Perspective Chapter: Affordance-Based Reverse Engineering of Natural Systems

Abstract

Affordance-based Reverse Systems Engineering (ARSE) focuses on the key enabling relationships between elements of a complex system (part-to-part affordances), and the enabling relationships between the system and its end users (end-user affordances). A novel application of this methodology to natural systems assists in a deeper understanding of the issues surrounding biological evolution, and the critical role of those precursor systems upon which it depends for success. ARSE represents an objective approach to these important questions since affordances simply delineate what actions the elements of a complex system, including the end user, can potentially take. Life-related systems are characterized by dependent sequences of affordances that are both spatially and chronologically nested across a broad spectrum of scientific disciplines. A reverse engineering approach that attends to all these sequences contributes to a more philosophically satisfying retrodiction in applying abductive reasoning to both the human condition and the cosmos as a whole.

1. Introduction

Can scientists, philosophers and engineers cooperate to gain insight into the mysteries of the human condition? Danish philosopher Søren Kierkegaard is purported to have said, “Life can only be understood backwards; but it must be lived forwards [1].”¹ Thus is summarized the great challenge of the human condition: To apply the present knowledge of our existence in deciphering the mysteries of our past (retrodiction) in order that we might proceed wisely into our future. The issues that swirl around the riddle of human origins deserve careful consideration, since the question of how we proceed is not uncoupled from the question of how we came about. These questions are big enough to enlist the services of multiple academic disciplines, especially the sciences, and the humanities, but also engineering.

The sciences are fundamental to our understanding of physical reality. And the humanities lie at the heart of comprehending human existence. But the practitioners of these approaches to truth-seeking have found it challenging to work together in addressing such big questions [2]. However, engineers find themselves in the unenviable position to serve as natural mediators between the sciences and the humanities. Engineering is concerned with applying the discoveries of science to address the needs and desires of the human population. This may normally involve the (forward) engineering design of some practical widget. But we propose that engineers have a further role to play by addressing some of these bigger questions, especially when it comes to implementing the concept of reverse engineering.

Reverse engineering has been defined as “the process for discovering the fundamental principles that underlie and enable a device… or system through the systematic analysis of its structure and, if possible, its function and operation. Usually, it involves taking the aforementioned apart and analyzing its makeup and workings… part by part… until the entire entity has been analyzed and is understood [3].” Reverse engineering is most often applied to gain understanding of artificial (humanly engineered) systems. But for many years now the biological sciences have had great success when bringing a reverse engineering approach to bear on living systems. Biologist E. O. Wilson claimed that “the surest way to grasp complexity in the brain, as in any other biological system, is to think of it as an engineering problem… Researchers in biomechanics have discovered time and again that organic structures evolved by natural selection conform to high levels of efficiency when judged by engineering criteria [4].”

As evolutionary biology has matured, a fresh appreciation for more complex environmental interactions has emerged. A new Extended Evolutionary Synthesis (EES) has been developed to account for the effects of niche construction, epigenetics, and “large-scale reengineering of the genome in response to environmental stimuli,” in addition to a number of other influences [5]. This renewed focus on interactions between the organism and its environment naturally leads to the concept of (end-user) affordances, defined as the organism’s enabling (or disabling) relationships with various aspects of the environment.

The authors submit this work as a continuation of an ongoing effort to synthesize discoveries and approaches from multiple disciplines that bear on the big questions associated with the human condition. We strive to objectively apply a reverse systems engineering approach with a focus on affordances, as described below. While a completely objective approach may be impossible to attain, we attempt to recognize our prejudices (i.e., monotheism) and eliminate irrational bias as much as possible.

