1 Introduction

One of the most important questions with regard to the problem of imagination, on the philosophical-epistemological level, is the ‘puzzle of imaginative use’: how can we distinguish between cases in which imagination is used to distance us from reality and those in which it allows us to learn more about the world? (Kind and Kung 2016; Williamson 2016; Langland-Hassan 2016, 2020; Spaulding 2016; Arcangeli 2013).

In the first section, after briefly illustrating this puzzle, I will refer to the use of imagination in science, highlighting, in particular, the problem of imaginative constraints: if the epistemic value of imaginative activity, especially in science, depends on constraints and limitations placed on imagination, it could be assumed that this epistemic value is not so much to be attributed to imagination per se, but rather to the constraints to which imagination is subjected (Stuart 2021a).

To solve this problem, in the second section I will propose examining imagination, understood as an ability, in the light of some recent discoveries in neuroscience (cf. Levy and Godfrey-Smith 2020), and more precisely in the light of the latest studies on Embodied Simulation. This will make it possible to accommodate the need to understand in what sense and for what reason placing constraints on the imagination makes it possible to acquire information about the real world.

The essential point of our proposal consists in understanding imagination as an embodied mental activity, which allows us to grasp in the imaginative act the nexus of creativity and method that is essential to the scientific enterprise. In particular, the use of thought experiments is based on the exercise of imagination to construct representations of the world and learn new aspects of reality (McAllister 2013). And even our ability, within the scientific enterprise, to imagine counterfactual situations can be explained by the activation of embodied simulation mechanisms which, as Gallese (2019) in particular has pointed out, consists of background knowledge linked to the body, which we acquire in our relationship with the world and use in our daily life, also when we imagine or tell stories. In short, the limits and constraints of imagination are the limits and constraints of an embodied imagination; it is precisely by clarifying the embodiment of imagination that we can recognize the epistemic role of imagination itself in science and rediscover the link between creativity and method, essential to the scientific enterprise. In science, it is inevitable that imaginative acts must translate into intersubjectively shareable procedural steps, and conceiving of imagination as a skill linked to embodied simulation mechanisms offers us the possibility of investigating the connection between the creative moment and technical methodicality in science, with reference to the role of the body (cf. in particular Fehige and Wiltsche 2013).

2 “The Puzzle of Imaginative Use” and the Problem of Imaginative Constraints in Science

There is an obvious difficulty among contemporary philosophers, to offer a substantive characterisation of imagination (Langland-Hassan 2020), as there is recognition of the ambiguity of a phenomenon that is difficult to label or encapsulate in an unambiguous definition.Footnote 1 At the same time, however, imagination is something we use every day of our lives in a boundless variety of ways: our minds develop and evaluate possible imaginary worlds that, in various cases, guide our practical choices and enrich our experience. From this point of view, imagination is a phenomenon with which we are very familiar, which we experience in different but related situations, such as make-believe games, daydreams, creative acts but also in counterfactual reasoning or in planning our routines.

The ambiguities of a phenomenon as complex as the imagination have given rise to a debate, which over the last ten years has developed around the problem known as ‘the puzzle of imaginative use’ (Kind and Kung 2016). What the mind’s eye sees or reconstructs, in fact, in some situations, distances us from reality, appealing to a freedom that seems to lack any constraint; in other situations, however, the imagination allows us to learn something new about the world, when, for example, through a type of counterfactual reasoning, we evaluate different possibilities not only to orient ourselves in the future, but also to reflect on our past choices. How is it possible, then, that the same faculty, ability, or state of mind is able to take us away from reality and at the same time bring us closer to it, to make it clearer and more accessible to our experience? Kind and Kung formulate the problem as follows:

Imagination is sometimes used to enable us to escape or look beyond the world as it is, as when we daydream or fantasize or pretend. We’ll call this the transcendent use of imagination. Yet imagination is also sometimes used to enable us to learn about the world as it is, as when we plan or make decisions or make predictions about the future. We’ll call this the instructive use of imagination. But how can a single mental activity successfully be put to both uses? How can the same mental activity that allows us to fly completely free of reality also teach us something about it? (Kind and Kung 2016 p. 1).

