technological progress are two different things, even if they are related. Moreover, both definitions of progress do not necessarily connect with that of societal progress, although, again, some superficial correlation is obvious (increase in population, in life expectancy, in gender equality, in GDP and in standard of living). We want to stress two more points, however: progress, if we accept to use that word, has been proceeding at very different paces and, thus not monotonously.

8. What is important to add in this section, is that materials, like most human creations, are socially constructed. This may not be obvious to the untrained observer, as this kind of statement results from a social science model called social constructivism, which has been developed and demonstrated in particular by Bruno Latour and is studied in STS (Science and Technology Studies) or SCOT (Social Construction of Technology). This means, in simple terms, that the driver of the invention of chemistry and the development of new materials was not progress per se but rather the fact that society at that time (European Society) was in needs of chemistry and of new materials to move forward (not necessarily upwards!). To understand the nuances and subtleties of this kind of statement, refer to the book of Latour on Pasteur and his inventions of vaccines [3].

9. Now if we look at the lineup of materials over thousands of years of human history, we realize that they show a deep continuity, cf. Figure 4 borrowed from M. Ashby [4]. Beyond the links made by Ashby between ancient and recent materials, which are explained briefly in the introduction and attest to the continuity, the diagram also shows that, in the first half of the 20th century, metals became dominant in terms of market share, but were “replaced” from there on by plastics, composites, glass and ceramics. This is an illustration of the competition between materials⁶, not necessarily an all-out war, but rather a complementarity and the fact that “new materials” fill in the increase in materials needs faster than metals. And since we are convinced by Ashby’s argument that the “new materials” are not really new but stem from historical ones, we observe a historical respiration of the roles that all materials play in the Bayeux tapestry of time.

10. This kind of analysis supports the claim made by some that structural materials, and metals in particular, are old – an objective statement – and, furthermore, obsolete – a subjective one. This places materials in a marketing narrative, where new materials are seen as replacing older ones in a never-ending series of waves of new product. And it stresses the tension between old and new materials, thus between synchronic and diachronic views of materials.

11. The historical continuity between families of materials still remains a mystery at this point: why were metals not simply replaced by plastics or composite materials or graphene? Why is steel still sold at the level of 2 billion tons per year today, when bloomeries, which were only producing a few kilograms of iron, 2000 years ago, could easily have been forgotten? One can come up with many answers to this question, based on the “recent” understanding of what is a metal, as clarified by materials science and physics, or on the dynamic of innovation that often (never?) does not spring out of the blue, thus continuous vs. breakthrough innovations. These narratives, however, ought to be fleshed out in great details, not simply taken for granted. A different explanation will therefore be proposed in the next section.

12. Note that an important technique for describing material as part of a design process, i.e. in their diachronic persona, is SCM (Social Cycle of Materials): it describes how materials emerge in an exercise in design after a long process of proposing series of solutions to a problem until a closure is met by consensus among actors-stakeholders [5,6].

Fig. 1 Beating swords into ploughshares, a statue by Evgeniy Vuchetich at the United Nations in New York City. De l’épée à la charrue, une statue de Evgeniy Vuchetich aux Nations Unies dans la ville de New York.

Fig. 2 Discovery of elements along the historical timeline from year 0 to the 21st century. By 2020, all the elements in the table had been discovered (source: Periodic Table app, Royal Society of Chemistry, 2012). Découverte des éléments au cours de l’histoire, de l’année zéro au 21e siècle. En 2020, tous les éléments du tableau avaient été découverts (source : Periodic Table app, Royal Society of Chemistry, 2012).

Fig. 2 (Continued)

Fig. 3 The 52 elements used in a smart phone in 2021. Source: Ingénieurs sans frontières (CC BY-NC-SA). Les 52 éléments utilisés dans un téléphone de 2021. Source : Ingénieurs sans frontières (CC BY-NC-SA).

Fig. 4 Continuity of materials across historical time spans. Continuité des matériaux sur des périodes historiques.