2. Reverse systems engineering with a focus on affordances

Gestalt psychologist Kurt Koffka first suggested the usefulness of affordances in the early twentieth century. He asserted that humans perceive affordances in nature, culminating in the idea that things “tell us what to do with them.” He continued, “Each thing says what it is…a fruit says ‘Eat me’; water says ‘Drink me’; Thunder says ‘Fear me’; and woman says ‘Love me’ [6].” Though Koffka’s litany possesses a certain romantic flair, a more egalitarian perspective recognizes the preeminence of this most powerful of human affordances to all people; As the ancient Jewish proverb says, “What a person desires is unfailing love [7].”

But it was psychologist James Gibson who sharply advanced this concept by applying it to the field of ecological psychology in his seminal work, “The Theory of Affordances [8].” He claimed that affordances can be positive (enabling) or negative (disabling) and that they might be hidden from the senses. As in Koffka’s example, a body of water affords the quenching of thirst (hydration), as well as swimming, but it also affords drowning! especially in the case of a hidden undertow that sometimes occurs at the beach. More recent researchers have explored the connections between affordances and niche construction [9]. emphasizing the idea that “affordances are not mere action possibilities but that they can also invite behavior [10].”

Don Norman, with degrees in both psychology and engineering, introduced the concept of affordances to the field of engineering with his book The Design of Everyday Things. In an engineering context, he clarified that “An affordance is a relationship between the properties of an object and the capabilities of the agent that determine just how the object could possibly be used;” adding that “Affordances provide strong clues to the operation of things [11].” His reference to affordances as “clues” provides an early indication of their value for reverse engineering. Another early adopter of this idea was computer scientist William Gaver who asserted, “Affordances should be useful in exploring the psychological claims inherent in artifacts and the rationale of designs [12].” He further explored the idea of hidden affordances in more complex systems, introducing the concept of “sequential affordances…to refer to situations in which acting on a perceptible affordance leads to information indicating new [previously hidden] affordances.” He continued, “Sequential affordances explain how affordances can be revealed over time; nested affordances describe affordances that are grouped in space…The role of a good interface [between engineered system and end-user] is to guide attention via well-designed groups of sequential and nested affordances [13].” The identification of these different types of interdependent affordances is vitally important when conducting reverse systems engineering on complex systems consisting of multiple interacting subsystems.

But the engineering researcher who has most thoroughly explored the potential of affordances for assisting with both engineering design and reverse engineering is undoubtedly Jonathan Maier. He refers to affordance-based design as a “relational theory for design” since it helps to “explain the entanglement between designers, users, and [engineered] artifacts [14].² He has also proposed “an affordance-based method for reverse engineering and redesign [15].” This approach involves the careful analysis of an existing system “to see how it works and could possibly be improved [16].” Maier contends that after identifying and evaluating the affordances at every level, a system has been effectively reverse engineered in the sense that its operation should be well understood [17]. The reason affordances are so enlightening is because they exhibit complementarity. That is, they are relational in a way that illuminates how two things fit together in allowing for a potential outcome, be it positive or negative [18]. But the emergence of a particular affordance does not necessarily imply that the outcome is enabled to a high degree. Thus, affordances also exhibit quality, which describes how well the system affords a particular outcome [18].

Maier refers to the triad of (1) engineer, (2) engineered system, and (3) end-user of the system as the “big picture” of engineering design. He claims that a careful consideration of the relationships between all three entities is important for successful engineering design, and affordances help to capture these interactions [19]. In extending this approach to reverse engineering, the authors have introduced a fourth component to fully capture all six of the important interactions within the big picture of reverse engineering (see the double arrows in Figure 1, adapted from ref. [20]). This fourth entity is the investigator of the existing engineered system, or the “reverse engineer.” Several examples that help to clarify this approach are described in the first author’s recent book, Hacking the Cosmos [21]. A classic example from the twentieth century is the reverse engineering of the Antikythera Mechanism, delightfully recounted by Jo Marchant in her book, Decoding the Heavens [22]. From this account, we learn that reverse engineering projects draw, not only from the sciences, but also from history, culture, philosophy and any other pertinent knowledge base. This will prove true for natural systems as well. In the case of the Antikythera Mechanism, the engineered system was (it is no longer intact) an ancient, but highly advanced astrolabe, parts of which were recovered from a shipwreck off the coast of the Greek island of Antikythera in 1900 CE. The designer is the person (or persons) who devised and built the mechanism around 100 BCE. The end-user was the person (or persons) for whom it was originally engineered; those who operated the mechanism in the years after it was built; presumably for educational purposes, or perhaps as a status-symbol. And the investigator (or reverse engineer) is the group of scientists and engineers who spent the better part of the twentieth century attempting to unravel the mysteries of this most captivating device. As one can imagine, attending to the relationships between these four entities, which leads to several interesting affordances, has the potential to lend great insight into any reverse engineering project.