In the pars construens of their work, the authors propose making the instructive use compatible with the transcendent use of the imagination by discovering the constraints that root the imagination in the real world, thus giving direction to its expansive powers. Since a completely free imagination could not perform any instructive function, according to the authors it is not a matter of eliminating the tension between the two uses, but rather of taking this tension to identify the nature of those imaginative constraints, without which the very activity of imagination would not occur.

The authors, in particular, identify two classes of constraints:

First, the constraints may be architectural; that is, they may result from our cognitive psychological architecture. Our psychological architecture prevents us from imagining certain things or using the imagination in particular ways. Second, the constraints may derive from a non-architectural source, such as from our will. This latter class of constraints is of the sort that we can (perhaps only when properly disciplined) voluntarily impose upon our imaginative projects (Kind and Kung 2016, p. 21).

But not all constraints allow for an instructive use of the imagination. The central issue in the recent debate around the problem of imaginative use has thus become that of defining the nature and characteristics of those particular constraints that would allow the imagination to increase and improve our knowledge of reality.Footnote 2 Without such constraints, imagination would not act as a guide to inferences and actions, but would be an empty exercise of freedom devoid of any epistemic value.

This is particularly true for scientific discourse, in which the need to investigate the mechanisms that bind the imagination to reality emerges as consequential in order to clarify whether and how the imagination can acquire an epistemic value, not limited to the simple production of ideas free from any reference to reality. Particularly in recent years, the number of studies on creativity and the role of fiction in the work of scientists has increased considerably (Levy and Godfrey-Smith 2020; Langland-Hassan 2021; Murphy 2020; French and Murphy 2021; Casas-Roma et al. 2021; Stuart 2019, 2020, 2021a; b). To this must be added that, in order to investigate the mechanisms that anchor the imagination to reality, the synergy between cognitive science on the one hand and philosophy on the other has been of considerable importance.Footnote 3 Empirical methods have been used to study the use of imagination in the educational sciences or the use of thought experiments by students at different stages of learning (cf. Gilbert and Reiner 2000; Velentzas and Halkia 2013; Kosem and Özdemir 2014). An interesting study conducted by Michael Stuart (2019), for example, looked at the question of how and why scientists use imagination in their everyday work. From this study, based on interviews and direct observation of scientific practices, it emerged that imagination is exercised most when analysing specific problems in the context of mature science. When university students learn to solve specific problems they have to learn to apply certain methods, and imagination does not seem to be part of this process; things change when the teacher introduces more general problems by teaching the student to segregate subproblems. Again, the student is not encouraged to use imagination; however, it will manifestly take over when something does not go as expected, when the best methods fail. In short, scientists themselves seem to be aware of the role of imagination, but especially at a mature stage of science since one has much more background knowledge than the university student at that stage. And it is precisely this background knowledge that would allow the fruitful use of imagination (cf. Stuart 2019).

If we consider Stuart’s empirical investigation of scientific imagination in relation to the problem we are discussing, we can see that it argues in favour of the fact that imagination in science ‘works’ best—produces new ideas and advances the scientific enterprise—if it is bound by, or anchored in, prior background knowledge, through which an experiment is constructed.

Reflection on the role of imagination in science, in fact, often leads back to reflection on the epistemic role of the scientific thought experiment (cf. McAllister 2013), which, considering the nexus between real and thought experimentation,Footnote 4 can be defined “as an instance of the application of imagination to construct representations of the world” (McAllister 2013, p. 11).Footnote 5 In this sense, thought experiment presupposes the use of imagination as a means of learning about reality and imagination “is not a possible extension of observation, but a constitutive part of it” (McAllister 2013 p. 16). With Gooding, we can easily state that through thought experiment “scientists go from the actual to the possible, on to the impossible, and return to an actual world altered by that journey” (Gooding 1990, p. 204). But the return to reality is made possible by the constraints of an imagination that is only able to exert its creative force with and through those constraints; to think, however, of a ‘constrained’ creativity would seem a paradox. For this reason, it has become necessary, particularly in science, to reflect carefully on the constraints of scientific imagination, through which creativity is exercised, which cannot simply be a free exercise of the imagination, since in science every step leading to discovery must be reconstructible and traceable by the entire community of experts (cf. in particular Buzzoni 2004, 2005, 2009; Savojardo 2014). It is here then that background knowledge plays an essential role, since scientists, through real and thought experimentation, recognize themselves as sharing familiar approaches and procedures based on technical-operational interventions and thus, ultimately, on the body (cf. Fehige and Wiltsche 2013), always within a certain living space.