4 Materials as actants

To reach beyond the previous argument, we will introduce the Actor’s Network Theory (ANT), a description of society proposed in the 1980s by sociologists and anthropologists belonging to the Social Constructivism school and to the field of the Science and Technology Studies (STS) [7–10]. ANT ambitions to explain how scientific and technological issues emerge in society at a given point in time: as materials are technologies [4] which have been related to science since Materials Science developed, ANT seems perfectly fit for discussing materials and answering ontological questions about them (where do they come from, etc.). ANT is a complex model that is explained in a variety of primary and secondary texts [7–9]. The names of the founders, Michel Callon, Bruno Latour and Madeleine Akrich, ought to be mentioned here.

1. ANT posits that technical objects emerge as the result of the interests of a series of actors, human but also non-human ones, which are called actants to give them a symmetrical position in the narrative. “This symmetry makes it possible to deal, at the same conceptual level, with: all the contextual factors; social and technical causes; the discourse of all the actors; humans and non-humans; as well as [partialities and] impartialities in recording the context. All the components of the socio-technical network intertwine without any hierarchy not distinction as to their nature. Technology emerges as the result of the constitution of a complex network of actants, which does not comply with any a priori logic but feeds on controversies” [11].

2. One of the strong and original features of ANT is that the network is a hybrid one, comprising not only human actors, but also non-human ones: thus, animals, trees, but also inanimate objects⁷. Hence, the word actant to replace actor. It may also include discourses. Moreover, ANT is not so much concerned with how well it matches scientific truth, but it’d rather make sure that all actants are taken on board, moreover in a symmetrical way.

3. LCA can be described in ANT terms [12], but only imperfectly: indeed, the ANT network in that case is the value chain, but there are no “actants” in LCA beyond a small number of human actors (the practioner, its client, a few other experts). LCA does also propose a translation [13], in the sense of Michel Serres, in as far as it transforms the input data into indicators, including midpoint and endpoint ones: however, it is a kind of procedural, automatic, mechanical translation, based on LCA methodology anchored in ISO 14040 standards, rather than the result of the interaction, ripe with controversies, among the network’s actors⁸. Note that, acknowledging these differences between LCA and ANT approaches, is actually pointing at some of the weaknesses of LCA.

4. To transform LCA into an ANT-compatible methodology, a number of steps would need to be taken. This is still under development and a detailed account does not belong here. However, an essential leap forward in the conceptual content of the methodology consists in taking on board non-human actants. See [8] for a more detailed analysis on that matter.

5. Giving examples of non-human actants that come up in trying to develop an ANT-compatible LCA, may help clarify what this new and difficult concept of non-human actors can mean: thus, CO₂ and Climate Change, the biosphere and the collapse of biodiversity, and she materials of which the object of the LCA, the Functional Unit (FU), is made, are all non-human actants. A longer list is given in a footnote⁹.

6. One important non-human actant is therefore the material (s) of which the FU is made. Steel, or aluminum or a polymer thus become actants in the analysis and also in the process of generating the FU – thus a real, not simply a meta-actant.

7. This is the major concept that we need to borrow from ANT to complement the analysis of materials started in this article. Materials are actants in the socio-technical networks to which they belong. In other words, materials have agency¹⁰ [14,15]. This kind of statement has been made before [16], but without referring to ANT and thus without the strength that this intellectual filiation imparts to it.

8. We posit further that what is true in the narrow network and the short time scale of an LCA, remains true in the longer time scale of developing new materials (the SCM scale) but also the much longer time of history, encompassing the multiple and continuing waves of successive developments, for example from Hittite iron to ArcelorMittal steel.

9. In other words, the continuity that we have observed, without proposing an explanation for it, is simply due to the fact that iron (metal, material) has exhibited agency all along historical time and is an actant per se, beyond the humans, the smelters and blacksmiths of ancient times, the steel producers of the 19th or 20th centuries or the owners of the mammoth steel companies of today. There is therefore no need to look for some properties of iron, that are enduring across long time and that would explain that perenniality – although it is fine to do it as well, but not necessary from a socio-dynamical standpoint. One could say, though, that materials, being part being part of networks of actants (for example, limiting, mediating, or facilitating the actions of other actants, both humans and non-humans), their roles and positions in the networks evolve as these networks evolve. As long as materials continue to be embedded into networks, they continue to exist and to exercise their agency. The announced analysis of LCA in connection with ANT should provide some insight into how this happens.

