by     Reginald O. Kapp
Professor Emeritus in the University of London

Methodos Vol VII - No 25-26 1955
Received on August 4th 1954

The Problem

The problem that I want to discuss can best be introduced with the help of an illustration. Let it be supposed that an anti-aircraft gunner equipped with radar is watching for hostile planes. The approach or presence of one in the sky is revealed to him by a break in a line on the screen of a cathode ray oscilloscope that he is watching. When he sees the break he presses a button and releases a volley of fire. Here is a chain of successive connected events starting with the aeroplane and passing by cause and effect through the radar to the operator and on to the guns. At some link along this chain an act of observation is performed. To locate this act is the problem.

If I were setting out to make a comprehensive statement about observation I should first have to define the term. But definitions should not be introduced before they are needed and one does not need a definition in order to be able to name some of the links at which the act of observation is not performed. No one would claim, for instance, that it was performed by the guns or by the pushbutton that releases their fire. Nor would anyone claim that it was performed by the oscilloscope.

Between the oscilloscope and the pushbutton is the gunner - the operator. One can apply the term "observer" in a general way to him; but there are many links in the chain between the eye that watches the oscilloscope and the finger that presses the button. There are the afferent nerves that bring messages from the eye to the brain, a multitude of synapses in the brain itself, efferent nerves that carry controlling impulses from the brain to the operator's finger. To avoid vagueness one must discover exactly at which of the many links the act of observation occurs.

Some of these links can be ruled out as surely as those that are situated outside the operator's body. What happens on his efferent side is caused by the observation; it cannot be the observation itself, for the function of the efferent nerves is to act as instruments of control; like the operator's finger, the pushbutton, or the gun mechanism. And what happens on the afferent side is not observation but the cause of the observation. The mechanisms on that side are instruments of observation, from the oscilloscope right up to and including the afferent nerves themselves. It is true that one sometimes speaks of "the observing eye" and implies thereby that the eye is not an instrument of observation but the observer itself. How- ever, to speak thus is to use language loosely - poetically. The more precise term is "the observer's eye".

Considerations of function alone therefore lead to the conclusion, with which few physiologists would disagree, that the act of observation must occur between the afferent and the efferent systems, between the last link in the chain where the transmission of a received signal ends and the first link where the transmission of a signal of control begins. The problem is to find precisely what the link is at which the significant performance known as observation occurs.

Two hypotheses have been put forward and both need to be considered carefully; the more so as grave objections can be urged against each of them.

The first hypothesis is that the brain, or some part of it, is the observer. According to this hypothesis it would be right to speak of the "observing brain" and misleading to say "observer's brain".

The second hypothesis is that it is not the material brain but a non-material mind that performs the act of observation. This is supposed to form a link in a part of the causal chain that occurs between those parts of the brain associated with the afferent and those associated with the efferent systems. Communication between the afferent and the efferent sides is thus not regarded as direct but as being elected via an interposed non-material link, called the mind.

Those who say that the material brain is the observer are called monists; for they consider that matter constitutes the whole of reality. Those who say that a non-material mind is the observer are called dualists; for they believe that reality in its wholeness consists of two inter-acting components, one of which is material and the other non-material.

Before we consider the two alternative hypotheses we must examine the operations performed by any instrument of observation. There are really two distinct operations. One is to transmit a signal in the direction from the object observed towards the observer. The signal may consist of light waves or of longer ones, such as are received by the aerials of the radar equipment; it may be electric currents such as flow to the oscilloscope, or the nerve impulses that flow from eye to brain. The second function is to change the pattern of the signal received. For instance, the pattern on the screen of the oscilloscope in our illustration is not remotely a replica of the picture presented to a human observer when he sees an aeroplane in the sky; the pattern of chemical changes in the retina of the observer's eye is not remotely a replica of the pattern on the screen; the pattern of electric currents that pass through the afferent nerves is not remotely a replica of the pattern of chemical changes in the rods and cones of the retina. Correct conclusions about an act of observation cannot be reached unless this repeated change in pattern is appreciated.