Figure 1.

The “Big Picture” of reverse engineering involves six relationships.

When dealing with more complex systems, a useful analysis tool for “concept exploration and attention directing” has been developed, known as the Affordance Structure Matrix (ASM) [23]. This instrument lists the system components across the top of the array (columns) and the resulting affordances along the side (rows). Populated elements of the array indicate which system components interact to produce end-user and part-to-part affordances. Both positive and negative affordances are included to assist in either engineering design or reverse engineering and redesign. In either case, the goal is to choose and arrange system components to maximize the number and quality of positive affordances and minimize the number and liability of negative affordances. Minor modifications have sought to improve the effectiveness of this two-dimensional layout by applying relative weightings to the affordances [24, 25]. Many examples of ASMs can be found in the references [14, 15, 16, 17, 18, 19]. In addition, a flowchart has been developed to illustrate a step-by-step procedure for conducting affordance-based reverse engineering (see Figure 2, adapted from ref. [20]). Affordances are identified as component interactions are analyzed at the system and subsystem levels. An affordance structure matrix is very helpful in this process. Now let us consider the application of this approach to gain a deeper understanding of natural systems.

Figure 2.

Flowchart for affordance-based reverse engineering.

3. Application of ARSE to natural systems

3.1 Justification and a comprehensible Cosmos

Reverse engineering is rightly applied to artificial, or human-made systems. But one might doubt the legitimacy of applying this approach to natural systems, even in the face of reverse engineering’s recent successes in biology. It may seem “unnatural” to think and speak in teleological terms when analyzing living organisms, much less inanimate objects such as water and rocks. But recent work in the philosophy of science suggests otherwise. Gunnar Babcock argues for the legitimacy of speaking in teleological terms of inanimate objects if we see that their function comes from a larger goal [26]. He makes use of McShea’s field theoretic account of teleology which states that external fields are responsible for the teleology of a system. These fields direct the entities within them persistently and plastically. Persistence refers to the tendency of a system that is following a certain pattern to keep repeating that pattern, while plasticity is the propensity of a system to choose a specific trajectory from several different starting points.

For example, if we put a ball in a bowl, it will always tend to fall toward the center because of the action of gravity. Even if the ball itself has no internal program that forces it to move to the center, we can still talk about its teleology if we consider that it has functionality as part of the system of gravity and that it still deviates slightly from its course depending on its starting point. All objects can have some level of teleology, and the higher their degree of persistence and plasticity, the higher their teleology. Hurricanes exhibit these characteristics since they generally appear in the same region but will change course according to atmospheric conditions. As another example, we observe a kind of natural selection in eroding rocks, since harder rocks survive over softer rocks during erosion processes. Geologists hypothesize that mineral species over Earth’s history have evolved with the changing environment. Various higher-level fields of temperature, pressure and biological interactions are responsible for the great variety of minerals we have today [26].