This conception of experimentation, thought and real, as a function of embodiment (Fehige and Wiltsche 2013) leads me to interrogate the field of cognitive sciences, in order to show in what terms the problem of imaginative constraints is addressed.Footnote 6

3 Creativity and Method in the Empirical Sciences: the Embodied Simulation Perspective

As mentioned in the previous section, we must now try to frame the idea of imagination as an embodied activity. For this purpose, after a brief presentation of the concept of Embodied Simulation, in this section I will present some reasons for conceiving the role of imagination as an activity based on sensory-motor schemes, activated by simulation mechanisms that exploit the potential of the brain-body system. This will allow me to approach the relationship between creativity and method, in science, from an embodied perspective.

The revolution of the ‘embodied’ mind, which took place between the 1980s and 1990s and was already anticipated in evolutionary psychology by Piaget’s (1968) and Vygotskij’s (1978) constructivism, is based on the idea that the cognitive system does not consist of a disembodied Cartesian mind whose role is essentially to manipulate symbols, but of a mind that is always connected not only to the physical and natural dimensions but also to the cultural and social dimensions of the world around it.

The general thesis of embodiment is understood here to mean that cognition is embodied because it is dependent upon the whole-body characteristics of an agent, which therefore play a significant, constitutive causal role in the agent’s cognitive processing.Footnote 7 This thesis can be found in Embodied Simulation Theory, developed by Vittorio Gallese (cf. especially Gallese 2009, 2011a, b, 2018a, b, 2019; Gallese and Sinigaglia 2011a, b), in relation to mirror neuron theory. The mind in this case realises cognitive processes to the extent that it is in a body that has always been embedded and acts in a social, cultural and linguistic context. The formation of the self appears to be intimately connected to the development of the mind through intersubjective processes of simulation that involve our sensory-motor system: “The brain level of description—Gallese writes—is necessary but not sufficient to study intersubjectivity and the human self, unless coupled with a full appreciation of the tight relationship the brain entertains with the body and the world” (Gallese 2018a, p. 31).

In order to understand the meaning of this statement it is necessary to start from the theory of mirror neurons, on which the Embodied Simulation perspective is based (cf. Matelli et al. 1986; Fogassi et al. 1992; Gallese et al. 1996; Rizzolatti et al. 1996, 2000; Gallese 2000, 2001). These studies, as is well known, suggest the presence in our species of a ‘mirror system’ similar to that initially discovered in the monkey, whereby every time we observe an action, not only are the visual areas of the brain activated, but so are a series of motor cortical circuits that are normally active when we perform those same actions. As Gallese writes: “Although we do not openly reproduce the actions we observe, our motor system is activated as if we were performing the actions we observe. In other words, the observation of the action implies the simulation itself” (Gallese 2001, p. 83, my translation). From this it can be inferred that the understanding of the other’s action, rather than through a visual description, occurs thanks to doing, to a shared bodily movement that creates an unbreakable bond between the observer and the observed. If in the observation of the action the same neurons of the corresponding movement are activated, one can speak of a system of simulation and in this sense “the representation of another’s action would be nothing more than the result of an extension to others of the capacity to model one’s own behaviour” (Gallese 2001, p. 88, my translation). This is an automatic simulation process that takes place by recruiting in off-line mode the same action and perception systems that are involved during the action and perception being performed (cf. Palmiero and Borsellino 2018; 2014). It has also been shown that the same cells are activated not only when the subject performs an action or observes someone else perform the action, but also when a noise is heard that is somehow related to that action (Kohler et. al 2002). Even some cells are activated when the interaction between subject and object is not fully visible (Umiltà et al. 2001). This would demonstrate the reaction of mirror neurons independently of the sensory modality that carries them. The discharges of mirror neurons, in this sense, also seem to reflect the meaning of the action, as if they somehow register its concept (cf. Palmiero and Borsellino 2018; 2014).

In short, the discovery of mirror neurons, as motor neurons, has led to interpreting the ability to understand others as intentional agents not in terms of propositional skills based on the manipulation of symbols through the use of formal syntactic rules, but primarily in terms of the relational nature of action. Action assumes a central role in intersubjective relations because it provides, “a direct, non-predictive, non-inferential simulation mechanism by which the observer is able to recognize and understand the behaviour of others"(Gallese 2001, p. 92, my translation; cf. also 2018a) through the activation of mirror neurons at a sub-personal level.

