On Attaining Spiritual Sight (Part I)

[Federica]

Last year in this thread we had a long discussion on Steiner's views on heart function, and sensory and motor nerves. I feel that an important element was not mentioned then, which I believe brings something fundamental to what Steiner meant with his famous contention that motor nerves don't exist. I am not trying to reopen that discussion, I simply want to add this element for future reference. I think it makes an important difference.

As we said, Steiner meant that the physical correlate of soul activity is the entire physical body (no domino effects), however just as soul activity is differentiated in TFW, so its physical correlate is respectively differentiated in nerve function (T) rhythmic function of breathing and blood flow (F) and metabolism (W). Now, what we did not pointed to previously is that these three physical correlates are not to be conceived simplistically - respectively located in the upper, median, and lower body; working in parallel. Rather, they all extend to the entire body and they are continually intermingled, in all organs and systems. So we shouldn't think: "nervous activity=nerves".

In particular, the nerves are the locus of nervous activity 'proper', but also of metabolic and rhythmic activity (the physical correlates of will and feeling). And, Steiner considers that nervous activity proper (the correlate of ideation/representation) "cannot possibly be an object of physiologically empirical observation". This is because the only perceivable thing in representation is the reflection, the receding images, thus the activity that causes them to recede can't be observed empirically. Therefore, whatever can be natural-scientifically observed inside the nerves is not what Steiner means with 'nervous activity'. Those observations are rather metabolic and/or rhythmical activity taking place within the nerves.

Anatomy and Physiology must bring themselves to recognize that neural function can be located only by a method of exclusion. The activity of the nerves is precisely that in them which is not perceptible by the senses, though the fact that it must be there can be inferred from what is so perceptible, and so can the specific nature of their activity. The only way of representing neural function to ourselves is to see in it those material events, by means of which the purely psycho-spiritual reality of the living content of ideation is subdued and devitalized to the lifeless representations and ideas we recognize as our ordinary consciousness. Unless this concept finds its way somehow into physiology, physiology can have no hope of explicating neural activity.

Ch VII of Riddles of the Soul / The case for Anthroposophy

https://rsarchive.org

Moreover, motion as "effusion of the will" is not really a phenomenon of the organism, but of the interrelation of the organism with its environment. The only physical correlate of the will within the organism is not physical movement, which goes beyond it, but the will's metabolic correlate, including what experiments capture as measurable activity located within the nerves. The metabolic process in the nerve can be measured, the nervous function proper cannot.

Exerting volition, the life of the psyche overreaches the domain of the organism and combines its action with a happening in the outer world. — The study of the whole matter has been greatly confused by the separation of the nerves into sensory and motor. Securely anchored as this distinction appears to be in contemporary physiological ideas, it is not supported by unbiased observation. The findings of physiology based on neural sections, or on the pathological elimination of certain nerves, do not prove what the experiment or the case-history is said to show. They prove something quite different. They prove that the supposed distinction between sensory and motor nerves does not exist. On the contrary, both kinds of nerve are essentially alike. The so called motor nerve does not implement movement in the manner that the theory of two kinds of nerve assumes. What happens is that the nerve as carrier of the neural function implements an inner perception of the particular metabolic process that underlies the will—in exactly the same way that the sensory nerve implements perception of what is coming to pass within the sense-organ. Unless and until neurological theory begins to operate in this domain with clear concepts, no satisfactory co-ordination of psychic and somatic life can come about.

Ch VII of Riddles of the Soul / The case for Anthroposophy

https://rsarchive.org/

PS: Also interesting to read Owen Barfield's note nr 3 to the quoted chapter VII of Riddles of the Soul, which he translated. Indeed, in neuroscience the foundation of the common theory, accepted to this day, is the so-called "neuron doctrine" developed in the late 1800s.

[AshvinP]

Exerting volition, the life of the psyche overreaches the domain of the organism and combines its action with a happening in the outer world. — The study of the whole matter has been greatly confused by the separation of the nerves into sensory and motor. Securely anchored as this distinction appears to be in contemporary physiological ideas, it is not supported by unbiased observation. The findings of physiology based on neural sections, or on the pathological elimination of certain nerves, do not prove what the experiment or the case-history is said to show. They prove something quite different. They prove that the supposed distinction between sensory and motor nerves does not exist. On the contrary, both kinds of nerve are essentially alike. The so called motor nerve does not implement movement in the manner that the theory of two kinds of nerve assumes. What happens is that the nerve as carrier of the neural function implements an inner perception of the particular metabolic process that underlies the will—in exactly the same way that the sensory nerve implements perception of what is coming to pass within the sense-organ. Unless and until neurological theory begins to operate in this domain with clear concepts, no satisfactory co-ordination of psychic and somatic life can come about.

