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W. Ross Ashby citations

William Ross Ashby est un psychiatre-ingénieur anglais venu très tôt à la cybernétique et son influence est telle que Ludwig von Bertalanffy l’a mentionné pour sa contribution qui a influencé Norbert Wiener, Herbert Alexander Simon et les autres.

Il a répandu le concept d'homéostasie, équilibre des fonctions vitales de la vie, par un appareil, l'homéostat, qui présente cette caractéristique, nouvelle dans les années cinquante, de combattre des perturbations externes infligées volontairement dans le but d'en perturber le fonctionnement. La machine rééquilibre dans une position fixe des plaquettes soumises à des courants contradictoires dans des bains acidulés entraînant des variations de positions qu'elle corrige d'elle-même pour ramener l'ensemble à une position moyenne fixe. Une démonstration de l'homéostat figure dans un film, « La Cybernétique » de Jean-Marie Piquint.

De Ashby, la Loi de la variété requise est la plus connue. La « variété » est le dénombrement de la quantité de comportements et d’états différents mesurés pour un système donné.

Pour qu’un système « A » puisse contrôler un système « B », il faut et il suffit que la variété de « A » soit supérieure ou au moins égale à celle de « B ». Il s’ensuit qu’une « inversion de contrôle » se produit lorsque la variété du « commandé » augmente et dépasse celle du « commandeur ». C’est la version cybernétique de la « dialectique du maître et de l’esclave » chez Hegel. À force de travailler au service du maître, l’esclave acquiert de plus en plus de compétences tandis que le maître perd ses compétences initiales à force de se faire servir et, alors, l’esclave devient le maître de son ancien maître qui devient le nouvel esclave de son ancien esclave !

Ashby a beaucoup travaillé sur l’augmentation de l’intelligence et participe aux travaux sur l’intelligence artificielle, sur la complexité reliée à la variété et sur les origines de l’ordre exprimées par le principe de von Foerster Order from Noise et le principe de Schrödinger Order from Order. Le premier est un processus stochastique du hasard et de la nécessité dans la perspective d'une explication cybernétique où une « réponse appropriée » aux contraintes de l'environnement et du contexte a de meilleures chances de survie, de développement et de reproduction parmi toutes les occurrences possibles et le deuxième est un principe d’organisation par extension. Le principe Order from Noise est aussi un principe d’auto-organisation et de complexité. En Europe, Edgar Morin et Henri Atlan posent que la condition de l’auto-organisation est la « redondance » initiale élevée qui n’est autre que la « variété » de Ashby. Ces principes sont étendus à l'étude, sous un éclairage nouveau, de nombreuses disciplines telles que le droit, les relations humaines, etc. sous l'influence de Louis Couffignal, Aurel David et Georges R. Boulanger. Wikipedia  

✵ 6. septembre 1903 – 15. novembre 1972
W. Ross Ashby: 26   citations 0   J'aime

W. Ross Ashby: Citations en anglais

“All the changes that may occur with time are naturally included, for when plants grow and planets age and machines move some change from one state to another is implicit.”

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W. Ross Ashby

Source: An Introduction to Cybernetics (1956), Part I: Mechanism, p. 9: Chapter 2 Change, lead paragraph.
Contexte: The most fundamental concept in cybernetics is that of "difference", either that two things are recognisably different or that one thing has changed with time. Its range of application need not be described now, for the subsequent chapters will illustrate the range abundantly. All the changes that may occur with time are naturally included, for when plants grow and planets age and machines move some change from one state to another is implicit. So our first task will be to develop this concept of "change", not only making it more precise but making it richer, converting it to a form that experience has shown to be necessary if significant developments are to be made.

“Cybernetics treats not things but ways of behaving.”

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Source: An Introduction to Cybernetics (1956), Part I: Mechanism, p. 1; As cited in: Stuart A. Umpleby, "Ross Ashby's general theory of adaptive systems." International Journal of General Systems 38.2 (2009): 231-238.
Contexte: Cybernetics treats not things but ways of behaving. It does not ask “what is this thing?” but “what does it do?”... It is thus essentially functional and behaviouristic. Cybernetics deals with all forms of behavior in so far as they are regular, or determinate, or reproducible. The materiality is irrelevant... The truths of cybernetics are not conditional on their being derived from some other branch of science. Cybernetics has its own foundations.

“During the last few years it has become apparent that the concept of "machine" must be very greatly extended if it is to include the most modern developments. Especially is this true if we are studying the brain and attempting to identify the type of mechanism that is responsible for the brain’s outstanding powers of thought and action. It has become apparent that when we used to doubt whether the brain could be a machine, our doubts were due chiefly to the fact that by ‘‘machine’’ we understood some mechanism of very simple type. Familiar with the bicycle and the typewriter, we were in great danger of taking them as the type of all machines. The last decade, however, has corrected this error. It has taught us how restricted our outlook used to be; for it developed mechanisms that far transcended the utmost that had been thought possible, and taught us that ‘‘mechanism’’ was still far from exhausted in its possibilities. Today we know only that the possibilities extend beyond our farthest vision.”

