Newton’s Eye/Bodkin Experiment and the Principle of Undifferentiated Coding:


I work in the field of ophthalmic medical devices. I recently came across one of Sir Isaac Newton’s set of notes at the Newton project. In the notes, one particular experiment stood out to me. Newton pushed against his eye ball using a bodkin (a blunt needle) and recorded the optical sensations produced by the pressure on the eye. The schematic below drawn by Newton himself denotes the experiment. He noted:


I took a bodkin gh and put it between my eye & the bone as near to the backside of my eye as I could: and pressing my eye with the end of it (soe as to make the curvature a, bcdef in my eye) there appeared several white dark & colored circles r, s, t, &c. Which circles were plainest when I continued to rub my eye with the point of the bodkin, but if I held my eye & the bodkin still, though I continued to press my eye with it yet the circles would grow faint & often disappear until I renewed them by moving my eye or the bodkin.

He went on to note that there were different colors and types of sensations depending on if he was in a dark room or a well-lit room. I enjoyed reading through his notes because of my profession and also because it was an opportunity to peek inside a genius mind such as Newton. The experiment remined me of another great idea in Cybernetics called ‘the principle of undifferentiated coding’. This idea was proposed by another brilliant mind and one of my heroes, Heinz von Foerster. Von Foerster said:

The response of a nerve cell does not encode the physical nature of the agents that caused its response. Encoded is only ‘how much’ at this point in my body, but not what.

The brain does not perceive light, sound, heat, touch, taste or smell. It receives only neuronal impulses from sensory organs. Thus, the brain does not “see light,” “hear sounds,” etc.; it can perceive only “this much stimulation at this point on my body.” The practical consequence is that all perceptions, let alone “thoughts,” are deductions from sensory stimuli. They cannot be otherwise. All observations are therefore partly the function of the observer. This situation renders complete objectivity impossible in principle.

Ernst von Glasersfeld, the proponent of Radical Constructivism stated:

In other words, the phenomenological characteristics of our experiential world – color, texture, sounds, tastes and smells – are the result of our own computations based on co-occurrence patterns of signals that differ only with regard to their point of origin in the living system’s nervous network.

Cognition is an autonomous activity of the observer. The state of agitation of a nerve cell only codifies the intensity, not the nature of its cause. What is understood or constructed is unique to the observer. This goes against the idea that if we provide information to a person, he or she will understand what is being provided. Von Foerster would say that the hearer not the utterer determines what is being said. In Newton’s experiment, the sensations were not caused by the eye seeing lights, but due to the physical interaction on the eye. This idea is further explored by Humberto Maturana and Francisco Varela with the idea of autopoiesis. As an autopoietic being, we are all organizationally closed and any information generated is an autonomous activity of our cognitive apparatus.

Bernard Scott expands this idea further:

Von Foerster begins his epistemology, in traditional manner, by asking, “How do we know?” The answers he provides-and the further questions he raises-have consequences for the other great question of epistemology, “What may be known?”

there is no difference between the type of signal transmitted from eye to brain or from ear to brain. This raises the question of how it is we come to experience a world that is differentiated, that has “qualia”, sights, sounds, smells. The answer is that our experience is the product of a process of computation : encodings or “representations” are interpreted as being meaningful or conveying information in the context of the actions that give rise to them. What differentiates sight from hearing is the proprioceptive information that locates the source of the signal and places it in a particular action context.

Another key aspect to add to this is the idea of circularity, where the output is fedback into the cognitive apparatus.  We continue to learn based on what we already know. Thus, we can say that learning is a recursive activity. What we learn now helps further our learning tomorrow. There is no static nature when it comes to knowledge and learning. The great French philosopher Montesquieu said, “If triangles made a god, they would give him three sides.” The properties of the world (seen and unseen) are dependent on the constructor/observer. The construction/observation is ongoing and reflexive. Montesquieu also said, “You have to study a great deal to know a little.” In other words, the more you learn, the more you realize how less you know. Or simply put, “the more you know, the less you know.”

I will finish with a wonderful von Foerster story from Maturana.

Maturana tells of a time when Heinz von Foerster and the famous anthropologist, Margaret Mead went to visit Russia. While there, they went to visit a museum. Mead was using a walking stick at that time. At the entrance they learned that she could not carry her walking stick inside. Mead decided that she would not go in since she could not walk long without using the walking stick. Von Foerster convinced her to go with him. He suggested that he would hide the stick in his clothing, and once inside he would give the stick back to her. His thinking was as follows:

ln this country, whether by perfection or by design, people do not commit mistakes, therefore, any guard that sees us Inside with the walking stick will be forced to admit that we were granted a special permit because otherwise we would not be Inside with it.’

 As the story goes, they were able to visit the museum without any problems. Maturana concluded:

Heinz, by not asking beyond the entrance whether they could or not carry a walking stick, behaved as if he considered that through his interactions with the guards he could either interact with the protection system of the museum as a whole, or with its components as Independent entities, and as if he had chosen the latter. He, thus, revealed that he understood that the guards realized through their properties two non-intersecting phenomenal domains, and that they could do this without contradiction because they operated only on neighborhood relations. This allowed Heinz and Margaret Mead to move through the museum carrying what a meta- observer would have called an invisible forbidden walking stick.

Stay safe and Always keep on learning…

In case you missed it, my last post was The System in the Box:

3 thoughts on “Newton’s Eye/Bodkin Experiment and the Principle of Undifferentiated Coding:

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