But how can humans even make sense of nature? We take for granted our unique ability to unravel the deep mysteries of the cosmos. Multiple advantageous circumstances have contributed to our technological understanding and advancement. Firstly, although natural systems are often incredibly complex, they exhibit extensive repeatability and generally follow orderly laws. In addition, the ordering of matter and energy, and the laws of nature are readily and accurately described by abstract entities and operations known as mathematics, which are somehow apprehended by the minds of scientists and engineers. Furthermore, human beings appear to be particularly well-suited and often highly motivated to decipher the secrets of the universe. They are especially successful in this pursuit when they make good use of all the tools at their disposal, and their efforts are remarkably profitable for humanity [20]. Indeed, the Earth, and all of nature, seems to be laid out in such a way as to facilitate scientific discovery [27, 28]. Albert Einstein recognized the significance of this match between human mental capacity and cosmic complexity (a prerequisite for reverse engineering) when he famously remarked that the most incomprehensible thing about the world is that it is comprehensible [29].³

The development of powerful microscopes has assisted in reverse engineering on the smallest scales. The chemical elements of our Periodic Table now provide the building blocks (like Lego blocks) and part-to-part affordances for the flourishing of nanotechnology. Biochemist Michael Denton alludes to the similarity between atoms and Legos as he writes, “The total number and diversity of possible chemical structures that may be constructed out of carbon, oxygen, hydrogen, and nitrogen is virtually unlimited. Almost any imaginable chemical shape and chemical property can be derived. Together these elements form what is in effect a universal chemical constructor kit [30].” Furthermore, the semi-permanent combinability of these elements appears to be absolutely reliable. We can count on certain reactions to always take place under a given set of conditions. This order and reliability at the foundation of the material world is actually a very remarkable feature of the cosmos, which was not fully recognized until the field of chemistry had sufficiently matured. Cosmologist Helge Kragh describes the impact this discovery had on the great scientist James Clerk Maxwell: “He [Maxwell] was impressed by the fact, as revealed by the spectroscope, that molecules of the same chemical species were all alike and had not changed the slightest ‘since the time when Nature began.’ Uniformity in time as well as uniformity one-to-another strongly indicated that atoms and molecules were created… Borrowing an expression from John Herschel, he famously (and with an allusion to natural theology) referred to the molecule as a ‘manufactured article’ [31].”

Philosopher Richard Swinburne points out that “any theory that at a beginning or always there were many substances, which fall into kinds with identical powers and liabilities, is again a theory of a very improbable coincidence.” He continues, “Such a coincidence cries out for explanation in terms of some single common source with the power to produce it. Just as we would seek to explain all the coins of the realm having an identical pattern in terms of their origin from a common mould, or all of many pictures having a common style in terms of their being painted by the same painter, so we should seek to explain all physical objects having the same powers in terms of their deriving them from a common source [32].” With these and other arguments, Swinburne attempts to mathematically quantify the question of God’s existence based on the natural world, and concludes that it is at least as likely as not. Quite simply, the universe appears to be the work of some kind of cosmic engineer (or engineers), as incredible as that sounds. Like the proverbial onion, the events of our expanding cosmos portray layer upon layer of nested affordances that ultimately lead to planet Earth and the life that so curiously flourishes upon it. Given the connection between affordances and engineering,⁴ it seems warranted to take an affordance-based reverse engineering approach to understanding natural systems. Such an approach may only be an exploratory hypothesis to be evaluated based on the success it engenders. But the authors consider that the tentative application of ARSE across the entire realm of nature seems justified by the evidence up to this point.⁵

3.2 Objectivity and the affordances that enable evolution

Maier argues that affordances represent an objective approach to understanding natural systems since they simply describe what can occur within such a system and what actions an end-user can potentially take. This leads to a common terminology and mutual understanding by people with very different worldviews. He writes, “[In reverse engineering of biological systems,] the function/purpose of any system is inherently subjectively defined. For example, while an evolutionist may not say that the function of a brain is to think,⁶ while a creationist would certainly say that it is, they could both agree to the fact that brains afford thinking [34].” Philosopher John Sanders agrees with Maier and argues further for the foundational nature of affordances. He claims that affordances “offer a conceptual tool of exceptional value in the construction of a positive theory of embodied agency [i.e., humanity], and of its philosophical consequences [35].” He asserts that affordances “deserve to be given a leading role in…first philosophy [36].⁷ “Why should affordances enjoy such a prominent place in understanding reality? Sanders writes, “while ontology [the study of being] must be relativized to what different observers can do in terms of affordances, this is no mere matter of what the observer thinks or believes. It is a function of what the observer can do, and this may be as objective a matter as anyone could hope [37].” In short, an affordance relationship simply results in an undeniable enablement that is independent of various philosophies or beliefs involving function or purpose.

