There is a gulf between what we know and what we can prove to another.

We know only sensations and our awareness itself, though these are not 'provable'.

The need to prove them relies in some sense on the assumption that there are other minds, and or an external universe (ie independent of our mind), and so the need to prove what we know is in some sense based on circular reasoning.

Bridgman was a phenomenalist in that he knew that he knew only what was in his awareness and everything else was only assumed, and that one knows the meaning of what is in one's mind, but that science/physics if defined as being an activity 'in the public sphere' needs to be based on what one can prove, and that meanings in order to be accessible to others, to be public, need to be based on operations.

Eddington is of course well aware of all this but assumes that there are indeed other minds and that these minds understand intuitively or internally just as does his own mind and so he can talk of sensations and feelings and convey meanings by appealing to/utilizing that fundamental similarity.

What we know are sensations(or perhaps Whitehead's "processes" etc), the sensations can be of pointers on measurement machines as part of experiments which give rise to interpretations like 'an electron was just here" but we do not know electrons or machines we know sensations, the sensation we call "I see a machine", the sensation we call "I am contemplating the set of properties we associate to the notion of an electron" etc, rather than knowing "an electron" (which may or may not "exist).

Bridgman and Eddington

Two eminent physicists, contemporaries of Einstein, whose words take addiitonal weight since they were both keenly involved in experiment not only theory. Both lectured and wrote books about the fundamentals of the physical universe, one titled "The Nature of the Physical World" (Eddington, 1928), and the other, a few years later, very similarly titled "The Nature of Physical Theory" (Bridgman, 1935-6), following his ealier The Logic of Modern Physics, in1927.

Given their authors and the titles one understands that these are meant not as philosophical musings or metaphysics but rather to convey a physicists view of what we can know, though they both contain what others will conside rmetaphysics - and in this proposed study we are interested in exatly this divide, between those who feel that the topic does not belong under the category of "what we can know" but rather of "metaphysical speculations"..... [Eddington's book is based on hs Gifford lectures, which by definition have a religious or metaphysical slant, but he is presenting ideas that as a physicist he feels are based on what is known, not on his personal religious beliefs.]

One imagines Bridgman was familiar with the works of Eddington, especially as Eddington wrote the first book introducing Einstein's technical presentaiton of General Relativity to the wider physics community, and Bridgman was very influenced by Einstein's theories, and so the similarity of the titles may not be coincidence, and indeed Bridgman's work may have been a conscious effort to respond to Eddington's, though both titles are probably adapted from a rather prior work whose contents must have been know to both: "De rerum natura = "On the Nature of Things" a book on science (written as a poem) by the Roman poet and philosopher Lucretius more than 2,000 years ago (but only re-desicovered a few hundred years ago).

In both books one senses that physics is not so much "a description of the universe" as it is "a construction of the human brain" and so is inherently limited by what the brain can comprehend, what it perceives, how it organizes data, and is necessarily shaped by the brains capabilites and structure etc. As such, it is certainly necesary to understand the human brain in order to understand how the models it contructs of "reality" may or may not conform to "actual reality", or to use a more defined notion, to the reality as constructed by an alien brain of quite different structure and processing etc.

The proposed experiment, in that it attempts to discover some aspect of the brain related to our most basic knowledge of the universe, may have some relevance to this issue.

Excerpts from Eddington and Bridgman

Why I present the views of Eddington and Bridgman:

Percy Bridgman 1946 Nobel Prize in Physics, as the excerpt below indicates, had an exceptionally keen understanding of the difference between physically meaningful sentences and those that are not, and a professional obsession with carfully defining what can and cannot be known, and so cannot in any sense be dismissed as a sloppy thinker or wide-eyed naive speculator, despite all this, his words in the immediately-following paragraphs indicate that he clearly considers independent automatic self-knowledge of awareness to be not only possible but considers awareness to be the only known existent at its level.

The excerpt from Eddington indicates the same.