Federica,

I know you didn't share this with the intention of restarting the discussion, but there is still something I want to comment on that grabs my attention now, just as it did before in a different lecture context.

I think it is helpful to consider what the phrase "unbiased observation" might imply here. Most readers would probably take that to mean something like: if we carefully study the receding images within the focal plane, without adding theoretical assumptions, preferences, prejudices, and so on, it will eventually become evident to the reasoning mind that the distinction between sensory and motor nerves does not exist. We will arrive at the "clear concepts" that he refers to. All the findings based on neural sections, the pathological elimination of certain nerves, and so on, will be shown to prove the opposite of what the physiologists and anatomists imagine. The 'secure anchoring' of the distinction in contemporary physiological ideas will then evaporate.

Yet is that what Steiner is truly implying here? Can we ever observe and assemble our receding mental images within the focal plane in such a way that verifies the "nerve as the carrier of the neural function that implements an inner perception of the particular metabolic process that underlies the will?" What exactly is the "inner perception of a particular metabolic process" in the context of ordinary empirical observation? As Steiner commented previously in the lecture, the neural function at issue is something that can never be perceived within the focal plane, i.e., with our ordinary consciousness. He states later that the metabolic process is one we remain completely asleep to, without higher cognition. And as he stated at the beginning, he aims to "place on record the results of a systematic spiritual investigation extending over a period of thirty years."

We can take a simple phenomenological example, such as looking at a uniformly white wall with our eyes and moving our gaze across it. It is clearly the case that we experience a distinction between receiving the impressions of the white color pixels and corresponding mental images, on the one hand, and intending to move our gaze across the wall and activating our eyeballs, on the other. At the same time, these two are closely related, since as we move our gaze across the wall, the color pixels subtly change, even if we don't notice it because of the uniform color. And if our gaze happens to cross a surprising patch of green as we progress our vision across the wall, we will probably move our eyes back toward it. In that sense, the movement of our eyeballs (or any limbs) is tightly linked with the process of perception and vice versa.

All of what Steiner is speaking about here makes more sense, from my perspective, if he is saying that this tight link points to a more unified experience of active perception at the Imaginative scale of steering. In other words, the process of perceiving living imaginations is, at the same time, an act of will that finds its physical correlate in metabolic processes of our eyes and limbs. That is also the case when we perceive our deadened perceptions and ideas, but because the relationship is so out-of-phase, we experience it much more distinctly. It feels like many impressions impinge upon our consciousness while we remain completely passive. We are completely insensitive to the fact that our eyes are constantly moving and the color pixels are correspondingly changing. That experiential distinction also finds its physical reflection in the differentiation of motor and sensory nerves within the eyeballs, which apparently serve different functions.

So why does Steiner keep insisting that this differentiation does not exist? That makes great sense if the primary concern is that the materialistic ideas attached to this differentiation serve to reinforce the habitual thinking that strives to understand the physiological relations by exclusively observing within the focal plane, as if it were a self-contained spectrum where all the relevant 'causal mechanisms' can be found. When understanding of the phenomenal facts is pursued in that way, it will naturally lead to erecting the entire psychic life on the foundations of the body, as the latter can be encompassed and observed within the focal plane. Then there can be absolutely no "unbiased observation", "clear concepts", or "satisfactory co-ordination of psychic and somatic life". All those things can only come about by expanding cognitive life through the focal plane into the volumetric dome of spiritual relations.

[Federica]

I think it is helpful to consider what the phrase "unbiased observation" might imply here. Most readers would probably take that to mean something like: if we carefully study the receding images within the focal plane, without adding theoretical assumptions, preferences, prejudices, and so on, it will eventually become evident to the reasoning mind that the distinction between sensory and motor nerves does not exist. We will arrive at the "clear concepts" that he refers to. All the findings based on neural sections, the pathological elimination of certain nerves, and so on, will be shown to prove the opposite of what the physiologists and anatomists imagine. The 'secure anchoring' of the distinction in contemporary physiological ideas will then evaporate.

