Volume 18 of W. Ross Ashby's Journal
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Summary: An organism cab control an environment of its own size (channel capacity), but not
more. Constraint in environment
Summary: An error-controlling regulator cannot reduce the incoming variation to less than a
half. But see 4688
Summary: Error-controlled regulation is possible only by blocking conduction.
Information and observer
Epistemology : When variety arrives, the observer who sees all sees unity changing to diversity;
the element in the set sees diversity change to unity. 4691.
Summary: In information, the point of view of the element is very different from that of the
set. Searching variety in
Homeostat its discontinuous 2nd order process can be changed through intermediates to that of
thermostat Markov process / chain can be modified to give a field Regulation discontinuous and continuous are related Trial and error relation to continuous stability
Summary: Progression to an absorbing state in a Markov chain and progression along a line of
behaviour in a stable, continuous system are two extremes of a continuous scale. 4842
Design amount of, partitioned
Summary: If a designer is only partly responsible for the determination of a machine, the fraction
(implied by "partly") can be given meaning only if there is no loss of variety in
Summary: A determinate machine, with single-valued field, can be formed only by supplying variety
of n log n bits. 4722 Homeostat quantity of design in
Homeostat flow of variety in
Summary: The unreliability of introspective evidence.
Equilibrium Riguet's definition
Summary: Riguet's statement of "relational mechanics." 4751 Regulation implies both activity and non-activity
Summary: Regulation implies both activity of the regulator and inactivity of the essential
Tensor properties collected
Summary: Properties of tensor product.
Summary: I am able to approach the subject of the origin of intelligence, i.e. regulation,
from two points of view, but do not seem to be able to relate them.
Summary: Why regulation?
Variety in product-machine
Summary: Every machine on states M defies "machines" on states in M. Only in the latter is variety bound to fall. (Its "tensor powers") (n=1,2,...) n 4869
Summary: "Transformation". Disturbance repetitive disturbance Mapping and transformation Transformation definition of
Summary: Levels in regulation. Regulation levels in regulation
Summary: Learning is worth while only when the disturbance will be repeated. Learning useful against repetition
Discrimination is it a problem? Feedback discriminative
Summary: The "problem" of discriminative feedback must be shown to exist in the real environment.
Summary: Machines, with inputs and outputs, treated wholly by mappings. All this is, in substance, identical with Riguet's form. 4867. Simpler , 4876 4991
Summary: Feeding a machine with input and output back into itself. Evolution as process
Natural Selection : Huxley and Fisher on Evolution (extracts from book) 4861.
Summary: Why the uniselectors have many values. 5046
Summary: Specifying the second-order feedback rigorously.
Regulation multiplicity of aims
Summary: Speed is merely one of many demands that can made to qualify simple adaptation. 4964 Optimum selecting efficiently Selection definition of object by reference to others
Summary: All sorts of continuous and discontinuous systems put together to make all sorts of
Summary: Relation of the physicist's "entropy" to my work.
Epistemology : The method of getting absoluteness by using past values is essentially second-rate
Summary: When a system is partly unobservable, the method of trying to restore absoluteness
by taking earlier values into account is fundamentally second-rate; it will succeed
only when the case is peculiarly favourable. 4979
Discrimination feedback for discimination Feedback third order
Summary: All necessary improvements to the basic ultrastable system can be had by the addition
of further orders of feedback. Chess organisation for
Summary: We live by the incorporation of pieces that are already keepers-out of noise. Determinate why important
Summary: Living organisms surround themselves with invariants.
Summary: Example of an adequate channel. Pantagruel, l.iii,ch.xxix Invariant utility of
Summary: With a random transformation the variety tends to fall to two thirds at each step.
Summary: "Time" can be treated as a disturber of a machine, like an input. Time as disturber
Summary: Research and the strategy of adaptation.
Epistemology : A set of states suitable for investigation must satisfy EXPRESSION
Summary: However many states are available, the experimenter confines himself to some set satisfying
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2008 © The Estate of W. Ross Ashby