The act of observation is thus seen to be a twofold one, consisting both in the passive reception of a pattern of signals and in the active interpretation of that pattern. Presented with a set of impulses the observer makes a correct inference. Be the observer a material brain or a non-material mind the pattern presented for observation is fundamentally different from the pattern that is inferred. Whether or not an act of interpretation is performed is not in dispute. Monists and dualists have to agree that there is interpretation. Disagreement occurs only as to what does the interpreting. 1

The Uniqueness of the Brain
Although dualists classify the brain among the instruments of observation they regard it as basically different from the other instruments along the chain. For they have to conclude that somewhere in the brain, and nowhere else, a pattern can appear that is appreciated by the non-material mind. While all the other instruments of observation transmit their signals to other material devices located along the chain, this part of the brain does not do this, but transmits instead to the non-material observer. Thus the brain appears to the dualist as an organ of inter-action between material and non-material reality.2

According to the monist hypothesis, also, the brain is unique; but for a different reason. While other devices along the chain between the aeroplane and the guns are regarded as serving the comparatively simple functions of instruments, either of observation or of control, the brain is regarded as performing the additional function of observer. It is therefore also regarded as an interpreter of patterns. At the junction between the afferent and the efferent sides, and nowhere else, it is assumed that there is a device quite unlike all the others. This is supposed to receive a certain pattern of signals, to interpret it as representing the observed object, to appreciate its significance, and to send out an appropriate pattern of signals of control to the efferent system. No functions remotely like these are supposed to be performed by the oscilloscope, or the gun-firing mechanism, or the eye, or the finger. Dualists and monists may agree that there are many links where a translation of patterns of signals into other patterns occur; and they must also agree that there is only one link at which an act basically different from translation, an act of interpretation, occurs.

Defining the Area of Disagreement
A strict analysis of an act of observation thus reveals that the area of disagreement between the two schools can be defined with great precision. The dispute turns on the simple question: What . acts as interpreter, brain or mind? But if the analysis simplifies the form of the question it does not lead to an easy answer. When the problem is expressed in terms of concrete realities objections to each of the two possible answers do not vanish but, on the contrary, become more apparent. This may explain the unwillingness that thinkers sometimes show to facing a philosophical problem in terms of concrete realities.

The question what does the interpreting? is a big one, and the answer cannot be attempted in a short paper. I must be content only to mention that much could be said both for and against each of the two possible answers; and it is perhaps not unfair to add that more can be said against than for each of them. It is important that all such arguments, the favourable as well as the unfavourable ones, be squarely faced.

The Robot Model
There I should like to leave the matter, having made such slight constructive contribution to the problem as is provided by the formulation of an uncompromising question. But consideration of the question has unfortunately been greatly confused by the introduction of another and wholly irrelevant one. And I am afraid that attempts to face those facts that are relevant will be repeatedly frustrated by the irrelevant ones so long as they are allowed to obtrude.

The irrelevant question is concerned with what may conveniently be called the "robot model". It is a question about the extent to which robots could be so designed that they would perform the various activities of living organisms. It has come to be very generally assumed that the correct answer to this question would also provide the correct answer to the questions: Where is the observer? What does the interpreting? It will be shown below that there is no connection between the questions; the belief that there is a connection results from failure to conform to a very elementary rule, the rule that in reaching any conclusion all facts used must be tested for their relevance. When this rule is not followed the result is the error in logic technically called a non sequitur. In this instance the error is committed, it will be seen below, not once, but repeatedly.

The reasoning of those who introduce the robot model into the discussion proceeds on the following lines. The operator of the anti-aircraft guns does not need to interpret the break in the line on the screen of the oscilloscope as representing an aeroplane in the sky. It suffices for him to obey an instruction received from the N.C.O. in charge of the post. He is told to press the button when the break appears on the screen and the result will be the same whether or not he understands what he is doing. And so, it is easy to see, there is no need at all for a human operator. He could be replaced by some electronic device, by a robot. This would not interpret; it would not observe. It would merely receive signals from the radar apparatus, translate their pattern into another form, and transmit the new pattern to the next link in the causal chain. Its performance would be basically of the same nature as that of any of the devices on the efferent side of the operator; and we have already seen that these do not observe or interpret. The robot would have to be correctly adjusted by the N.C.O. But it would not be required to know the reason why; only to act.