Yet is that what Steiner is truly implying here? Can we ever observe and assemble our receding mental images within the focal plane in such a way that verifies the "nerve as the carrier of the neural function that implements an inner perception of the particular metabolic process that underlies the will?" What exactly is the "inner perception of a particular metabolic process" in the context of ordinary empirical observation? As Steiner commented previously in the lecture, the neural function at issue is something that can never be perceived within the focal plane, i.e., with our ordinary consciousness. He states later that the metabolic process is one we remain completely asleep to, without higher cognition.

Thanks for your input, Ashvin. Yes, exactly as you say (bolded). I wrote above: Steiner considers that nervous activity proper (the correlate of ideation/representation) "cannot possibly be an object of physiologically empirical observation". What you point to here is part of what I intended to convey. For Steiner, nerve activity proper can't be perceived in ordinary cognition. I wanted to highlight that, because I don't think it came out of our discussion last year. "Proper" is key here, however, as I will try to illustrate in relation to the second part of your post.

This impossibility of perceiving neural activity on the focal plane is one of the "new concepts" science needs to somehow integrate. Otherwise, if we focus on so-called motor nerves and sensory nerves differences, we imply that we can capture nerve function by contemplating the receding images of the physical nerves and their behavior, but for Steiner that's intrinsically impossible. So the first new concept is that neurological findings can't demonstrate anything about nerve function proper.

However, what those findings can speak of are the secondary functions that take place in the nerves, yet don't constitute neural function proper. This happens because all three somatic functions happen everywhere in the body. So, in the nerves take place not only neural processes proper, but also metabolic and rhythmic processes. And these actually can be contemplated within the receding images. These are unconscious and semi-unconscious processes, but their correlates can still be observed in experiments. We can even say that for Steiner all that we can ever observe in nerves - the connecting electrical impulses and so on - are nothing other than metabolic (and rhythmic) activity, not neural activity.

We can take a simple phenomenological example, such as looking at a uniformly white wall with our eyes and moving our gaze across it. It is clearly the case that we experience a distinction between receiving the impressions of the white color pixels and corresponding mental images, on the one hand, and intending to move our gaze across the wall and activating our eyeballs, on the other. At the same time, these two are closely related, since as we move our gaze across the wall, the color pixels subtly change, even if we don't notice it because of the uniform color. And if our gaze happens to cross a surprising patch of green as we progress our vision across the wall, we will probably move our eyes back toward it. In that sense, the movement of our eyeballs (or any limbs) is tightly linked with the process of perception and vice versa.

All of what Steiner is speaking about here makes more sense, from my perspective, if he is saying that this tight link points to a more unified experience of active perception at the Imaginative scale of steering. In other words, the process of perceiving living imaginations is, at the same time, an act of will that finds its physical correlate in metabolic processes of our eyes and limbs. That is also the case when we perceive our deadened perceptions and ideas, but because the relationship is so out-of-phase, we experience it much more distinctly. It feels like many impressions impinge upon our consciousness while we remain completely passive. We are completely insensitive to the fact that our eyes are constantly moving and the color pixels are correspondingly changing. That experiential distinction also finds its physical reflection in the differentiation of motor and sensory nerves within the eyeballs, which apparently serve different functions.

So why does Steiner keep insisting that this differentiation does not exist? That makes great sense if the primary concern is that the materialistic ideas attached to this differentiation serve to reinforce the habitual thinking that strives to understand the physiological relations by exclusively observing within the focal plane, as if it were a self-contained spectrum where all the relevant 'causal mechanisms' can be found. When understanding of the phenomenal facts is pursued in that way, it will naturally lead to erecting the entire psychic life on the foundations of the body, as the latter can be encompassed and observed within the focal plane. Then there can be absolutely no "unbiased observation", "clear concepts", or "satisfactory co-ordination of psychic and somatic life". All those things can only come about by expanding cognitive life through the focal plane into the volumetric dome of spiritual relations.

