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a machine built by Ross Ashby in the l940's to
demonstrate the behavior of an ultrastable system. For a
description, see Chapter 8 of Ashby, 1960.
A machine built in the l940's by W. Ross Ashby to demonstrate the behavior of an ultrastable system (see ultrastability). It responds to deviations from certain essential values of a continuous variable caused by an experimenter in the environment of the machine with stepwise structural changes, and it comes to rest only when a behavior has been found that keeps the values of that critical variable within desirable limits (see morphogenesis). The essential values maybe interpreted as a homeostatic state, goal or ideal and the structural changes are adaptive relative to these values (see homeostasis, adaptation) . (Krippendorff)