But even if a single affordance is free of teleological baggage, the picture is not as clear when groups of affordances are found in nested layers that appear to ingeniously provide opportunities of great value, such as human life and love. Could these kinds of affordance structures be signs of a deeper reality? In thinking specifically about human perception of affordances as signs, psychologist John Pickering writes that, “The characteristic reflexivity of human cognition means that we are not only able to perceive the world as it is,…but also to perceive affordances that do not yet exist, that is, to perceive the world as if it were otherwise…and hence we may take meaningful, intentional action to bring it about if we so choose.” He adds that, “nature is a harmonious sign system,” implying that affordances are signs that are indicative of meaning and purpose in the world. Thus, affordances appear to be critically important for studying “the interactions of animals, plants and their surroundings [which] are the concern of biosemiotics, the study of natural signs [38].” Renowned physicist George Ellis takes a similar perspective as he recently proposed the introduction of “possibility spaces” into the sciences. He writes, “I claim that the deep structure of the universe is timeless, eternal possibility spaces of a Platonic nature. These underlie the nature of what is possible in the physical universe and what is not… These are a way of re-expressing the nature of the laws of physics in terms of a space of possible physical outcomes [39].” In other words, his possibility spaces represent what can be in the universe and what agents can think and do in the universe, which arise directly from part-to-part and end-user affordances.

When seen in the light of nested affordances, the success of biological evolution depends on a long and complex series of dependent precursor relationships, both internal and external to living organisms. Biologist Christian de Duve said it well: “[Evolution] did not operate in a vacuum. It operated in a universe governed by orderly laws and made of matter endowed with specific properties. These laws and properties are the constraints that shape the evolutionary roulette and restrict the numbers that can turn up [40].” His reference to laws and properties could be stated more generally in terms of affordances that determine what is biologically possible in the universe. In considering the preconditions for biological evolution, a helpful resource is Philosopher Rope Kojonen’s recent book, The Compatibility of Evolution and Design. Kojonen evaluates reasons for the common assumption that evolution and design are competing explanations, and develops an alternate view. In the fourth chapter (Not by Selection Alone: Evolutionary Explanations and Their Requirements) he explores the intriguing aspects of nature upon which evolution depends. In reference to an entire evolutionary pathway, he writes, “…it is not clear whether the direction taken by the evolutionary series as a whole is impacted by other factors beyond those that we can discern in an isolated evolutionary event. The possibility of accumulating these mutations and forming new forms of life might still require other factors, such as the existence of an environment that supports the existence of this kind of form, the existence of natural selection, and the existence of a functional series of intermediate steps that connect functional forms. If such preconditions play a substantial role in making evolution possible, then this also needs to be taken into account in constructing the picture of evolution as a whole, and how it relates to design arguments. Supposing that these preconditions are the result of design, then it would no longer be true that evolution proceeds without design [41].”