I think this is an ingenious reading, but it doesn't take into account the whole picture. We have to put ourselves in Steiner’s shoes, in that phase of applied development of spiritual science - the last years of his life. Namely, he is not trying to speak a veiled language, implying that his points can only be really understood if we abandon the focal plane and put ourselves in the perspective of higher cognition. On the contrary, he is continually referring to physiological material. He wants to trace - starting from the soul - its correlates toward the physical. He speaks to scientists and doctors. His intention is to bridge spiritual and natural science. He says: “It is fully possible to substantiate these results with the scientific means available today.” He says he is “seeking the relation of the soul element to the bodily element”, seeking to bring clarity to bodily will. In this pursuit, as we noted, neural activity is the 'odd one', with regards to which “anatomy and physiology must arrive at the knowledge that they can discover nerve activity only through a method of exclusion” that is indirectly. However, will correlates and feeling correlates are perceivable directly in the physical body. His major concern in all this is to debunk the scientific prejudice that all soul activity is nerve activity. He absolutely wants to show that only perceiving and mental picturing have their basis in the nerves, but not willing, nor feeling. Getting this understanding straight is absolutely crucial for pathology and therapy, because if we suppose that all soul events manifest in the body through the nerves, and only through the nerves, we make it impossible to gain true understanding of any illnesses whatsoever. This is what he ultimately has in mind and is super concerned about. For example, in GA 312 (same period) he deconstructs the common, failed belief that hysteria is a nervous condition. He shows how it is instead a metabolic condition, and how in turn a hysterical predisposition is the real foundation for the development of tuberculosis. This is only one of countless examples that revolutionize medical understanding, to put it straight.

Now, if we believe in sensory nerves and motor nerves, we believe that nerve function is observable and differentiable in the nerves (which is not, as we have noted) and we have to mistakenly connect will, perception, mental picturing, and emotions too, to the nerves. The entire soul volume becomes, in the body, a matter of nerve activity! And that’s how we get all understanding of disease processes completely upside down, with zero cues on how to derive any therapeutic guidelines from pathology. Therapy was a completely tentative endeavor at his times (and today too) deprived of any logic and connection with pathology. Steiner absolutely wants to restore some rational understanding to the entire domain. Understanding how illness arises must at the same time give us insights on how to cure it!

These are the bigger questions he works with in those years. He has therefore in mind to trace and clarify the very physical implications of soul activity so that science, medicine, and psychology can advance. In the same years, he gives the medical lectures - in which he references “Riddles of the soul”. These cycles - especially GA 312 - are instructive to get a more dimensional sense of his overall line of work and views on nerves. In this sense, in the "Riddles of the Soul" quotes above, he is not laying the foundations of the nature of man and the interconnectedness of the sensible and the supersensible for esoteric students. Rather, he is speaking as concretely and materially as possible, with spiritual scientific applications at hand. However, as we said, when it comes to just nervous activity proper, this is not possible. Just nervous activity is not directly experienceable other than in higher cognition.

Steiner argues that motor nerves do not exist because it’s absolutely necessary that the life of will is recognized as autonomous, and independent of neural activity proper. “A realistic insight into physiological findings shows that willing as such must not be brought into relation to nerve processes but rather to metabolic processes.” This "realistic insight" means accepting that metabolic activities take place everywhere, including in the nerves, while proper neural activity is not perceivable through natural experiments. So, physiological findings must be read in this manner. Steiner says (paraphrased), the working will that permeates nerves (we call it motor nerves) must be seen as a bodily metabolic activity. In this very concrete sense he means that motor nerves do not exist. What we call so is simply metabolism taking place in neural location, not neural activity proper. In the same way, what we gather from experiments on sensory nerves, is also metabolic activity, not perceptual-representational activity. At the same time, neural function proper (perceptual activity, oriented inwardly or outwardly) takes place in all nerves, but remains unseen to natural scientific inquiry.

In other words, will permeates the nerves. We like to call that motor nerves. But the conceptual framework that we build in this way prevents a genuine understanding of man, fruitful for the evolution of the sciences. Thus we have to conceptualize the will-permeated nerves as an expression of metabolism (with all that this implies, in terms of what metabolic processes are and do). Further, we have to conceptualize will-permeated organs as metabolism in process, whatever the organ is, nerves or other. This, Steiner means, is the healthy conceptual foundation we need to create, for the sciences to progress into the future.

[AshvinP]

Thanks for your input, Ashvin. Yes, exactly as you say (bolded). I wrote above: Steiner considers that nervous activity proper (the correlate of ideation/representation) "cannot possibly be an object of physiologically empirical observation". What you point to here is part of what I intended to convey. For Steiner, nerve activity proper can't be perceived in ordinary cognition. I wanted to highlight that, because I don't think it came out of our discussion last year. "Proper" is key here, however, as I will try to illustrate in relation to the second part of your post.