10. Once a material appears and is used to a significant extent as shown in Figure 2, it will carry on, more or less indefinitely – as the limited experience of 30 000 plus years of human history seems to demonstrate.

5 Wrap up and tentative conclusions

1. Materials have a synchronic (now) and a diachronic (then) time extension. The “now” belongs today to science and technology, but, before, it belonged to handicraft and more simply to simpler empirical knowledge. The “then” is a more reflexive recollection of the past as reconstructed by History or other social sciences (Anthropology, Paleo-Anthropology, etc.).

2. Materials are social constructs, which means that they have been noticed and used (materials are matter that is used) when society was in need of them. Iron from meteorites was collected as a curiosity millennia before iron was smelted. The book by Bruno Latour about Louis Pasteur [3] shows very clearly that he “invented” vaccines, not so much because he was a clever and creative person, but because he had already found out that the concept of microbe was becoming “necessary” in 19th century Europe, which was developing big cities, where contagious diseases were propagating at an alarming scale. The vaccine was a clever and sort of an obvious way to fight microbes. The same is true of materials, although the detailed and careful analyses à la Latour are not completely available.
   This concept implies that there is an equilibrium between society at a given point in time and the technology it has at its disposal – this includes materials. Or that technology does not drive society but rather the contrary. This questions the idea of progress¹¹, supposed to be driven by technology and more recently by science, and the assumption that technical progress led to social and even to political progress. In Ancient Times, it was clearly demonstrated that materials came after major social changes had taken place and therefore “called” for them. Today, this is also probably true, although the argument is not necessarily widely accepted, yet.

3. Structural materials form a continuous chain from ancient times until today. This continuity has been highlighted by Ashby, but is also obvious in the work of paleo-anthropologist Leroy Gourhan and it is intuitively accepted by metallurgists and materials scientists: continuity for metals, mainly iron, copper and the “seven metals”, for glass and ceramics, for stones and concrete, for composite materials, for textiles, etc. These materials have been changing over time in several parallel ways: increased purity, enhanced cleanliness, control of (micro-) structure, enlarged families of alloys, increased productivity of metalmaking reactors, higher energy efficiency, access to higher temperatures for metalmaking, reduced emissions to the environment. These changes, as explained before, are socially driven. There is a large literature documenting these evolutions that belongs to the history of technology and has been written by historians and engineers, who each look at it from slightly different angles.

4. These structural materials tend to endure for indefinite periods of time, of course since they were invented – a social construction event. This means that the competition among materials never led to any of them fully replacing another and annihilating it altogether. Of course, there is no doubt that lithic tools and weapons were replaced by metallic ones, and copper by bronze and bronze by iron. However, stones are still used today, for construction or for milling flour, copper and bronze also and the steel of Thyssen Krupp is quite different from Roman iron used in nails or the puddled iron of the Eiffel Tower, thus newer steel replacing older steel or iron. The materials change usage and functions, but the artifacts to which they contribute also changed to an even larger extent. Thus, what remains is a continuity of usage in changing societies. Copper is an interesting case in point, as it developed into a functional material, wherein its “most useful” property is presently electrical conductivity, used in connection with the universal use of electricity, nowadays¹² – but structural uses are still in play, such as in copper pans, roofing in Northern Europe, etc.

5. How materials change as a function of time is described by the analysis of the Social Cycle of Materials (SCM). Its characteristic time is different from and mostly longer than the life cycle of a product, a material, as it is a diachronic temporality that describes how innovation takes place – an analysis proposed by Wiebe Bijker¹³ prevails [17] but is also analyzed in STS and in ANT [11]. Bijker describes the process by which innovation takes place, in research labs today but in all of society as well, particularly yesterday when there was yet no science and no laboratories for conducting research. Like social scientists like to do, he shows that it is not a straightforward path (like an engineering project), but a kind of Brownian trajectory that goes up and down, forward and backward, until a closure is reached thanks to a network somewhat similar to an ANT network¹⁴. The characteristic time is a long time, although a shorter one than historical time.
   Note that analysis similar to SCM could be used to analyze how the use of structural materials have been changing with time.