Percy Bridgman

"This position, which I suppose is the solipsist position, is often felt to be absurd and contrary to common sense. How it is asked, can there be agreement as to experience unless there are external things which both you and I perceive? Part of the hostility to the solipsist position is, I think, merely due to confusion of thinking, and there is a strong element of the pseudo-problem mixed up here. If I say that an external thing is merely part of my direct experience to which I find that you react in certain ways, what more is there to be said, or indeed what other operational meaning can be attached to the concept of an external thing? It seems to me that as I have stated it, the solipsist position, if this is indeed the solipsist position, is a simple statement of what direct observation gives me, and we have got to adjust our thinking so that it will not seem repugnant.

Bridgman is writing as a very careful experimentalist, trying to overcome the reasons which led pre-SR physicsits to make mistakes which were due to what seemed to be reasonable ways of doing things but which Einstein through careful consideration showed actually involved assumptions. So when he talks of solipsisn it is because it is the scenario with the fewest assumptions and therefore the most reasonable for an experimental physicist - he proceeds with great logical rigor, and so this type of consideration is purely physics not philosophy or metaphysics. It seems obvious to me that Bridgman's statement of solipsism seems to imply that he is taking the existence of mind as fact, and also espousing the views of the idealists in stating that it is only via mind that one knows anyhting else, and that indeed it is the existence of everything else which is not really known only assumed. Physics operated exactly in that realm of the "assumed to exist", and only because it is known to mind, and in the way it is known to mind, so tha tthe view of the careful operaitonalist is actually directly opposite to that of the naturalist physicist who knows only of that which is assumed to Bridgman and negates the possibility of the existence of that which is the only phenomenon known to Bridgman to exist.

Clearly this is a matter which should be of relevance to physicists, even if by consensus it is excluded from physics - excpt that most physicists ignore it, since dealing with it is a waste of time for a professional physicsit since either they are of those who know mind exists but also that it cannot be proven and no equaiotns or experiemtns proposed. or they know it cannot exist and so why bother with discussing it.

The Logic of Modern Physics is a 1927 philosophy of science book by American physicist and Nobel laureate Percy Williams Bridgman. The book was widely read by scholars in the social sciences, in which it had a huge influence in the 1930s and 1940s,^[1] and its major influence on the field of psychology in particular surpassed even that on methodology in physics, for which it was originally intended.^[2] The book is notable for explicitly identifying, analyzing, and explaining operationalism for the first time,^[3] and coining the term operational definition.

Operationalism can be considered a variation on the positivist theme, and, arguably, a very powerful and influential one.^[1] Sir Arthur Eddington^[4] had discussed notions similar to operationalization before Bridgman, and pragmatic philosophers^[5] had also advanced solutions to the related ontological problems. Bridgman's formulation, however, became the most influential.^[2]

See below an excerpt from his book "The Nature of Physical Theory":

"The Logic of Modern Physics"

Introduction: One of the most noteworthy movements in recent physics is a change of attitude toward what may be called the interpretative aspect of physics. It is being increasingly recognised, both in the writings and the conversation of physicists, that the world of experiment is not understandable without some examination of the purpose of physics and of the nature of its fundamental concepts. It is no new thing to attempt a more critical understanding of the nature of physics, but until recently all such attempts have been regarded with a certain suspicion or even sometimes contempt. The average physicist is likely to deprecate his own concern with such questions, and is inclined to dismiss the speculations of fellow physicists with the epithet "metaphysical." This attitude has no doubt had a certain justification in the utter unintelligibility to the physicist of many metaphysical speculations and the sterility of such speculations in yielding physical results. However, the growing reaction favouring a better understanding of the interpretative fundamentals of physics is not a pendulum swing of the fashion of thought toward metaphysics, originating in the upheaval of moral values produced by the great war, or anything of the sort, but is a reaction absolutely forced upon us by a rapidly increasing array of cold experimental facts.

This reaction, or rather new movement, was without doubt initiated by the restricted theory of relativity of Einstein.......

...that experiment compels a critique of much more than the concepts of space and time is made increasingly evident by all the new facts being discovered in the quantum realm.

..

Certain limitations will have to be set to our inquiry in order to keep it within manageable compass. It is of course the merest truism that all our experimental knowledge and our understanding of nature is impossible and non-existent apart from our own mental processes, so that strictly speaking no aspect of psychology or epistemology is without pertinence. Fortunately we shall be able to get along with a more or less naive attitude toward many of these matters. We shall accept as significant our common sense judgment that there is a world external to us, and shall limit as far as possible our inquiry to the behaviour and interpretation of this "external" world. We shall rule out inquiries into our states of consciousness as such. In spite, however, of the best intentions, we shall not be able to eliminate completely considerations savouring of the metaphysical, because it is evident that the nature of our thinking mechanism essentially colours any picture that we can form of nature, and we shall have to recognise that unavoidable characteristics of any outlook of ours are imposed in this way.

