TH E MA C HI N E WI TH I N PUT



In this case the whole is less richly connected internally, for one

Of the actions, or channels, is now missing.

The lessening can continue. We may find that the diagram of

Immediate effects is simply

PQ

So that the whole consists really of two parts that are functionally

Independent. In this case the whole is said to be reducible. The

Importance of this concept will be referred to later (S.13/21).

Ex.: Of the systems in Ex. 4/12/1, which are reducible?

At this minute of writing, the Laughter and Singing are

Troth sounding. Please tell me what manipulations of

Incense and organ I should make to get the house quiet, and

To keep it so.

(Hint: Compare Ex. 4/1/4.)

Ex. 2: (Continued.) Does the Singing have an immediate effect on the Laughter ?

Ex. 3: (Continued.) Does the incense have an immediate effect on the Singing ?

Ex. 4: (Continued.) Deduce the diagram of immediate effects of this machine

With input (with two parameters and two variables).

Materiality. The reader may now like to test the methods of

This chapter as an aid to solving the problem set by the following

Letter. It justifies the statement made in S.1/2 that cybernetics is not

Bound to the properties found in terrestrial matter, nor does it draw

Its laws from them. What is important in cybernetics is the extent

To which the observed behaviour is regular and reproducible.

“Graveside”

Wit’s End

Haunts.

Dear Friend,

Some time ago I bought this old house, but found it to be

Haunted by two ghostly noises— a ribald Singing and a sar-

Donic Laughter. As a result it is hardly habitable. There is

Hope, however, for by actual testing I have found that their

Behaviour is subject to certain laws, obscure but infallible,

And that they can be affected by my playing the organ or

Burning incense.

In each minute, each noise is either sounding or silent—

They show no degrees. What each will do during the ensu-

Ing minute depends, in the following exact way, on what

Has been happening during the preceding minute:

The Singing, in the succeeding minute, will go on as it was

During the preceding minute (sounding or silent) unless there

Was organ-playing with no Laughter, in which case it will

Change to the opposite (sounding to silent, or vice versa).

As for the Laughter, if there was incense burning, then it

Will sound or not according as the Singing was sounding or

Not (so that the Laughter copies the Singing a minute later).

If however there was no incense burning, the Laughter will

Do the opposite of what the Singing did.

60

T HE VER Y LAR GE S YS TE M

Up till now, the systems considered have all seemed fairly

Simple, and it has been assumed that at all times we have under-

Stood them in all detail. Cybernetics, however, looks forward to

Being able to handle systems of vastly greater complexity— com-

Puting machines, nervous systems, societies. Let us, then, con-

Sider how the methods developed so far are to be used or modified

When the system is very large.

What is meant by its “size” needs clarification, for we are

Not here concerned with mere mass. The sun and the earth form

Only a “small” system to us, for astronomically they have only

Twelve degrees of freedom. Rather, we refer to the system’s com-

Plexity. But what does that mean here ? If our dynamic system

Were a native family of five persons, would we regard it as made

Of 5 parts, and therefore simple, or as of 1025 atoms, and therefore

Very complex ?

In the concepts of cybernetics, a system’s “largeness” must

Refer to the number of distinctions made: either to the number of

States available or, if its states are defined by a vector, to the num-

Ber of components in the vector (i.e. to the number of its variables

Or of its degrees of freedom, S.7/13). The two measures are corre-

Lated, for if other things are equal, the addition of extra variables

Will make possible extra states. A system may also be made larger

From our functional point of view if, the number of variables

Being fixed, each is measured more precisely, so as to make it

Show more distinguishable states. We shall not, however, be

Much interested in any exact measure of largeness on some par-


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