A RELAY is, as I have pointed out already, irreversible.
Diathesis can pass through it in one direction and
not in the other. As a path for diathesis consists of relays
in cascade the whole path is also irreversible. Which is
only another way of saying that in our foundry the
switches that enable the craneman to control the casting
do not enable the casting to control the craneman.
This irreversibility enables one to speak of a path for
diathesis. The relay to be found at the end might be
called the last relay and the one at the beginning the
first relay. For a reason that will appear in a moment
I propose also to call the first one a primary relay. The
others might then be called intermediate relays.
If one asks how the last or any intermediate relay is
controlled the answer is simple enough. It is controlled
by the relay one stage nearer to the beginning of the path.
The contactors are controlled by the switches in the crane
cabin, these switches by the craneman's muscles, his
muscles by endplates, these by his nerves, and so forth.
And somewhere near the beginning of any path one can
say, in more general terms that relay number 4 is
controlled by relay number 3; relay number 3 by relay
number 2; relay number 2 by relay number 1.
And there the recital must end. If one asks by what
relay number one is controlled the answer cannot be by
another relay. For there is none. A primary relay is
controlled, certainly. But it must be done by means
that differ in principle from the means by which every other
relay in the set is controlled. It is this difference that
justifies the name of primary relay. How and by what is a
primary relay controlled.
The question is, surely, very relevant, very important
in science. Some scientists will, I am hoping, find in it
a stimulating challenge. And yet. The question is disconcerting. I can well believe that some will find it
irksome. Not that it is unreasonable. Anyone who says
that a particular device is controlled by some other device
must expect the question by what is that other device
controlled. One of the things that makes the question
disconcerting is that its logic is too simple to be easily
ignored. One would like to be able to say that, hidden
somewhere among the tissues of the brain, there must
be a further device in control of the one that I have called
a primary relay. And this easy way out is so obviously
barred by the definition of a primary relay. As soon as
one says that there must be a further device one realises
that, if there were, this would be the primary relay and
the question would remain as before, unanswered.
The truth is that the question what controls a primary
relay is off all the traditional paths of scientific enquiry.
And so the traditional methods by which scientists have
successfully tackled their problems do not promise much
help here. And the solution when it comes is not likely
to fit readily into the existing body of accumulated
scientific knowledge. It may shake some traditional
notions that have come to be regarded as firmly established.
Those who realise this may well hope that the question
will soon come to be ignored and forgotten. They may
well attempt to discourage those who would take it
seriously. And if they cannot dismiss it they may well
clutch eagerly and uncritically at the first facile answer
that presents itself. It is one of the weaknesses of human
nature (as is proved time and time again by political,
religious, philosophical, and sometimes even scientific
controversy) to prefer an unsound solution of a problem,
provided only that it be comforting, to a sound one that is
disturbing. An imp of complacency dwells in every one of
us and urges us to dodge awkward questions. He will
certainly urge us to stop asking what controls a primary
Here are some of the things that the imp may whisper
in our ears:
"This is not a real question at all. It has been
artificially manufactured out of the words that have
been used to form it. It melts away under the fierce
light of logical scrutiny."
"The time is not yet for such a question. Let
scientists first find out more about the working of the
brain. When they have observed a primary relay they
will see how it works. Then they will know what
controls it and how the control is effected." (But, let
me repeat, they will not observe what controls it. For
if they did, the thing observed would, in turn, become
the primary relay.) "The question is really quite
simple. It has been answered by scientists and they
have since proceeded to more important things."
"There is no such thing as a primary relay. Processes
in the brain are controlled by the sense data received as
stimuli from the outer world. Hence the series of relays
does not have its beginning in the brain. It only passes
through that organ. The series is infinitely long."
Whether such arguments will be regarded as foolish
or plausible I do not know. They are certainly not too
foolish to have found spokesmen among scientists of
repute, as I have found both from my reading and from
conversation. So the unsoundness of the arguments is
evidently not immediately apparent. It is only exposed
after a critical examination. I am obliged to consider
quite seriously at least the argument that the question is
not real and the argument that there is no device to which
the term primary relay could apply.
Those who may think that the question has been artificially manufactured from the words in which it is
presented could clairn (and no doubt with some justification) that I ought to have expressed my meaning
differently. Some might object to my choice of the word
"diathesis". They might prefer a longer word. Or
alternatively they might prefer a shorter one, such as
"control". Some might object to my way of speaking of
diathesis as though it flowed from one place to another.
(And it is worth noting here that it is equally possible to
object to speaking of energy in that way.) Some might
think that the definition is too inclusive. Others that it
is not inclusive enough. And then one might argue with
some reason that such devices as contactors, switches,
muscle fibres, nerves, synapses ought not to be called
relays. Neither engineers nor physiologists apply the word
to any of these particular devices. Indeed a physiologist
would describe the whole process by which the system of
voluntary muscles is controlled in different terms from
those that I have used. Having been reminded of all
this by the imp of complacency one might be tempted to
forget the irksome question about the control of a primary
However, it is facts that matter and not words. Be it
admitted that I could have pursued my investigation
along a more traditional path, that I could have found a
neater, clearer, more cogent formulation of the question.
That would not prove that the question itself does not
exist. What must be remembered is that the question
would have presented itself in different words if I had
approached it differently; but it would liave presented
For it is a fact that a series of material devices is situated
between the craneman's brain and the casting. It is a
fact that these devices are so arranged that each touches
off the next one in the series when it operates. It is,
therefore, also a fact that they are all touched off in
succession when the very first one operates. Whether this
first one be called a primary relay or by any other name
it remains true that it is the first of a series. This first
device is touched off at the required moment and only
at that moment. So it is controlled. By what? How?
Such questions are not created by words and cannot be
abolished by words. But words do have the power to
obscure them. And there is quite a real danger that this
It is so very tempting to allow one's attention from
unwelcome facts to be diverted by discussion about
definitions or the choice of the best terms or anything else
that is not relevant. One may think that one is making an
honest attempt to formulate a problem more clearly;
but one is really, by one's exaggerated preoccupation
with definitions, trying unconsciously to dodge it.
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