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W. Ross Ashby (1951), "Statistical Machinery". In: Thales Vol 7. p.1 as cited in: Peter M. Asaro (2008) " From Mechanisms of Adaptation to Intelligence Amplifiers: The Philosophy of W. Ross Ashby http://cybersophe.org/writing/Asaro%20Ashby.pdf"

“Duration of selection. At this point a word should be said about how long a given act of selection may take, for when actual cases are examined, the time taken may, at first estimate, seem too long for any practical achievement. The question becomes specially important when the regulator is to be developed for regulation of a very large system. Approximate calculation of the amount of selection likely to be necessary may suggest that it will take a time far surpassing the cosmological; and one may jump to the conclusion that the time taken in actually achieving the selection would have to be equally long. This is far from being the case, however.”

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Source: An Introduction to Cybernetics (1956), Part 3: Regulation and control, p. 260

“Throughout, we shall be exemplifying the thesis of D. M. MacKay: that quantity of information, as measured here, always corresponds to some quantity, i. e. intensity, of selection, either actual or imaginable”

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Source: An Introduction to Cybernetics (1956), Part 3: Regulation and control, p. 252

“If intellectual power is to be developed, we must somehow construct amplifiers for intelligence — devices that, supplied with a little intelligence, will emit a lot.”

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W. Ross Ashby

Ashby. "Design for an intelligence amplifier." Automata studies (1956): 215-234. p. 216

“Variety can destroy variety.”

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W. Ross Ashby

Source: An Introduction to Cybernetics (1956), Part 3: Regulation and control, p. 207

“The primary fact is that all isolated state-determined dynamic systems are selective: from whatever state they have initially, they go towards states of equilibrium. These states of equilibrium are always characterised, in their relation to the change-inducing laws of the system, by being exceptionally resistant.”

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Source: Design for a Brain: The Origin of Adaptive Behavior (1952), p. 238

“The most basic facts in biology are that this earth is now two thousand million years old, and that the biologist studies mostly that which exists today.”

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W. Ross Ashby

Source: An Introduction to Cybernetics (1956), Part 3: Regulation and control, p. 196

“Every stable system has the property that if displaced from a state of equilibrium and released, the subsequent movement is so matched to the initial displacement that the system is brought back to the state of equilibrium. A variety of disturbances will therefore evoke a variety of matched reactions.”

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W. Ross Ashby

Source: Design for a Brain: The Origin of Adaptive Behavior (1952), p.54

“Two main lines are readily distinguished. One already well developed in the hands of von Bertalanffy and his co-workers, takes the world as we find it, examines the various systems that occur in it - zoological, physiological, and so on - and then draws up statements about the regularities that have been observed to hold. This method is essentially empirical. The second method is to start at the other end. Instead of studying first one system, then a second, then a third, and so on, it goes to the other extreme, considers the set of all conceivable systems and then reduces the set to a more reasonable size. This is the method I have recently followed.”

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Ashby (1958) "General Systems Theory as a new Discipline". General Systems, 3 (1958). p. 1-6; cited in: Ludwig von Bertalanffy (1968) General System Theory. p. 94-95

“As shorthand, when the phenomena are suitably simple, words such as equilibrium and stability are of great value and convenience. Nevertheless, it should be always borne in mind that they are mere shorthand, and that the phenomena will not always have the simplicity that these words presuppose.”

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Source: An Introduction to Cybernetics (1956), Part I: Mechanism, p. 85

“There comes a stage, however, as the system becomes larger and larger, when the reception of all the information is impossible by reason of its sheer bulk. Either the recording channels cannot carry all the information, or the observer, presented with it all, is overwhelmed. When this occurs, what is he to do? The answer is clear: he must give up any ambition to know the whole system. His aim must be to achieve a partial knowledge that, though partial over the whole, is none the less complete within itself, and is sufficient for his ultimate practical purpose”

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Source: An Introduction to Cybernetics (1956), Part I: Mechanism, p. 106, as quoted in: " An Introduction to Cybernetics http://www.ecotopia.com/webpress/nurcap/cybernetics198803.htm," at ecotopia.com

“Every isolated determinate dynamic system, obeying unchanging laws, will ultimately develop some sort of organisms that are adapted to their environments.”

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Ashby (1962), quoted in: V. Lawrence Parsegian (1972) This cybernetic world of men, machines, and earth systems'. p. 178: About the principle of self-organization

“Cybernetics was defined by Wiener as “the science of control and communication, in the animal and the machine” — in a word, as the art of steermanship, and it is to this aspect that the book will be addressed. Co-ordination, regulation and control will be its themes, for these are of the greatest biological and practical interest.
We must, therefore, make a study of mechanism; but some introduction is advisable, for cybernetics treats the subject from a new, and therefore unusual, angle… The new point of view should be clearly understood, for any unconscious vacillation between the old and the new is apt to lead to confusion.”

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Source: An Introduction to Cybernetics (1956), Part I: Mechanism, p. 1: Lead paragraph

“Further, as every law of nature implies the existence of an invariant, it follows that every law of nature is a constraint.”