.OPERATIONALISM: "To find the length of an object, we have to perform certain physical operations. The concept of length is therefore fixed when the operations by which length is measured are fixed: that is, the concept of length involves as much as and nothing more than the set of operations by which length is determined. In general, we mean by any concept nothing more than a set of operations; the concept is synonymous with a corresponding set of operations. "

SIR ARTHUR STANLEY EDDINGTON

Eddington, in "The Mathematical theory of Relativity" 1924" wrote (in the Introduction ) "“A physical quantity is defined by the series of operations and calculations of which it is the result.” This view was further developed by Bridgman into what is called "operationalism". One can assume Bridgman was very familiar with the writings of Eddington [see eg Mary Hesse: "Arthur Eddington, whose metaphysical musings about physics Bridgman took a strong exception to" quoted in https://plato.stanford.edu/entries/operationalism/].

The similar preoccupation with definition via operations, and the similarity in title of Bridgman's book to the one written by Eddington a few years earlier hints that perhaps Bridgman's is written in somewhat of an homage (and perhaps counter) to Eddington's.

And though to a mystically-inclined physicist the book of Bridgman might seem dry, to a naturalist perhaps Bridgman's book is mystical, viz his comment basically assuming the inevitable unshakeable truth behind solipsism (whether one acts in accordiance with its implications or not - if one takes into account the fact that we do not seem to be in control of what we exeperience then solipsism will not affect our choices of how to act). (see below) And in this Bridgmana and Eddington are united.

In my judgement they seem firmly on the same side in the context of this paper, ie opposite that of the naturalists. However, there is an assumption in my statement which I wish to check: since Eddington is openly enfranchising of the "mysterious" etc whereas Bridgman is completely not, it may be that even naturalists agree with Bridgman's idea of solipsism as the minimalistic truth about our reality; I do not wish to simply make the assumption that solipsism is incomprehensible to materilaists/naturalists and so I pose this as a quesiton in the survay.

Eddington also is very concerned with rigor, and his idea of the seaman's net ... shows his preoccupation with avoiding unwaranted assumptions, as does his championing of operationalism (a name given to these ideas only later), but he in some sense is also concerned with not jettisoning the deepest of truths as long as they are truths. I believe one an make the case even regarding his presentaitons of the notion of electrons as being composed of "mindstuff" that it is meant by him to be fully a physics conclusion rather than his personal metaphysics or religion, though of course he does not write of these subjects in his professional papers published in journals (nor presumeably would they have been published had he done so).

Still, all in all, it seems to me that consciousness and its role in the creation or perception of our reality is a subject physicists must discuss - as physicists - albeit as a prelude to engaging in physics, as Bridgman does, rather than as part of physics itself since it deals with that which cannot be proven to exist. However, perhaps not, since some physicists do NOT see consciousness in the same way. On the other hand, shouldn't students who are not aware of the entire complicated issue be exposed to it in pre-science class, so that those who are not naturalists/materialists (though they don't yet know these terms) can gain a deeper insight into the nature of their reality, and how science does or does not relate to it? And thereby to know what science can and cannot tell them about the fundamentals of their reality. And to gain an appreciation of the fact that there are different viewpoints (or different brain-wirings) on this issue, and a recognition of the differences betwen their relaity and that of fellow-students who are by nature materialists/naturalists.

Eddington clearly refers to something qualitatively other than what naturalists consider, and also assumes that everyone agrees it is known directly, though he seems to agree that its existence cannot be proven to another.

The existence of naturalists however means that it is NOT true that all agree that there is some phenomenon which is known directly and is qualitatively other than "matter".

