Cyber-physical Systems. Pedro H. J. Nardelli
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In the same year that Shannon published A Mathematical Theory of Communication, another well‐recognized researcher – Norbert Wiener – published a book entitled Cybernetics: Or Control and Communication in the Animal and the Machine [6]. This book introduces the term cybernetics in reference to self‐regulating mechanisms. In his erudite writing, Wiener philosophically discussed several recent developments of control theory, as well as preliminary thoughts on information theory. He presented astonishing scientific‐grounded arguments to draw parallels between human‐constructed self‐regulating machines, on the one side, and animals, humans, social, and biological processes, on the other side. Here, I would like to quote the book From Newspeak to Cyberspeak [7]:
Cybernetics is an unusual historical phenomenon. It is not a traditional scientific discipline, a specific engineering technique, or a philosophical doctrine, although it combines many elements of science, engineering, and philosophy. As presented in Norbert Wiener's classic 1948 book Cybernetics, or Control and Communication in the Animal and the Machine, cybernetics comprises an assortment of analogies between humans and self‐regulating machines: human behavior is compared to the operation of a servomechanism; human communication is likened to the transmission of signals over telephone lines; the human brain is compared to computer hardware and the human mind to software; order is identified with life, certainty, and information; disorder is linked to death, uncertainty, and entropy. Cyberneticians view control as a form of communication, and communication as a form of control: both are characterized by purposeful action‐based on information exchange via feedback loops. Cybernetics unifies diverse mathematical models, explanatory frameworks, and appealing metaphors from various disciplines by means of a common language that I call cyberspeak. This language combines concepts from physiology (homeostasis and reflex), psychology (behavior and goal), control engineering (control and feedback), thermodynamics (entropy and order), and communication engineering (information, signal, and noise) and generalizes each of them to be equally applicable to living organisms, to self‐regulating machines, and to human society.
In the West, cybernetic ideas have elicited a wide range of responses. Some view cybernetics as an embodiment of military patterns of command and control; others see it as an expression of liberal yearning for freedom of communication and grassroots participatory democracy. Some trace the origins of cybernetic ideas to wartime military projects in fire control and cryptology; others point to prewar traditions in control and communication engineering. Some portray cyberneticians' universalistic aspirations as a grant‐generating ploy; others hail the cultural shift resulting from cybernetics' erasure of boundaries between organism and machine, between animate and inanimate, between mind and body, and between nature and culture.
We can clearly see a difference between the generality of information and control theories with respect to their own well‐defined objects, and the claimed universality of cybernetics that would cover virtually all aspects of reality. In this sense, the first two can be claimed to be scientific theories in the strong sense. The last, despite its elegance, seems less a science but more a theoretical (philosophical) displacement or distortion of established scientific theories by expanding their reach towards other objects. This is actually a very controversial argument that depends on the philosophical position taken throughout this book, whose details will be presented next.
1.4 Philosophical Background
Science is a special type of formal discourse that claims to hold objective true knowledge of well‐determined objects. Different sciences have different objects, requiring different methods to state the truth value of different statements. A given science is presented as a theory (i.e. a systematic, consistent discourse) that articulates different concepts through a chain of determinations (e.g. causal or structural relations) that are independent of any agent (subject) involved in the production of scientific knowledge. This, however, does not preclude the importance of scientists: they are the necessary agents of the scientific practice. Scientific practice can then be thought as the way to produce new knowledge about a given object, where scientists work on theoretical raw material (e.g. commonsense knowledge, know‐how knowledge, empirical facts, established scientific knowledge) following historically established norms and methods in a specific scientific field to produce new scientific knowledge. In other words, scientific practice is the historically defined production process of objective true knowledge. Note that these norms, despite not being fixed, have a relatively stable structure since the object itself constrains which are the valid methods eligible to produce the knowledge effect.
Moreover, scientific knowledge poses general statements about its object. Such a generality comes with abstraction, moving from particular (narrow) abstractions of real‐world, concrete objects to abstract, symbolic ones. Particular variations of a class of concrete objects can be used as the raw material by scientists to build a general theory that is capable of covering all, known and unknown, concrete variations of that class of objects. This general theory is built upon abstract objects that provide knowledge of concrete objects. However, this differentiation is of key importance since a one‐to‐one map between the concrete and abstract realities may not exist. Abstract (symbolic) objects as part of scientific theories produce a knowledge effect on concrete objects, understood as realizations of the theory, not as a reduction or special case. At any rate, despite the apparent preponderance of abstractions, the concrete reality is what determines in the last instance the validity of the theory (even in the “concrete” symbolic reality of pure mathematics, concreteness is defined by the foundational axioms and valid operations).
To illustrate this position, let us think about dogs. Although the concept of dog cannot bark, dogs do bark. Clearly, in the symbolic reality in which the concept of dog exists, it has the ability of barking. The concept, though, cannot transcend this domain so we cannot hear in the real world the barking sound of the abstracted dog. Conversely, we all hear real dogs barking, and therefore, any abstraction of dogs that assumes that they cannot bark shall not be considered scientific at all. This seems trivial when presented with this naive example, but we will see throughout this book the implications of unsound abstractions in different, more elusive domains. This is even more critical when incorrect abstractions are accompanied by heavily mathematized (therefore consistent) models. For instance, the fact that some statement is a true knowledge in mathematical sciences does not imply it is true in economics. Always remember: a mathematically consistent model is not synonymous with a scientific theory.
Philosophy, like science, is also a theoretical discourse but with a very important difference: it works by demarcating positions as correct or incorrect based on its own philosophical system that defines categories and their relations [8]. Unlike scientific proofs, philosophy works through rational argumentation to defend positions (i.e. theses), usually trying to answer universal and timeless questions about, for example, existence of freedom. In this case, philosophy has no specific (concrete) object as sciences do; consequently, it is not a science in the way we just defined. Philosophy then becomes its own practice: rational argumentation based on a totalizing system of categories defining positions about everything that exists or not. Following this line of thought, philosophy is not a science of sciences; it can neither judge the truth value of propositions internally established by the different sciences nor state de jure conditions for scientific knowledge from the outside.
Besides, scientific and philosophical practices exist among several other social practices. They are part of an articulated historical social whole, where different practices