This impossibility of perceiving neural activity on the focal plane is one of the "new concepts" science needs to somehow integrate. Otherwise, if we focus on so-called motor nerves and sensory nerves differences, we imply that we can capture nerve function by contemplating the receding images of the physical nerves and their behavior, but for Steiner that's intrinsically impossible. So the first new concept is that neurological findings can't demonstrate anything about nerve function proper.

However, what those findings can speak of are the secondary functions that take place in the nerves, yet don't constitute neural function proper. This happens because all three somatic functions happen everywhere in the body. So, in the nerves take place not only neural processes proper, but also metabolic and rhythmic processes. And these actually can be contemplated within the receding images. These are unconscious and semi-unconscious processes, but their correlates can still be observed in experiments. We can even say that for Steiner all that we can ever observe in nerves - the connecting electrical impulses and so on - are nothing other than metabolic (and rhythmic) activity, not neural activity.

We can take a simple phenomenological example, such as looking at a uniformly white wall with our eyes and moving our gaze across it. It is clearly the case that we experience a distinction between receiving the impressions of the white color pixels and corresponding mental images, on the one hand, and intending to move our gaze across the wall and activating our eyeballs, on the other. At the same time, these two are closely related, since as we move our gaze across the wall, the color pixels subtly change, even if we don't notice it because of the uniform color. And if our gaze happens to cross a surprising patch of green as we progress our vision across the wall, we will probably move our eyes back toward it. In that sense, the movement of our eyeballs (or any limbs) is tightly linked with the process of perception and vice versa.

All of what Steiner is speaking about here makes more sense, from my perspective, if he is saying that this tight link points to a more unified experience of active perception at the Imaginative scale of steering. In other words, the process of perceiving living imaginations is, at the same time, an act of will that finds its physical correlate in metabolic processes of our eyes and limbs. That is also the case when we perceive our deadened perceptions and ideas, but because the relationship is so out-of-phase, we experience it much more distinctly. It feels like many impressions impinge upon our consciousness while we remain completely passive. We are completely insensitive to the fact that our eyes are constantly moving and the color pixels are correspondingly changing. That experiential distinction also finds its physical reflection in the differentiation of motor and sensory nerves within the eyeballs, which apparently serve different functions.

So why does Steiner keep insisting that this differentiation does not exist? That makes great sense if the primary concern is that the materialistic ideas attached to this differentiation serve to reinforce the habitual thinking that strives to understand the physiological relations by exclusively observing within the focal plane, as if it were a self-contained spectrum where all the relevant 'causal mechanisms' can be found. When understanding of the phenomenal facts is pursued in that way, it will naturally lead to erecting the entire psychic life on the foundations of the body, as the latter can be encompassed and observed within the focal plane. Then there can be absolutely no "unbiased observation", "clear concepts", or "satisfactory co-ordination of psychic and somatic life". All those things can only come about by expanding cognitive life through the focal plane into the volumetric dome of spiritual relations.

I think this is an ingenious reading, but it doesn't take into account the whole picture. We have to put ourselves in Steiner’s shoes, in that phase of applied development of spiritual science - the last years of his life. Namely, he is not trying to speak a veiled language, implying that his points can only be really understood if we abandon the focal plane and put ourselves in the perspective of higher cognition. On the contrary, he is continually referring to physiological material. He wants to trace - starting from the soul - its correlates toward the physical. He speaks to scientists and doctors. His intention is to bridge spiritual and natural science. He says: “It is fully possible to substantiate these results with the scientific means available today.” He says he is “seeking the relation of the soul element to the bodily element”, seeking to bring clarity to bodily will. In this pursuit, as we noted, neural activity is the 'odd one', with regards to which “anatomy and physiology must arrive at the knowledge that they can discover nerve activity only through a method of exclusion” that is indirectly. However, will correlates and feeling correlates are perceivable directly in the physical body. His major concern in all this is to debunk the scientific prejudice that all soul activity is nerve activity. He absolutely wants to show that only perceiving and mental picturing have their basis in the nerves, but not willing, nor feeling. Getting this understanding straight is absolutely crucial for pathology and therapy, because if we suppose that all soul events manifest in the body through the nerves, and only through the nerves, we make it impossible to gain true understanding of any illnesses whatsoever. This is what he ultimately has in mind and is super concerned about. For example, in GA 312 (same period) he deconstructs the common, failed belief that hysteria is a nervous condition. He shows how it is instead a metabolic condition, and how in turn a hysterical predisposition is the real foundation for the development of tuberculosis. This is only one of countless examples that revolutionize medical understanding, to put it straight.