Here we find the central aspect of Embodied Simulation which is functional to the more general thesis of this paper. It lies in the idea that every mental representation has a bodily ‘format’ and that therefore every mental activity is to some extent subject to bodily constraints. Mirror neurons, as motor neurons, enable simulation activities, which occur in social, cultural and physical interaction with the world. In this sense, simulation can be considered the primary tool for understanding and conceptualising the world and intercorporality becomes the primary source of the relationship with the other. The body, understood as a ‘phenomenological body’ (Fehige and Wiltsche 2013) and not as an ‘object among others’ (in Husserlian terms, Leib), in its neural mechanisms of mirroring, bears traces of the encounter with the world. Sensory-motor simulations seem essential not only for perception but also for the formation of concepts (Barsalou et al. 2005). Language itself is embodied; one need only think of the role of affordances: sentences containing words that refer to actions or manipulable objects activate the motor system that corresponds to that very action (Martin 2007; Raposo et al. 2009).

Embodied simulation thus becomes the paradigm of a new conception of intersubjectivity and social cognition: every mental representation develops in the intersubjective relationship, through mirroring mechanisms that are activated at the brain level. At the basis of intersubjective relations there seems to be a common space that is formed through the activities of embodied simulation, which concern not only the perception of actions, but also the emotions or sensory experiences of the other. More importantly, as Gallese (2019, p. 16) points out, mirroring mechanisms also seem to be activated in remembering, planning for the future or listening to stories, areas in which imagination plays a central role. The common space that is constructed through the mechanisms of embodied simulation ends up delineating the boundaries of that background knowledge that we acquire in our relationship with the world and that constitutes the very condition for the development of Embodied Simulation (cf. in particular Gallese 2018a, 2019) and, thus, also for the use of imagination as an embodied skill.

Thinking that the mechanisms of embodied simulation, based on the activity of mirror neurons, also concern the use of imagination, as Gallese himself states (cf. Gallese 2019; Wojciehowski and Gallese 2011), will allow us to return to the problem of imaginative constraints in science from an embodied perspective, through which the relationship between creativity and method in the scientific enterprise will take on a new meaning.

As has already been pointed out, thanks to the discovery of mirror neurons, it can be argued that visual and motor imagery does not simply depend on propositional concepts or attitudes, but on the activation of sensory-motor regions of the brain, which enact embodied simulation processes in relation to other bodies acting, feeling or experiencing pain around us. The embodied approach has important consequences for the way we understand mental images (Foglia and O’Regan 2016), which are conceived in their bodily and motor interactions with the environment. Aspects that are easily found in our daily experience, and that concern our emotional and physical involvement in imagining certain situations that can test our emotionality as well as our bodily performance, are confirmed in experimental studies: heart rate and respiratory rate, for example, increase during the imagination of physical exercise (Decety et al. 1991). As Gallese himself pointed out, referring to recent neuroimaging studies,Footnote 8 from a neuroscientific point of view, there would be a very close link between the brain mechanisms of perceiving an action and imagining an action: “When viewed from a neuroscientific perspective, the border separating real and imaginary worlds appears much less sharp and clear than what humans thought for centuries. […] Thus, the neurobiological mechanisms enabling the connection to the ‘real world’ largely overlap with those connected to fictional world” (Gallese 2019, p. 117). Although at the reflexive level a world-embodied mind bases its activity on the clear distinction between the real and the imaginary, it is possible to argue that at the level of brain mechanisms we relate to and empathise with fictional images or characters in ways similar to how we relate to real subjects who inhabit our shared social universe (see especially Gallese 2019, 2018b, 2011a).

Understanding imagination as an embodied activity, based on neurobiological mechanisms that are functionally similar to those of perception, allows us to recognize Embodied Simulation as a system of understanding that at a sub-personal level depends on the activity of mirror neurons and is activated not only in the perception of actions or emotions, but also when we imagine possible scenarios of events or situations and when we construct counterfactual scenarios in thought and real experiments with scientific imagination.