But is there evidence to suggest that these preconditions are the result of design? Kojonen lays out affirmative reasoning, but biology is complex and only a few of his arguments are briefly summarized here. Regarding recent work to develop genetic algorithms (computer programs) to simulate the creative ability of evolution, he writes, “…it does seem credible to conclude that in genetic algorithms, the production of new information does depend on the existence of prior information in the system, and that such algorithms can only solve problems that they are specifically designed to solve. The systems must be built to reward stepwise growth, and the selective conditions must be adapted to the problem being solved. Thus, in these simulations, the possibility of evolution depends on design, demonstrating that there is no necessary contradiction. One can further argue that due to the strong dependency of the algorithm on design, the products of the simulated evolutionary process are revelatory of the intelligence of the programmer [42].” Some biologists, such as Denton, have adopted a “structuralist” view of evolution in which biological forms are the consequence of the laws of physics and chemistry, merely discovered by evolution. Such “laws of form” describe how relationships between elementary forms might ultimately afford more complex forms, as addressed by Kojonen: “In order for evolution to be possible, viable forms must be close enough to each other in the space of possible forms, and must form a network that can be navigated by evolutionary search. The study of protein evolution and convergence, among other factors, provides evidence that the course of evolution is directed by the structure of the space of forms, as well as laws of form, arising as a consequence of the laws of physics. Also, it may be that evolutionary biology could be understood as even hospitable to teleological interpretation, once all elements of the extended synthesis are considered fully [43].”

To be sure, the extended evolutionary synthesis more fully recognizes the key impact of relational interactions between organisms and environments (end-user affordances), and appears to more fully appreciate the pre-existing relationships that led up to and nurtured evolutionary processes (sequential and nested part-to-part affordances). The term “fine-tuned” has become popular in referencing the universe’s apparent fitness for life, but the authors believe a more accurate term is “engineered.” Indeed, the fact that natural systems are so readily and profitably reverse engineered by humans strongly suggests that these systems were engineered in the first place [44]. The connectedness of everything in the universe (heavily laden with affordances [45]) is aptly described in the following quote by the famous naturalist, John Muir, “When we try to pick out anything by itself, we find it hitched to everything else [46].” As part of his conclusion to chapter four, Kojonen writes, “The more our understanding of evolution has progressed, the more we find ourselves explaining patterns in evolution by reference to general principles, rather than just contingent historical events (which continue to have a great role in all models). Instead of explaining the appearance of purpose in biology by reference to non-teleological factors, the attempt at explaining design by evolution has succeeded in finding new layers of teleology. The further we study, the more the universe seems to be filled with teleology ‘all the way down!’ [47]”. The authors contend that an understanding of natural affordances, with the methodology introduced in this paper, helps to clarify our conception of the natural world, and assists in the formulation of a philosophically satisfying worldview. This approach is illustrated further in the following example involving life on planet Earth.

3.3 Example: A planet teaming with life

As expressed in the introductory section, we ultimately want to gain a better understanding of the origin and fundamental nature of human beings. Perhaps the knowledge gained will afford us the ability to act with more wisdom in the future. This goal suggests that humans be chosen as the natural system of study in this example application of ARSE. But as stressed above, human evolution cannot be effectively studied in isolation from the surrounding Earth environment, including all other living organisms. Indeed, we now know that the development of life on earth depended on the part-to-part affordances inherent in the processes of stellar evolution and the early expansion of the universe.⁸ Thus, a more comprehensive approach might choose the entire cosmos as the natural system of study. Though a bit excessive for this paper, it is the topic of the first author’s recent book, Hacking the Cosmos. Thus, the authors have settled on planet Earth and its life forms (focusing on humans in particular) as the natural system of study for this example.⁹