All that is true enough. There is indeed no limit to the number of elaborate and difficult performance that can be achieved by a suitably designed robot. Some of those used in gunnery incorporate ingenious computing devices. Laymen often believe, erroneously, that they solve problems in higher mathematics. But the rather common assumption is not true that this fact has any relevance to the questions where is the observer?, what does the interpreting? The purpose of using a robot, it seems to be forgotten, is to replace a human operator who must observe and interpret by a device that does not do so. The robot is, by intention, not a true model. The whole of it is on the efferent side of the person who makes use of it. Every part of it is designed to serve, like a muscle, a pushbutton, a gun mechanism as an instrument of control. It can only; be a non sequitur to reach any conclusion about the acts of observing and interpreting from the contemplation of a device deliberately designed not to perform these acts.

Testing for a Non-Sequitur
The best, perhaps the only, way of detecting a non-sequitur is to attempt to fill in the gap between facts and conclusion by more closely reasoned steps. Here the facts are that a robot can be designed for a performance identical with that of a human operator. In these days two distinct and contradictory conclusions are being erroneously drawn by various writers from these facts. They are:
a that observing and interpreting are performed by a material brain, and
b. that these acts are insignificant and questions about them meaningless.

By what logical steps is either conclusion reached? The question is not an idle one. For the custom is to present the conclusion without the intermediate steps, as though it were too self-evident to need them. And this is unfortunate. It has led to much wasted effort, which will continue unless the irrelevance is recognised. And so the above-mentioned test for a non sequitur cannot be avoided. We must attempt to reconstruct the steps in reasoning that could be inserted between facts and conclusions, even though this method must inevitably lead to a line of argument that it seems unkind to quote. For, no matter how fair one tries to be to those who base their conclusion on the robot model, every attempted passage from the facts to the conclusion cannot be made to appear better than a parody of loose reasoning. The following typical reconstructions illustrate this:

1.   "The robot is so designed that (a) no non-material link occurs in the causally connected chain of events that follow each other within the structure and (b) it does not observe or interpret. It follows that, when a human operator does observe and interpret, these acts are performed by a material link in the chain of events".

2.   "The robot has been deliberately designed so as to act without observing or interpreting. I believe, nevertheless, that it does these things. There is no non-material link in the causally connected chain of events in the robot; therefore the observing and interpreting that, according to my hypothesis, are performed by it must be done by a material link. Therefore there is no reason why observing and interpreting should not be performed by a material link in the human operator".

3.   "If one can design a robot to replace a human gunner one can design another robot to replace the N.C.O. who gives the gunner his instructions. One can also design further robots for other functions. Among these one can, according to my hypothesis, design robots capable of inventing robots, of manufacturing them, of controlling, adjusting and repairing them; one can design a complete self-contained robot community. And each individual is designed so as to act without observing or interpreting. Such a community would behave, nevertheless, exactly like a human community. This proves that the human community does no observing or interpreting. It is therefore meaningless to ask whether these functions are performed by a material brain or by a non-material mind".

Such arguments might serve as classroom exercises, in which the students would be asked to name, classify and explain the fallacies. There is no need to dilate on them here. But has anyone provided any closely reasoned steps from the robot model to any conclusion about observing and interpreting that did not contain these or similar fallacies? Is it possible to devise across that gap a row of closely reasoned steps that are free from errors in logic? I have tried to devise them but have failed. And so the big questions remain as puzzling now. as they were when engineering devices were not quite so ingenious and elaborate as they are to-day.


In this Paper we find within the field of anatomy and physiology, if not even of cybernetics, one of the oldest and most classical problems in philosophy and science: the problem of observation and knowledge. Professor Kapp mentions his difficulties about observation and shows why the robot model fails to overcome them.

It would not be appropriate in a comment to review the whole ground, but we should like to mention two aspects that have been emphasised by us elsewhere. They are respectively the original source of the difficulties mentioned by Professor Kapp, and the reason why it is only because of the traditional way in which the problem of observation has been tackled in philosophy that the difficulty arises.

The origin of the difficulty lies far back in time. When the Greeks enquired into the relation between words and the things designated by the words they sought an answer, not in unspecified things, and in a specified relation bearing upon them, but in the things they already were using as words and as named things. That gave them no opportunity for considering the relation, i.e, the operations of semantisation. On the contrary, that suggested to them the addition of something new between the words and the named things. It was an activity, that they called knowing, and was regarded as something passing between the named thing and the person who was applying the name, and informing him, by means of its differences, of the differences between one named thing and the others. It followed from this approach that the activity of knowing could only be described in terms of an irreducible metaphor and that any attempt at literal description must lead to a contradiction.