Returning to the problem of imaginative constraints in the use of scientific imagination, we can then turn to the counterfactual-type assumptions that delineate a series of conditionals, linked to imagination, that are omnipresent in science (cf. especially Williamson 2016, 2020), as, in a more obvious and immediate way, in common thought. The human mind is also able to represent a perceptual datum as hypothetically excluding other possibilities that are not directly present to the senses: it is possible, for example, to perceive the red of a rose currently present to my senses, hypothetically assuming the possibility that it could be any other colour and then rejecting this possibility on the basis of the relationship between my eyes and the object; this possibility, understood as a general possibility, basically coincides with the capacity to formulate hypotheses and to use discursive reason.Footnote 9

As has been rightly noted, without this hypothetical capacity of the mind, which depends on our imaginative powers, our techniques for intervening in the world would be indistinguishable from the simple natural change of things. Our reasoning in a counterfactual manner through an imaginative capacity that is always oriented or constrained by the datum constitutes the condition of our interventions in the reality that surrounds us, periodically clarifying different cause-effect links in empirical reality. The same mental processes that we use in our daily lives are also found in scientific thought, albeit at a more elaborate and conscious cognitive level: without the construction of counterfactual scenarios, the scientist would be precluded from intervening in reality. Not unlike the historian, the natural scientist, in order to explain what happens, must also ask himself what might have happened in hypothetically different situations (cf. Buzzoni 2008, e.g. pp. 116–117).

However, imagination in science requires a specific analysis aimed primarily at the behaviour of scientists in their routine work. Studying imagination in science means asking how and in what situations the scientist is aware of his or her own ‘imaginative effort’, that is, of the fact that creativity and method constitute an inseparable link from an operational point of view (see in particular Buzzoni 2009). If, in fact, the philosophy of science starts from the direct observation of scientists’ work, an imagination will necessarily emerge that is always translated into a certain methodology; a totally free imagination in a field such as science would be neither conceivable nor ‘practicable’ and, as we have mentioned, would jeopardise the very value of science and experiment, because without the recognition of certain constraints we would never be able to reconstruct the procedural steps that led to scientific discovery (cf. in particular Buzzoni 2004, 2005, 2009; Savojardo 2014). Indeed, it should be clearly stated that there is no imaginative activity without constraints and that imaginative effort itself is made possible by an imagination that has always been constrained. This, however, does not mean denying the creative nature of imagination, but rather recognizing it with and through its constraints on a technical-operational level. Nothing in science is definitive, least of all views of the imagination as constrained and definitions of these constraints. While it is true that there is now a tendency towards exhaustiveness on the horizon of the current epistemology of imagination (Stuart 2020), my attempt to consider the use of scientific imagination from an embodied perspective is not intended to move in that direction. On the contrary, the imaginative constraints, considered with reference to the mechanisms of Embodied Simulation, are not enclosed in a rigid definition, but are identified in corporeality, in that interpersonal space in which my body takes on meaning in the unconscious, almost automatic experience of mirroring, with respect to a shared, but never definitive ‘semantic space’ (cf. Gallese 2018a). The creative urge, in art, as in science, makes its way into this shared space and corporeality can be understood as a means and a limit as it allows creativity to emerge in respect of a constrained context: creative experience always occurs through the innovative or alternative use of available resources, either in empirical reality or in principle, whether innate or acquired, and is realised in a shareable result (cf. Palmiero and Borsellino 2018, 2014).

From this point of view, the link that exists, on an empirical level, between creativity and method in the scientific enterprise, can be reworked through the language of neuroscience, in particular by referring to the mechanisms of Embodied Simualtion. The sharing of the space in which we are embodied binds our thinking and imagination, not simply in the sense of limiting what we can conceive with thought, but in the sense of providing conceptual and technical tools, through which our imagination can be translated into procedural steps that may be shared by the entire community. If we consider imagination as an ability linked to mechanisms of embodied simulation, such a translation will not only be essential but inevitable since we could never conceive of a mental activity separated, from a technical-operational point of view, from the body and from background knowledge that always assumes a corporeal ‘format’, since it develops in a relationship with the other that is not configured through propositional attitudes but through mechanisms of sensory-motor mirroring. It is thus finally understood why a completely free imagination would be devoid of epistemic value and not reconstructible at an intersubjective level.