Even so, it is very challenging to apply ARSE to something as massive and complex as planet Earth and all its inhabitants. But the advantage of reverse systems engineering is the ability to break things down into subsystems and subsequently smaller modules. This will certainly be necessary as we proceed with this example, but to clarify the playing field at the outset, the place to start is with the big picture of reverse engineering shown previously in Figure 1. And a good place to start in the big picture is with the engineered system: planet Earth and the life it supports. In thinking about the designer (or original engineer) of this system, an atheist might choose to leave this spot vacant, while a theist would be comfortable with a supernatural deity (or deities) of some kind. Because it aligns with the beliefs of a large segment of the population and leads to some interesting philosophical considerations, for this example, we will hypothesize a Maker¹⁰ consistent with the traditional (Abrahamic) monotheistic religions. In filling the role of end-user, we are tempted by our anthropocentrism to insert ourselves. But we must remember that we are not the only inhabitants that enjoy the affordances associated with life on Earth. And it appears that all the participants in the web of life are important for life to flourish. Furthermore, a Maker of the aforementioned tradition is believed to have made all things for divine purposes. So for theists, there is a sense in which the Maker is not only the designer, but the ultimate end-user. This brings us to the final player in the reverse engineering quartet: the investigator (or reverse engineer). In this case, the reverse engineer is anyone who is curious and sincere enough to honestly delve into the deep mysteries surrounding how and why life is thriving on planet Earth. From where did life come? How did it originate and progress? How do we explain the extreme positives and negatives of the human condition? And is there a deeper meaning and purpose to life that should guide our actions?

A few general words should also be offered regarding the relationships between the four entities that make up the big picture of reverse engineering. While the designer of an engineered system would typically have in-depth and complete knowledge of the system, the end-user might only possess operational knowledge of the system; enough to use it effectively (or perhaps misuse it), without understanding every technical detail. However, an active relationship between the user and designer, including information exchange about the system, should lead to more effective and successful use of the system. The same is true for the reverse engineer, who would certainly seek out information exchange with the designer (if possible), or any documentation the designer might offer regarding the system. But the curiosity of the reverse engineer would typically take them deeper than operational knowledge of the system. This deeper knowledge could also be passed back to users to enhance their experience of the system. In the case of our living planet, scientists and other educators admirably perform this role. In considering the human condition on Earth, one of the most puzzling paradoxes is the great potential and hope users typically sense for a happy and successful life, which is so often met with commonly experienced negatives such as confusion, disappointment, disease, personal failure, and despair.¹¹ This state of affairs serves to lead some users into the role of reverse engineer as they strive to enhance their understanding of reality. Users/reverse engineers should also consider the possibility that this need for additional information (beyond that which is inherent to the system) might be made available in a different kind of knowledge format. Indeed, it makes sense that a good Cosmic Engineer (if one exists) would provide such additional communication to users if needed. This kind of helpful knowledge might come in the form of divine revelations, sacred writings, or incarnations.¹²

The next step in the ARSE methodology is the systematic identification of affordances by literal and/or figurative dissection of the system. After identifying the Earth as the system (following the flowchart in Figure 2), important subsystems are defined. We know that the Earth is a dynamic combination of interacting subsystems that have been changing over long time periods. Thus, layers of nested and sequential affordances are identified as (enabling or disabling) relationships occurring over both space and time. The simplest initial decomposition breaks the “Earth system” into four major spheres (hydrosphere, atmosphere, geosphere, and biosphere). However, “the interactions among Earth’s four spheres are incalculably complex [48].”

Even so, fundamental affordances are recognized in the relationship between the hydrosphere and the biosphere: for example, living organisms experience life-sustaining hydration. Similarly, the atmosphere affords life-sustaining aeration to the biosphere, as well as the mitigation of potentially life-threatening solar radiation and protection from the harsh cold of space. Through the action of gravity, the large mass of the geosphere affords a dwelling place for the other three spheres, which allows for their close interaction in space. For example, hydration is further enabled by the global water cycle, in which close interaction and exchange occur between the hydrosphere, atmosphere and geosphere, with obvious benefit to the biosphere. But along with the rain comes the potential for flooding in the valleys and dangerous debris flows in the mountains, with obvious disabling influences. Thus, negative affordances such as inundation and drowning are also recognized. Many more affordances could be identified, especially as the four Earth spheres are further broken down into additional subsystems. In addition, the sun, moon, and nearby planets exact their influences on the Earth and its inhabitants, illuminating even more affordances…But space is limited, so our discussion thus far will have to suffice.

