From the abstract point of view, occurs when the designer of a
Radio set, wavering between three possible circuits, finally selects
One. The third case, abstractly equivalent to the previous two,
Occurs when the owner of a radio set that has three circuits built
Into it, moves a switch to one of three positions and thereby
Selects which circuit shall actually be used. Thus, from the
Abstract point of view, selecting one machine from three is equiv-
Alent to selecting one value from three at a parameter. For exam-
ple, suppose the choice is to be between the three machines α, β
and γ (each on the states a and b);
a ba ba b α : ↓ b a β : ↓ a a γ : ↓ b b
Suppose β is selected and the selector finishes with the machine
A b
↓ a a
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A N I N T R O D UC T I O N T O C Y B E R NE T I C S
RE GU LA TI N G TH E V ER Y LA R GE SY STE M
Abstractly this selection is identical with having initially a
Machine with three-valued input:
↓
α
β
γ
(In the transformation, dots represent values that do not matter.)
If now µ is chosen, one part gives the machine
↓
a
b
a
b
b
a
a
b
A b
B a
and then deciding that the input shall be fixed permanently at β.
(The processes are identical in the sense that if some observer
Watches only the results of the processes, he cannot tell which has
Occurred except by reference to other, unmentioned, criteria.)
In this example, fixing the input at β leaves the resulting
Machine an absolute system, without input. If the result of the
Selection is to be a machine with input, then the original machine
Must start with two or more inputs, so that the fixing of one by the
Act of design selection leaves the others free for further variation
As ordinary inputs.
The designer’s act of selecting one model from many is equivalent
To some determining factor fixing an input at a permanent value.
This section treats a minor complication.)
In the examples above, the choice has been between machines
Whose transformations have had the same set of operands, i.e. the
Same set of states in the machine. What if the choice were to lie
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Between, say,
↓
The other components being ignored; while if v is chosen, the
Other part gives
↓
P q r
R q r
Thus the initial formulation is really quite general.
Design in a Black Box. It will be noticed that the operation
Of “design”, as understood here, can be carried out within a Black
Box, if it has an input. In fact, the owner of the radio set (S.13/12),
If he knows nothing of its contents, but does know how the output
Is affected by the switch, does perform the act of “design in a Black
Box” when he sets the switch and gets the desired behaviour.
Other examples extend the range of the same theme. The Black
Box, or the radio set, may be dominated by another machine,
Whose activities and values determine the switch’s position. If so,
We can say (provided we remember the sense in which we are
Using the words) that the dominating machine, when it sets the
Switch at a particular position, “designs” the radio set. What is
Important is that the dominating machine shows to the radio set
Those properties that are objectively shown by the behaviour of a
Designer.
The same point of view may be applied to the brain, and we can
See how one part of a brain can show towards another part the
Objective behavioural relationship of designer to machine. We can
Begin to see how one part— a basal structure perhaps— can act as
“designer” towards a part it dominates, towards a neural network,
Say.
Thus the idea of one machine designing another can be stated in
Exact and general terms— exact in the sense that experiment can
Be used to show objectively whether or not this relationship holds.
QU ANTI TY OF S EL EC TI ON
This aspect of design— of the reduction in numbers that
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