The relationship between creativity and method in the scientific enterprise, from an embodied perspective, can be further exemplified by referring to the interpretation, from a phenomenological point of view, of the well-known thought experiment known as “Newton’s bucket” (cf. (Fehige and Wiltsche 2013), in which familiar objects and procedures are used to “show the existence of absolute space” (Brown 2011, p. 7). The “common word” (Robb 1921) that makes possible, using Gooding’s (1990) language, the transition from the real to the possible in thought experimentation, from the perspective of phenomenology, corresponds to the “domain of what we would like to call the possibilities of the lived body” (Fehige and Wiltsche 2013, p. 81). This domain of possibilities is closely connected with the notion of primordial space on which every concept of space is based; again, from a phenomenological point of view, the priority of the lived body is closely connected with the priority of a primordial space, without which no thought experiment on space would be comprehensible (Fehige and Wiltsche 2013, p. 81).

Now, this phenomenological view of the body, constantly open to the possibilities emerging around and through it, can easily be translated through the language of embodied cognition, in particular by referring to the mirroring mechanisms underlying Embodied Simulation. As we have observed, the activity of mirror neurons is connected to a simulation mechanism from which the subject’s responses in understanding the actions, emotions or sensations of others originate. These responses generate as it were a network of connections giving rise to that space of possibilities in which we also move and exercise our imagination, sometimes to escape from reality, and at other experiments, to penetrate it more times, as in thought deeply. We return here to the transcendent and instructive use of imagination (Kind and Kung 2016); we return once again to the thesis that imagination really has epistemic value only by virtue of its constraints.

As we have seen, neuroscience can offer us the tools to investigate such binding mechanisms. In particular, the latest studies on Embodied Simulation, have brought to light an imagination that is always embodied and linked to simulation mechanisms that bind it to an intersubjective space, delineated by intercorporeality.Footnote 10 In this sense, the link that emerges from a technical-operational point of view between the creative aspect and the methodical aspect of science has been reinterpreted: this link, in the context of our problem, becomes one between the capacity to imagine possible scenarios and the mechanisms of embodied simulation, which do not prevent the imagination from exercising its creative force but rather become the condition of its exercise in a relationship of interdependence with possible scenarios that are concretely realisable. It is not a question of limiting the imagination or putting a brake on the creative force without which science could not progress, but rather of proposing a vision of creativity, connected more and more to the human dimension, which is that of the biological subject, a subject that is a living body, inserted in a community, in an intersubjective dimension. If scientific creativity were not translated on a technical and shareable level, it would be an empty and useless exercise; but what matters, here, is to begin to recognize that such a translation passes through the mechanisms of a mind that has always been embodied, and this work intends to encourage further studies that go in this direction.

4 Conclusion

How can we learn about new aspects of the world through the use of imagination? What is the relationship between imagination and science? These are the two main questions addressed in this paper. As noted in the first section, the core of the debate around the problem of imaginative use consists in the need to define the nature and characteristics of certain constraints that would allow imagination to enhance our knowledge of reality.

Considering scientific imagination as constrained by mechanisms of embodied simulation, it can be concluded that it is not constraints that determine the epistemic value of imaginative activity in science, but rather imagination itself that possesses such value, being configured as an embodied ability that develops in intersubjective relations. From a neuroscientific point of view, the link between creative imagination and method in the scientific enterprise has thus been reinterpreted. The necessary technical-operational link between creativity and method in science is found in the imagination as an ability that develops through mechanisms of embodied simulation first generates and then exploits shared approaches and procedures, which contribute to the formation of an interpersonal space in which an encounter with the other and an understanding of reality takes place.

More precisely, the process of embodied simulation is generated in the brain by mirror neurons, motor neurons that are activated by the perception of an action, emotion or sensory stimulation of another who is being observed. However, recent studies allow for the assertion that similar simulation processes are also activated when we imagine perceiving something or performing an action, i.e. depicting a possible scenario with ‘our mind’s eye’. Thus, bearing in mind also the fact that, at the level of the brain the distinction between imaginary and real is not so clear-cut, we can recognize that the imagination also develops through mechanisms of embodied mirroring that make its creative exercise possible particularly, in science, through the use and design of thought experiments. From this point of view, the link between the creative aspect and the methodical aspect of science becomes one between the capacity to imagine possible scenarios and the mechanisms of embodied simulation which do not prevent the imagination from exercising its creative force, but rather become the condition of its exercise in a relationship of interdependence with possible scenarios that are concretely realisable.