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4. "Completeness," in the sense of being able to define within the language all effective representations and operators, should be provided so that the language itself places no long-term limits on the adaptive plan. |
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What follows is an outline of one "language" satisfying these conditions. It has the additional property (which will be discussed after the presentation) of offering straightforward representations of several models of natural systems, including operon-operator models, cell-assembly models (section 3.6) and various physical signaling and radiation models. |
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The basic units of the language are broadcast units. Each broadcast unit can be thought of as broadcasting an output signal "to whom it may concern" whenever it detects certain other signals in its environment. For example, a given unit, upon detecting the presence of signals I and I' (perhaps broadcast by other units), would broadcast signal I". Some broadcast units actually process signals so that the signal broadcast is some modification of the signals detected. In keeping with suggestion (1), broadcast units are specified by strings of symbols. A set of broadcast units, usually combined in a string, will constitute a device or structure (an element of  ). Some broadcast units broadcast strings which can be interpreted as (new) broadcast units; broadcast units can also detect the presence of other broadcast units (treating them as signals). Thus, given broadcast units can modify and create othersthey serve as operators on . |
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The language's ten symbols  , along with informal descriptions of intended usage, follow. (Exact interpretations for strings of the symbols follow the listing.) |
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| 0 | These two symbols constitute the basic alphabet for specifying | | 1 | signals. Thus 01011 is a signal which, within the language, has no other meaning than its ability to activate certain broadcast units. Generally a string such as 01011 will be interpreted as the name of a particular signal (e.g. the binary encoding of a frequency or amino acid sequence). | | * | * indicates that the following string of symbols (up to the next occurrence of a *, if any) is to be interpreted as an active broadcast unit. | | : | This symbol is the basic punctuation mark, used in separating the arguments of a broadcast unit. |
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For example, *1100:11 designates a broadcast unit which will broadcast the signal 11 one unit of time after the signal 1100 is detected in the unit's environment (see the intended interpretations for strings below). |
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