Eddington: "THE NATURE OF THE PHYSICAL WORLD"

To put the conclusion crudely⎯the stuff of the world is mind-stuff. As is often the way with crude statements, I shall have to explain that by “mind” I do not here exactly mean mind and by “stuff” I do not at all mean stuff. Still this is about as near as we can get to the idea in a simple phrase. The mind-stuff of the world is, of course, something more general than our individual conscious minds; but we may think of its nature as not altogether foreign to the feelings in our consciousness.

The realistic matter and fields of force of former physical theory are altogether irrelevant⎯except in so far as the mind-stuff has itself spun these imaginings. The symbolic matter and fields of force of present-day theory are more relevant, but they bear to it the same relation that the bursar’s accounts bear to the activity of the college.

Having granted this, the mental activity of the part of the world constituting ourselves occasions no surprise; it is known to us by direct self-knowledge, and we do not explain it away as something other than we know it to be⎯or, rather, knows itself to be. It is the physical aspects of the world that we have to explain, presumably by some such method as that set forth in our discussion of world-building. Our bodies are more mysterious than our minds⎯at least they would be, only that we can set the mystery on one side by the device of the cyclic scheme of

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physics, which enables us to study their phenomenal behaviour without ever coming to grips with the underlying mystery. The mind-stuff is not spread out in space and time; these are part of the cyclic scheme ultimately derived out of it. But we must presume that in some other way or aspect it can be differentiated into parts.

Only here and there does it rise to the level of consciousness, but from such islands proceeds all knowledge. Besides the direct knowledge contained in each self-knowing unit, there is inferential knowledge. The latter includes our knowledge of the physical world. It is necessary to keep reminding ourselves that all knowledge of our environment from which the world of physics is constructed, has entered in the form of messages transmitted along the nerves to the seat of consciousness.

Obviously the messages travel in code. When messages relating to a table are traveling in the nerves, the nerve-disturbance does not in the least resemble either the external table that originates the mental impression or the conception of the table that arises in consciousness.* In the central clearing station the incoming messages are sorted and decoded, partly by instinctive image-building inherited from the experience of our ancestors, partly by scientific comparison and reasoning.

By this very indirect and hypothetical inference all our supposed acquaintance with and our theories of a world outside us have been built up. We are acquainted with an external world because its fibers run into our consciousness; it is only our own ends of the fibers that we know; from those ends we more or less successfully reconstruct the rest, as a paleontologist reconstructs an extinct monster from its footprint. * I mean, resemble in intrinsic nature.

It is true (as Bertrand Russell has emphasized) that the symbolic description of structure will be identical for the table in the external world and for the conception of the table in consciousness if the conception is scientifically correct. If the physicist does not attempt to penetrate beneath the structure he is indifferent as to which of the two we imagine ourselves to be discussing.

The mind-stuff is the aggregation of relations and relata which form the building material for the physical world. Our account of the building process shows, however, that much that is implied in the relations is dropped as unserviceable for the required building. Our view is practically that urged in 1875 by W. K. Clifford⎯ “The succession of feelings which constitutes a man’s consciousness is the reality which produces in our minds the perception of the motions of his brain.” That is to say, that which the man himself knows as a succession of feelings is the reality which when probed by the appliances of an outside investigator affects their redings in such a way that it is identified as a configuration of brain-matter. Again Bertrand Russell writes⎯* What the physiologist sees when he examines a brain is in the physiologist, not in the brain he is examining. What is in the brain by the time the physiologist examines it if it is dead, I do not profess to know; but while its owner was alive, part, at least, of the contents of his brain consisted of his percepts, thoughts, and feelings. Since his brain also consisted of electrons, we are compelled to conclude that an electron is a grouping of events, and that if the electron is in a human brain, some of the events composing it are likely to be some of the “mental states” of the man to whom the brain belongs. Or, at any rate, they are likely to be parts of such “mental states” ⎯for it must not be assumed that part of a mental state must be a mental state. I do not wish to

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discuss what is meant by a “mental state;” the main point for us is that the term must include percepts. Thus a percept is an event or a group of events, each of which belongs to one or more of the groups constituting the electrons of the brain. This, I think, is the most concrete statement that can be made about electrons; everything else that can be said is more or less abstract and mathematical. I quote this partly for the sake of the remark that it must not be assumed that part of a mental state must be a mental state. We can no doubt analyse the content of consciousness during a short interval of time into more or less elementary constituent feelings; but it is not suggested that this psychological analysis will reveal the elements out of whose measure-numbers the atoms or electrons are built. The brain-matter is a partial aspect of the whole mental state; but the analysis of the brain-matter by physical investigation does not run at all parallel with the analysis of the mental state by psychological investigation.