Now, if we believe in sensory nerves and motor nerves, we believe that nerve function is observable and differentiable in the nerves (which is not, as we have noted) and we have to mistakenly connect will, perception, mental picturing, and emotions too, to the nerves. The entire soul volume becomes, in the body, a matter of nerve activity! And that’s how we get all understanding of disease processes completely upside down, with zero cues on how to derive any therapeutic guidelines from pathology. Therapy was a completely tentative endeavor at his times (and today too) deprived of any logic and connection with pathology. Steiner absolutely wants to restore some rational understanding to the entire domain. Understanding how illness arises must at the same time give us insights on how to cure it!

These are the bigger questions he works with in those years. He has therefore in mind to trace and clarify the very physical implications of soul activity so that science, medicine, and psychology can advance. In the same years, he gives the medical lectures - in which he references “Riddles of the soul”. These cycles - especially GA 312 - are instructive to get a more dimensional sense of his overall line of work and views on nerves. In this sense, in the "Riddles of the Soul" quotes above, he is not laying the foundations of the nature of man and the interconnectedness of the sensible and the supersensible for esoteric students. Rather, he is speaking as concretely and materially as possible, with spiritual scientific applications at hand. However, as we said, when it comes to just nervous activity proper, this is not possible. Just nervous activity is not directly experienceable other than in higher cognition.

Steiner argues that motor nerves do not exist because it’s absolutely necessary that the life of will is recognized as autonomous, and independent of neural activity proper. “A realistic insight into physiological findings shows that willing as such must not be brought into relation to nerve processes but rather to metabolic processes.” This "realistic insight" means accepting that metabolic activities take place everywhere, including in the nerves, while proper neural activity is not perceivable through natural experiments. So, physiological findings must be read in this manner. Steiner says (paraphrased), the working will that permeates nerves (we call it motor nerves) must be seen as a bodily metabolic activity. In this very concrete sense he means that motor nerves do not exist. What we call so is simply metabolism taking place in neural location, not neural activity proper. In the same way, what we gather from experiments on sensory nerves, is also metabolic activity, not perceptual-representational activity. At the same time, neural function proper (perceptual activity, oriented inwardly or outwardly) takes place in all nerves, but remains unseen to natural scientific inquiry.

In other words, will permeates the nerves. We like to call that motor nerves. But the conceptual framework that we build in this way prevents a genuine understanding of man, fruitful for the evolution of the sciences. Thus we have to conceptualize the will-permeated nerves as an expression of metabolism (with all that this implies, in terms of what metabolic processes are and do). Further, we have to conceptualize will-permeated organs as metabolism in process, whatever the organ is, nerves or other. This, Steiner means, is the healthy conceptual foundation we need to create, for the sciences to progress into the future.

Thanks, Federica. I'm glad you provided this wider context of Steiner's general aim, with numerous examples, and I completely agree with the context you have described. There are tremendous implications if we mistakenly attribute the entire soul life to what can be observed as 'nerve activity' within the focal plane. At the end of the day, everything we discuss on the forum, whether in terms of a strict phenomenology of spiritual activity or in terms of understanding specific spiritual scientific revelations, revolves around shifting our perspective so that we become more sensitive to how the images within the focal plane testify to constraints that can only be spiritually known. That was Steiner's goal as well - it was not so much about describing the spiritual-somatic correspondences of the soul life and encapsulating them within a framework that we can rely upon indefinitely, but about helping his listeners and readers transform their soul lives by moving their imagination in unfamiliar ways and becoming more sensitive to how their imaginative flow fits within the overlapping constraints.

Then it becomes a question of honing in on how exactly that can be done, where there may be a few differences between us. As I see it, the more we imagine it is possible to attain the 'healthy conceptual foundation' through observations and reasoning confined to the focal plane, i.e., without the perspective shift mentioned above, the more we will be tempted to rely on that confined perspective for our spiritual understanding and for communications to others. I think this is exactly the danger that Steiner is generally warning us about in many places - he is saying the bridge between natural and spiritual science can never be found by extrapolating our familiar focal plane gestures further and further, in more and more 'clever' ways, such that we suddenly arrive at the 'realistic insights' he is referring to. Those insights can only be accommodated with a new cognitive perspective and gestures. With the latter, we can then see how the modern scientific research testifies to what is independently investigated through higher cognition. But for that testimonial experience to take root, the 'tipping point' in our thinking perspective must be reached.