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W. Ross Ashby

Source: An Introduction to Cybernetics (1956), Part 2: Variety, p. 130

“By a state of a system is meant any well-defined condition or property that can be recognised if it occurs again. Every system will naturally have many possible states.”

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Source: An Introduction to Cybernetics (1956), Part I: Mechanism, p. 25

“The invasion of psychology by cybernetics is making us realize that the ordinary concepts of psychology must be reformulated in the language of physics if a physical explanation of the ordinary psychological phenomena is to become possible. Some psychological concepts can be re-formulated more or less easily, but others are much more difficult, and the investigator must have a deep insight if the physical reality behind the psychological phenomena is to be perceived”

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W. Ross Ashby, "Review of Analytical Biology, by G. Sommerhoff." In: Journal of Mental Science Vol 98 (1952), p. 88; As cited in Peter M. Asaro (2008)

“Cybernetics is likely to reveal a great number of interesting and suggestive parallelisms between machine and brain and society. And it can provide the common language by which discoveries in one branch can readily be made use of in the others… [There are] two peculiar scientific virtues of cybernetics that are worth explicit mention. One is that it offers a single vocabulary and a single set of concepts suitable for representing the most diverse types of system… The second peculiar virtue of cybernetics is that it offers a method for the scientific treatment of the system in which complexity is outstanding and too important to be ignored. Such systems are, as we well know, only too common in the biological world!”

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Source: An Introduction to Cybernetics (1956), Part I: Mechanism, p. 4-5

“[Constraint] is a relation between two sets, and occurs when the variety that exists under one condition is less than the variety that exists under another.”

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W. Ross Ashby

Source: An Introduction to Cybernetics (1956), Part 2: Variety, p. 127

“The concept of "variety" [is] inseparable from that of "information."”

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Source: An Introduction to Cybernetics (1956), Part 2: Variety, p. 140

“Its importance is that if R[egulator] is fixed in its channel capacity, the law places an absolute limit to the amount of regulation (or control) that can be achieved by R, no matter how R is re-arranged internally, or how great the opportunity in T. Thus the ecologist, if his capacity as a channel is unchangeable, may be able at best only to achieve a fraction of what he would like to do. This fraction may be disposed in various ways —he may decide to control outbreaks rather than extensions, or virus infections rather than bacillary — but the quantity of control that he can exert is still bounded. So too the economist may have to decide to what aspect he shall devote his powers, and the psychotherapist may have to decide what symptoms shall be neglected and what controlled.”

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W. Ross Ashby

Source: An Introduction to Cybernetics (1956), Part 3: Regulation and control, p. 245: Regarding the law of requisite variety

“Many workers in the biological sciences — physiologists, psychologists, sociologists — are interested in cybernetics and would like to apply its methods and techniques to their own specialty. Many have, however, been prevented from taking up the subject by an impression that its use must be preceded by a long study of electronics and advanced pure mathematics; for they have formed the impression that cybernetics and these subjects are inseparable.
The author is convinced, however, that this impression is false. The basic ideas of cybernetics can be treated without reference to electronics, and they are fundamentally simple; so although advanced techniques may be necessary for advanced applications, a great deal can be done, especially in the biological sciences, by the use of quite simple techniques, provided they are used with a clear and deep understanding of the principles involved. It is the author’s belief that if the subject is founded in the common-place and well understood, and is then built up carefully, step by step, there is no reason why the worker with only elementary mathematical knowledge should not achieve a complete understanding of its basic principles. With such an understanding he will then be able to see exactly what further techniques he will have to learn if he is to proceed further; and, what is particularly useful, he will be able to see what techniques he can safely ignore as being irrelevant to his purpose.”

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W. Ross Ashby

Preface
An Introduction to Cybernetics (1956)

“[T]he concept of “feedback”, so simple and natural in certain elementary cases, becomes artificial and of little use when the interconnexions between the parts become more complex. When there are only two parts joined so that each affects the other, the properties of the feedback give important and useful information about the properties of the whole. But when the parts rise to even as few as four, if every one affects the other three, then twenty circuits can be traced through them; and knowing the properties of all the twenty circuits does not give complete information about the system. Such complex systems cannot be treated as an interlaced set of more or less independent feedback circuits, but only as a whole.
For understanding the general principles of dynamic systems, therefore, the concept of feedback is inadequate in itself. What is important is that complex systems, richly cross-connected internally, have complex behaviours, and that these behaviours can be goal-seeking in complex patterns.”

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Source: An Introduction to Cybernetics (1956), Part I: Mechanism, p. 54 as cited in: Margaret A. Bode (2006) Mind as Machine: A History of Cognitive Science, Volume 1. p.229

“When a constraint exists advantage can usually be taken of it.”

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Source: An Introduction to Cybernetics (1956), Part 2: Variety, p. 130

“The fundamental questions in regulation and control can be answered only when we are able to consider the broader set of what it might do, when “might” is given some exact specification.”

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Source: An Introduction to Cybernetics (1956), Part 2: Variety, p. 121