I assume that Russell meant to warn us that, in speaking of part of a mental state, he was not limiting himself to parts that would be recognized as such psychologically, and he was admitting a more abstract kind of dissection. This might give rise to some difficulty if we were postulating complete identity of mind-stuff with consciousness. But we know that in the mind there are memories not in consciousness at the moment but capable of being summoned into consciousness. We are vaguely aware that things we cannot recall are lying somewhere about and may come into the mind at any moment. Consciousness is not sharply defined, but fades into subconsciousness; and beyond that we must postulate something indefinite but yet continuous with our mental nature. This I take to be the world-stuff. We liken it to our conscious feeling because, now that we are convinced of the formal and symbolic character of the entities of physics, there is nothing else to liken it to.

It is sometimes urged that the basal stuff of the world should be called “neutral stuff” rather than “mind-stuff,” since it is to be such that both mind and matter originate from it. If this is intended to emphasize that only limited islands of it constitute actual minds, and that even in these islands that which is known mentally is not equivalent to a complete inventory of all that may be there, I agree. In fact I should suppose that the self-knowledge of consciousness is mainly or wholly a knowledge which eludes the inventory method of description. The term “mind-stuff” might well be amended; but neutral stuff seems to be the wrong kind of amendment. It implies that we have two avenues of approach to an understanding of its nature. We have only one approach, namely through our direct knowledge of mind. The supposed approach through the physical world leads only into the cycle of physics, where we run round and round like a kitten chasing its tail and never reach the world-stuff at all. I assume that we have left the illusion of substance so far behind that the word “stuff” will not cause any apprehension. I certainly do not intend to materialize or substantialize mind. Mind is⎯but you know what mind is like, so why should I say more about its nature? The word “stuff” has reference to the function it has to perform as a basis of world-building and does not imply any modified view of its nature. It is difficult for the matter-of-fact physicist to accept the view that the substratum of everything is of mental character. But no one can deny that mind is the first and most direct thing in our experience, and all else is remote inference⎯inference either intuitive or deliberate. Probably it would never have occurred to us (as a serious hypothesis) that the world could be based on anything else, had we not been under the impression that

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there was a rival stuff with a more comfortable kind of “concrete” reality⎯something too inert and stupid to be capable of forging an illusion. The rival turns out to be a schedule of pointer readings; and though a world of symbolic character can well be constructed from it, this is a mere shelving of the inquiry into the nature of the world of experience....

. The only subject presented to me for study is the content of my consciousness. You are able to communicate to me part of the content of your consciousness which thereby becomes accessible in my own. For reasons which are generally admitted, though I should not like to have to prove that they are conclusive, I grant your consciousness equal status with my own; and I use this secondhand part of my consciousness to “put myself in your place.” Accordingly my subject of study becomes differentiated into the contents of many consciousnesses, each content constituting a view-point. There then arises the problem of combining the view-points, and it is through this that the external world of physics arises. Much that is in any one consciousness is individual, much is apparently alterable by volition; but there is a stable element which is common to other consciousnesses. That common element we desire to study, to describe as fully and accurately as possible, and to discover the laws by which it combines now with one view-point, now with another. This common element cannot be placed in one man’s consciousness rather than in another’s; it must be in neutral ground⎯an external world. It is true that I have a strong impression of an external world apart from any communication with other conscious beings. But apart from such communication I should have no reason to trust the impression. Most of our common impressions of substance, world-wide instants, and so on, have turned out to be illusory, and the externality of the world might be equally untrustworthy. The impression of externality is equally strong in the world that comes to me in dreams; the dream-world is less rational, but that might be used as an argument in favor of its externality as showing its dissociation from the internal faculty of reason. So long as we have to deal with one consciousness alone, the hypothesis that there is an external world responsible for part of what appears in it is an idle one. All that can be asserted of this external world is a mere duplication of the knowledge that can be much more confidently asserted of the world appearing in the consciousness. The hypothesis only becomes useful when it is the means of bringing together the worlds of many consciousnesses occupying different view-points. The external world of physics is thus a symposium of the worlds presented to different view-points. There is general agreement as to the principles on which the symposium should be formed. Statements made about this external world, if they are unambiguous, must be either true or false. This has often been denied by philosophers. It is quite commonly said that scientific theories about the world are neither true nor false but merely convenient or inconvenient. A favorite phrase is that the gauge of value of a scientific theory is that it economizes thought. Certainly a simple statement is preferable to a circumlocutory one; and as regards any current scientific theory, it is much easier to show that it is convenient or that it economizes thought than that it is true. But whatever lower standards we may apply in practice we need not give up our ideals; and so long as there is a distinction between true and false theories our aim must be to eliminate the false. For my part I hold that the continual advance of science is not a mere utilitarian progress; it is progress towards ever purer truth. Only let it be understood that the truth we seek in science is the truth about an external world propounded as the theme of study,