In that respect, we should also keep in mind what was previously discussed regarding the significant degeneration of the intellectual soul since Steiner's time, due to excessive conditioning by sensory and sub-sensory influences. What could be accomplished in terms of attaining 'healthy understanding' through focal plane reasoning in Steiner's time is therefore a much more remote possibility in our time. In a certain sense, the modern intellectual soul has been thoroughly refashioned in the shape of its previous theories since the 19th century. Its entire content of imagination, feeling, and volition is closely shaped by sensory-constrained mental images. The average soul only experiences itself thinking, feeling, and willing what is intuitively compatible with that myopic set of pictures. In that sense, the conscious soul life is quite fully determined by the nervous system that is tied to mental picturing. That only further reinforces the tendency of the people who study these things to interpret the experiments they conduct and the facts they observe as supporting this reductive understanding. Steiner has pointed to this in various places as well, for example:

https://rsarchive.org/Lectures/GA204/En ... 02p01.html
"What is the cause of this? It is in fact this: We have the soul-spirit being of man; we bear it within us. This soul-spirit being is the creator of the entire form of man's organism. It is therefore not surprising that here in the most complete and perfect part of the organism, namely the nervous system of the brain, the replica created by the soul-spirit being resembles the latter in every way. It is indeed true that in the place where man is most of all man, so to speak, namely in the structure of his nerves, he is a faithful replica of the soul-spiritual element. Thus, a person who, in the first place, must always have something the senses can perceive and is content with the replica, actually perceives in the copy the very same thing that is seen in the soul-spiritual original. Having no desire for soul and spirit and only concentrating, as it were, on the replica, he stops short at the structure of the brain. Since this structure of the brain presented itself in such remarkable perfection to the observer of the mid-nineteenth century, and considering the predisposition of humanity at that time, it was extraordinarily easy to develop theoretical materialism."

Within the focal plane, the differentiation between sensory and motor nerves certainly exists. Even if we say what we observe in their functioning is always traced to metabolic activity, there must be some differentiation between how that metabolism unfolds in what we call "sensory nerves" compared to how it unfolds in what we call "motor nerves". These form a quite obvious polarity within the focal plane, as further demonstrated by relevant experiments that we have discussed. Steiner says it is a distinction between perceiving will impulses in the external world as they permeate the 'inlets' of the sensory organs (sensory), and perceiving impulses within our organism as they flow back out into the world (motor). I see no issue with characterizing it this way, as long as we understand that "perceiving impulses within our organism" is something that can only be verified from the Imaginative perspective and, within the focal-intellectual plane, can also be characterized as "activating the muscles". We should keep in mind that the "mental picturing" associated with impulses within the organism unfolds entirely beneath the threshold of consciousness, unlike the mental picturing associated with impulses from the external world that come through the senses (which can be potentially recalled through our focal plane gestures).

"The body, within its own field, affords participation in its external world in two directions, in sensuous happenings and in motor happenings; and so does the spirit—in so far as that experiences the representations of the psyche imaginally (even in ordinary consciousness) from the one direction, while in the other—in willing—it in-forms the intuitive impulses that are realising themselves through metabolic processes."

Recognizing this polar differentiation by itself does not force us to connect will and feeling to the nerves, in the sense that we are forced to conclude the former are fully determined by the latter and have no relationship to the rhythmic and metabolic activities. It is precisely the conceptual framework that we erect on top of this observation, which is rooted in default thinking habits of seeking encompassing 'causal explanations', mechanisms, and so forth within the focal plane, that leads in this perilous direction, as you point out. These are all the common traps that Cleric has phenomenologically illustrated in recent essays, and the only way to avoid them is to intimately experience their existence and how they take shape within our imaginative flow. I can see no other way in which the 'healthy conceptual foundation' for the natural sciences can be attained and advanced further.  

PS - I asked Google AI to summarize the current research on differences and similarities between efferent and afferent nerves. Here is the link for anyone interested - https://share.google/aimode/3cXGkU9HEyPKVskSQ