A simple Affordance Structure Matrix (See Figure 3, adapted from ref. [20]) helps to illustrate how some of the subsystems and components interact resulting in affordances, but it is obviously far from exhaustive. In this ASM, the biosphere has been further subdivided into plants, animals, and humans. These, as well as a few other important components of the system, are shown across the top of the matrix. Significant end-user (EUA) and part-to-part (PPA) affordances are listed down the left side. The filling of the matrix then indicates which components contribute to which affordances. For example, the water cycle results from interactions among the four Earth spheres and the sun. Although life is listed as a positive end user affordance, it is also the result of many layers of a myriad of sequential and nested part-to-part affordances, hence the contributions from all system elements. This type of high-density affordance structure is characteristic of engineered systems.

Figure 3.

Simple affordance structure matrix (ASM) for life on earth. EUA: end-user affordance; and PPA: part-to-part affordance.

Though a helpful indicator of component participation (see totals to the right), the ASM is not a very effective tool for representing the sequential and nested hierarchical dependencies of affordance structures. Perhaps a more helpful representation is the dependency graph, which is used extensively in the development and reverse engineering of computer software and systems. A dependency graph simply shows the directional dependencies of several objects toward each other. Software engineer Winston Ewert has proposed the dependency graph as a new hypothesis to explain the nested hierarchical patterns associated with living organisms. He conducted an extensive quantitative analysis and concluded that “The biological data was a better fit to a dependency graph than to a tree [structure] [49],¹³ ultimately suggesting that DNA was constructed by a process similar to the automated compiling of a computer code [50].

On a larger scale, a simple dependency graph has been developed to illustrate the dynamic structures related to the evolution of the cosmos and living organisms from the origin of the universe (see Figure 4). Only the main pathways are shown, and many details have obviously been omitted for space and clarity, but it demonstrates the numerous layers of sequential and nested affordances that underlie planet Earth and its inhabitants. The emergence of a complex life form that can not only perform marvelous engineering feats, but also look back and marvel at the ingenuity with which they were engineered, is certainly a very curious development. Indeed, the whole realm of nature provides inspiration for humans engaged in the practice of engineering, as is evident from the biomimicry revolution [51]. Gaining knowledge and wisdom from nature is the key idea of biomimetics, both to better care for the Earth, and to better understand our own nature as humans.

Figure 4.

Simple dependency graph for earth and its life forms.

4. Summary and conclusion

Incorporating the concept of affordance (and extending it to include part-to-part interactions) into reverse systems engineering has led to a novel methodology of exploration, which has been fruitfully applied to enhance our understanding of both natural and artificial systems. While individual affordances objectively describe what can occur in a system, multiple layers of sequential and nested positive affordances are indicative of function and purpose. Investigating all the relationships in the big picture of reverse engineering and considering the pertinent evidence from all knowledge bases is especially important. ARSE appears to be an effective methodology for hacking the planet and advancing our understanding of the human condition. However, this approach is only as good as the models that are developed to represent reality. Thus, the ARSE methodology is limited by the difficulty of capturing all the important relationships along with their associated consequences.

The system of life on planet Earth offers an intriguing example in abductive reasoning. The emergence and development of living organisms depends on long strings of sequential and nested affordances that point to some kind of Cosmic Engineer, even in the face of significant evidence for biological evolution. Indeed, the very preconditions on which the evolutionary paradigm depends for success seem to have been engineered to ensure that success. In this sense, evolution and design appear to be quite compatible, as Kojonen suggests. Even so, the substantial negatives of the human condition offer a sobering check to this idea. But in light of the hope that we somehow persist beyond the grave, perhaps these negatives form a necessary part of the system; one that affords real freedom to complex organisms, training in the ability to fully love, and the apprehension of vital truths; truths that become ever clearer as we continue the quest of hacking the cosmos! [52].

Acknowledgments

I am grateful to all the students and faculty at Oral Roberts University who assisted me in this research over the last several years.

Conflict of interest

The authors declare no conflict of interest.