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and is not bound up with any opinion as to the status of that world⎯whether or not it wears the halo of reality, whether or not it is deserving of “loud cheers.” Assuming that the symposium has been correctly carried out, the external world and all that appears in it are called real without further ado. When we (scientists) assert of anything in the external world that it is real and that it exist, we are expressing our belief that the rules of the symposium have been correctly applied⎯that it is not a false concept introduced by an error in the process of synthesis, or a hallucination belong to only one individual consciousness, or an incomplete representation which embraces certain view-points but conflicts with others. We refuse to contemplate the awful contingency that the external world, after all our care in arriving at it, might be disqualified by failing to exist; because we have no idea what the supposed qualification would consist in, or in what way the prestige of the world would be enhanced if it passed the implied test.

The external world is the world that confronts that experience which we have in common, and for us no other world could fill the same rôle, no matter how high honors it might take in the qualifying examination. This domestic definition of existence for scientific purposes follows the principle now adopted for all other definitions in science, namely, that a thing must be defined according to the way in which it is in practice recognized and not according to some ulterior significance that we imagine it to possess. Just as matter must shed its conception of substantiality, so existence must shed its halo, before we can admit it into physical science. But clearly if we are to assert or to question the existence of anything not comprised in the external world of physics, we must look beyond the physical definition. The mere questioning of the reality of the physical world implies some higher censorship than the scientific method itself can supply. The external world of physics has been formulated as an answer to a particular problem encountered in human experience. Officially the scientist regards it as a problem which he just happened across, as he might take up a cross-word problem encountered in a newspaper. His sole business is to see that the problem is correctly solved. But questions may be raised about a problem which play no part and need not be considered in connection with the solving of the problem. The extraneous question naturally raised about the problem of the external world is whether there is some higher justification for embarking on this world-solving competition rather than on other problems which our experience might suggest to us. Just what kind of justification the scientist would claim for his quest is not very clear, because it is not within the province of science to formulate such a claim. But certainly he makes claims which do not rest on the aesthetic perfection of the solution or on material benefits derived from scientific research. He would not allow his subject to be shoved aside in a symposium on truth. We can scarcely say anything more definite than that science claims a “halo” for its world. If we are to find for the atoms and electrons of the external world not merely a conventional reality but “reality (loud cheers)” we must look not to the end but to the beginning of the quest. It is at the beginning that we must find that sanction which raises these entities above the mere products of an arbitrary mental exercise. This involves some kind of assessment of the impulse which sets us forth on the voyage of discovery. How can we make such an assessment? Not by any reasoning that I know of. Reasoning would only tell us that the impulse must be judged by the success of the

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adventure⎯whether it leads in the end to things which really exist and wear the halo in their own right; it takes us to and fro like a shuttle along the chain of inference in vain search of the elusive halo. But, legitimately or not, the mind is confident that it can distinguish certain quests as sanctioned by indisputable authority. We may put it in different ways; the impulse to this quest is part of our very nature; it is the expression of a purpose which has possession of us. Is this precisely what we meant when we sought to affirm the reality of the external world? It goes some way towards giving it a meaning but is scarcely the full equivalent. I doubt if we really satisfy the conceptions behind that demand unless we make the bolder hypothesis that the quest and all that is reached by it are of worth in the eyes of an Absolute Valuer. Whatever justification at the source we accept to vindicate the reality of the external world, it can scarcely fail to admit on the same footing much that is outside physical science. Although no long chains of regularized inference depend form them we recognize that other fibers of our being extend in directions away from senseimpressions. I am not greatly concerned to borrow words like “existence” and “reality” to crown these other departments of the soul’s interest. I would rather put it that any raising of the question of reality in its transcendental sense (whether the question emanates from the world of physics or not) leads us to a perspective from which we see man not as a bundle of sensory expressions, but conscious of purpose and responsibilities to which the external world is subordinate.