6. The population of the periodic table by the 118 elements known today shows a kinetics of discovery of elements parallel, but not identical, to the discovery of materials¹⁵. Both elements and materials are social constructs and they were therefore invented when society needed them. Over the years, structural materials increased in numbers but mostly in complexity, metallurgists would say in “quality”. Thus, continuity exists in parallel with change: the property of being old and new, at the same time.
   The continuity is empirically demonstrated, but the reason for it is still unclear: why aren’t these materials been replaced, substituted by “new” materials, and why haven’t they simply vanished?

7. To reach beyond this tension, we proposed to call on ANT, a methodology developed by social science, when it wonders about how technical objects are constructed. The theory focuses on a network of actors, called actants, which comprise non-human actors beyond people, therefore living beings but also non-living ones. If one applies ANT to materials, then materials themselves become actants. And, in the theory, all actants, human and non-human, have symmetrical roles, which means that they all have agency – an ability to influence what happens, in effect an ability to act.
   Structural materials have thus been in continuous use for long historical times quite simply because they have agency.

8. This may look like a magical argument and it would probably be useful to go deeper in the analysis of why materials have agency. But we have to watch for circulatory arguments and not retreat to the enclosed spaces of STEM-only references.

9. We can now understand the title of the paper:

1. materials are social constructs, they are designed to answer the needs of society, hic et nunc, and “new” materials are invented and made available when society as a whole requires them.

2. however, because materials have agency, many of the new materials are evolutions of older ones. There is a kind of rigidity associated with these materials that endures through long time.

A companion paper [12] proposes a parallel effort to introduce ANT in connection with materials, but more specifically as a possible way to rethink LCA and SCM methodologies.

Note that ANT is being used in other fields of research than materials science. See examples in literary criticism, an area, which is often a pioneer in borrowing concepts and theories from adjacent fields of SSH, and thus in innovating [18,19].

The concept of agency has also been advanced in connection to materials in archeology and anthropology literature, although without the linkage to ANT [20,21] and without referring to materials in the exact same way as we do here. Van Oyen explains that “material objects have an effect on the course of action that is irreducible to direct human intervention”. Agency thus comes up as an emerging property of material objects in the discourse of social sciences. Kirchhoff refers to material cultures and spells out conditions for agency to become one of their features: “Material entities have, ontologically and epistemologically, the quality of agency” only if “all material entities are beings in the world alongside other beings, such as humans, plants, and animals” or/and if “all material entities have de facto existing qualities that affect and shape the way human beings perceive and understand the world.”

Acknowledgements

This work is the result of continuing discussions with two people: my wife Kathie Birat, who has been exploring how to use ANT and Latour’s ideas in literary criticism and Andrea Declich with whom I have been playing balls regarding social constructivism, STS, SCOT, and the ideas of Bijker and Latour for many years.

References

All Figures

	Fig. 1 Beating swords into ploughshares, a statue by Evgeniy Vuchetich at the United Nations in New York City. De l’épée à la charrue, une statue de Evgeniy Vuchetich aux Nations Unies dans la ville de New York.
In the text

Fig. 2 Discovery of elements along the historical timeline from year 0 to the 21st century. By 2020, all the elements in the table had been discovered (source: Periodic Table app, Royal Society of Chemistry, 2012). Découverte des éléments au cours de l’histoire, de l’année zéro au 21e siècle. En 2020, tous les éléments du tableau avaient été découverts (source : Periodic Table app, Royal Society of Chemistry, 2012).

In the text

	Fig. 2 (Continued)
In the text

	Fig. 3 The 52 elements used in a smart phone in 2021. Source: Ingénieurs sans frontières (CC BY-NC-SA). Les 52 éléments utilisés dans un téléphone de 2021. Source : Ingénieurs sans frontières (CC BY-NC-SA).
In the text

	Fig. 4 Continuity of materials across historical time spans. Continuité des matériaux sur des périodes historiques.
In the text