Since knowing is the motion of something, location was attributed to all named things; and since knowing is information about differences between named things, all named things were regarded as being differentiated in themselves and by themselves, Hence, all named things, being regarded as occupying different regions of space by means of the differences between themselves, became physical things.

This view soon led to trouble. Some of the things that we name are not physical things: how are they to be explained? The Greeks did so by attributing location to these too, be it by locating them in the world of the Gods or in a mind or consciousness conceived as a point in space, without extension. Those who refused to attribute this kind of location for fear of being called mystics or, a more approbrious epithet in some circles, psychologists leaved uncoupled the words of the things lacking, i.e, leaved these words without semantical relation. The development of the introduction of knowing in philosophy and science since the days of Thalea, Alcmeon, Empedocles, Lencippus, Democritus, etc. is, however, somewhat beside the point.

Let us turn instead to the present attitude of those who, perhaps equipped with the most refined and scientific observational technique, are seeking to understand the nature of observing regarded as knowing, of observer regarded as knower. l"or they start with the assumption that the things have already been located and differentiated, they direct their attention, not to the activities by which the things are located and differentiated, but to a passive activity, at the best an activity of discovering.

This is as thought a person were to seek to understand the nature of painting, not by observing painters at work, but them in a world which is from the beginning a picture gallery.

For these reasons we agree with Professor Kapp when he fails to find the observer and the act of observing while studying some piece of a machine, not as a working piece, but as a statical one; and we also agree when he expresses his dissatisfaction with the solution that has hitherto been offered. But these difficulties only arise because he adopts the traditional view of knowledge, they are a result of the historical development in philosophy and not intrinsic. Only this traditional approach leads to the view that a human being could not in principle be copied by a mechanical model and that machines capable of reproduction are inherently impossible.

Those things about man that can be expressed without having to resort to irreducible metaphors or revealing contradictions are in theory capable of being copied like any other model.


(For an analysis of observing made by our operational School, see for instance my writing a Consapevolizzazione dell'osservare, Mod. 3. Atti del Congresso di Studi Metodo-logici, Torino, 17-20 dicembre 1952, Edizioni Ramella, Torino, 1954).

Mr. Ceccato has drawn attention to an all too common error in philosophical thinking. It is to confuse the meaning of the words to be and to do. Mr. Ceccato says quite rightly that people in the past have hoped by studying what things are like to learn about the things that they do and are done to them. This was one of the basic errors in the once fashionable philosophy of emergence advocated by Alexander, Lloyd Morgan and others, as I pointed out in my book Science v Materialism . The same error is made by those who pin their faith to the robot analogy. I agree with Mr, Ceccato that a living organism is essentially a machine, that the difference between a man's body and a life-like robot is not basic. But the conseguences of this view have to be faced squarely. They are generally dodged and this perhaps because they are particularly disconcerting to just those followers of traditional thought whom Mr. Ceccato refers to.

A robot works in a specific way only when specific things are done to it. It does not do so when left to the random, unspecific influences of its environment. A man is basically a machine. Therefore, one must infer, he also works in a specific way only when specific things arc done to him, not if left entirely to the random unspecified influences of his environment. The agent that does the specific things to the robot is a human operator; he handles levers, push buttons, rheostats, adjusting screws and other controlling devices. The agent that does specific things to the human machine is, as just pointed out, not in the material environment. So the conclusion to be drawn from the robot analogy is that this agent is non-physical and lacks location. One name is "life" but I prefer the less committal term "a diathete". It is most odd how those who stress the mechanical analogy always argue in exactly the opposite way. It only shows how necessary is the kind of guidance along logical lines provided by Mr Ceccato’s remarks.

1   We are no more conscious of performing an act of interpretation during an observation than we are of the nature of the various patterns presented, to the brain when electrical impulses reach it from the organs of sense perception. But consciousness is no criterion of reality. That interpretation is performed unconsciously does not alter the fact that it is performed; for every physiologist knows that there is a change of pattern between what is presented to the eye by the object observed and what is presented to the brain by the afferent nerves.
2   There are good reasons why the dualist, if he is consistent, must regard the whole of living substance as forming a region of interaction between the two component parts of reality, and therefore provided with devices adapted to the function of interaction. EIsewhere ( Mind, Life and Body Constable) I have described these devices as "eudiathetous mechanisms". There is, however, no need at the present moment to consider interaction in such general terms.

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