....

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8246940/

Bridgeman A year later, Bridgman (1928) repeated this warning in a review of Norman Campbell's An Account of the Principles of Measurement and Calculation—a book that seems to defend an equally rigorous view about meaning. In his review, Bridgman (1928, p. 999) mentioned that he is “not in sympathy with the […] view […] that there are in nature things which may be defined with the complete logical precision which we have come to associate with the entities of the mathematician.”

.....

Bridgman's criterion allowed Johnson could appeal to methodological prescriptions developed by a world‐renowned physicist and formulate the even stronger objection that the notion of introspectional sensation is meaningless if it cannot be operationally defined.

AR: in communicating tosomeone else,perhaps, but I can know it directly

a method of criticism first formulated with respect to scientific concepts by Ernst Mach and perhaps better stated by Henri Poincaré. To the works of these men and to Bridgman's excellent application of the method to more modern concepts

One of Skinner's reasons for writing the book on epistemology, these notes show, was his dissatisfaction with the widespread influence of phenomenalism—the radical empiricist view that physical objects are nothing but constructions out of primary sense experiences (“phenomena”). In the early 1930s, phenomenalism was a popular view about the nature of our knowledge about the physical world, defended by epistemologists, psychologists, and influential physicists like Arthur Eddington and James Jeans. When Skinner started working on his Sketch, both Eddington (The Nature of the Physical World) and Jeans (The Mysterious Universe) had just published books that relied on strongly phenomenalist conceptions of science. Skinner, on the other hand, strongly objected to the growing popularity of phenomenalism. In one his notes in Sketch for an Epistemology, he described the situation as follows:

Recent trends are toward a solution of the dilemmas of physics in terms of a theory of knowledge. It would be a pity if physicists in turning to epistemology should take up an out‐moded scheme of mind, which presents as many difficulties in its own systematization as the physicist is trying to rid himself of in physics. Jeans and Eddington are already out of the frying pan into the fire. This movement cannot be traced to one source. On the one hand lies positivism, on the other Ernst Mach (HUGFP 60.50, box 3, folder 5, my transcription)

Skinner's reference to Mach seems surprising considering the fact that his work on the notion of “reflex” was modeled on the latter's The Science of Mechanics. Still, Skinner's early notes show that he strongly disagreed with Mach's The Analysis of Sensations, a book he read as a staunch defense of phenomenalism. According to Skinner, Mach had it exactly backward: we do not need a phenomenalistic analysis of science, we need a scientific analysis of “phenomena”:

Mach reduces the concepts of science to a subjective basis […] we can return to an objective expression by asking him for a definition of sensation. This can only be supplied […] in terms of Mach's behavior (as a scientist). Thus while Mach makes science personal (and therefore private), the definition of sensation makes it again public, i.e. a matter of human behavior (HUGFP 60.50, box 3, folder 5, my transcription)

Whereas epistemologists and mentalistic psychologists aimed to secure our scientific knowledge by reconstructing our fallible concepts and theories out of “indubitable” sense experiences, Skinner aimed to revert the picture: we should not aim to ground science in sensation, we should ground sensation in behavioral science.

It is no coincidence that Skinner demands a public definition of sensation in arguing against phenomenalism. Sketch for an Epistemology is written from what Skinner considered to be an operationist perspective. Skinner notes that we ought to try “the operational method on ‘knowledge,'” that knowledge should be “operationally defined,” and that historical advances in the sciences might be explained by the fact that scientists (unconsciously) relied on “a positivistic (Machian, Poincarean, Bridgmanian) philosophy of science” (HUGFP 60.50, Box 3, Folder 5). Skinner, in other words, argued against the phenomenalists' attempts to reduce science to sense experience by applying Bridgman's call for conceptual hygiene to notions like “knowledge,” “mind,” and “sensation”; the phenomenalists' proposals are simply meaningless if they do not provide an operational definition of “sense experience.” Skinner, of course, believed that the only viable definition of sense experience would be a behavioristic one.

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https://en.wikipedia.org/wiki/Phenomenalism

Phenomenalism is the view that physical objects cannot justifiably be said to exist in themselves, but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in time and in space. In particular, some forms of phenomenalism reduce talk about physical objects in the external world to talk about bundles of sense-data.History[edit]

Phenomenalism is a radical form of empiricism. Its roots as an ontological view of the nature of existence can be traced back to George Berkeley and his subjective idealism, upon which David Hume further elaborated.^[1] John Stuart Mill had a theory of perception which is commonly referred to as classical phenomenalism. This differs from Berkeley's idealism in its account of how objects continue to exist when no one is perceiving them (this view is also known as "local realism"). Berkeley claimed that an omniscient God perceived all objects and that this was what kept them in existence, whereas Mill claimed that permanent possibilities of experience were sufficient for an object's existence. These permanent possibilities could be analysed into counterfactual conditionals, such as "if I were to have y-type sensations, then I would also have x-type sensations".

As an epistemological theory about the possibility of knowledge of objects in the external world, however, it is probable that the most easily understandable formulation of phenomenalism is to be found in the transcendental aesthetics of Immanuel Kant. According to Kant, space and time, which are the a priori forms and preconditions of all sensory experience, "refer to objects only to the extent that these are considered as phenomena, but do not represent the things in themselves". While Kant insisted that knowledge is limited to phenomena, he never denied or excluded the existence of objects which were not knowable by way of experience, the things-in-themselves or noumena, though he never proved them.

Kant's "epistemological phenomenalism", as it has been called, is therefore quite distinct from Berkeley's earlier ontological version. In Berkeley's view, the so-called "things-in-themselves" do not exist except as subjectively perceived bundles of sensations which are guaranteed consistency and permanence because they are constantly perceived by the mind of God. Hence, while Berkeley holds that objects are merely bundles of sensations (see bundle theory), Kant holds (unlike other bundle theorists) that objects do not cease to exist when they are no longer perceived by some merely human subject or mind.

In the late 19th century, an even more extreme form of phenomenalism was formulated by Ernst Mach, later developed and refined by Russell, Ayer and the logical positivists. Mach rejected the existence of God and also denied that phenomena were data experienced by the mind or consciousness of subjects. Instead, Mach held sensory phenomena to be "pure data" whose existence was to be considered anterior to any arbitrary distinction between mental and physical categories of phenomena. In this way, it was Mach who formulated the key thesis of phenomenalism, which separates it from bundle theories of objects: objects are logical constructions out of sense-data or ideas; whereas according to bundle theories, objects are made up of sets, or bundles, of actual ideas or perceptions.

That is, according to bundle theory, to say that the pear before me exists is simply to say that certain properties (greenness, hardness, etc.) are being perceived at this moment. When these characteristics are no longer perceived or experienced by anyone, then the object (pear, in this case) no longer exists. Phenomenalism as formulated by Mach, in contrast, is the view that objects are logical constructions out of perceptual properties. On this view, to say there is a table in the other room when there is no one in that room to perceive it, is to say that if there were someone in that room, then that person would perceive the table. It is not the actual perception that counts, but the conditional possibility of perceiving.

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https://plato.stanford.edu/entries/genrel-early/

A world geometry is not the physical theory of such a world but a framework or “graphical representation” within whose terms existing physical theory might be displayed, essentially through a purely formal identification of known tensors of the existing physical laws of gravitation and electromagnetism with those derived within the world geometry. Such a geometrical representation of physics cannot really be said to be right or wrong, for it only implements, if it can, current ideas governing the conception of objects and properties of an impersonal objective external world. But when existing physics, in particular, Einstein’s theory of gravitation, is set in the context of Eddington’s world geometry, it yields a surprising consequence: The Einstein law of gravitation appears as a definition! In the form Rμν = 0 it defines what in the “world geometry” appears to the mind as “vacuum” while in the form of the Einstein field equation noted above, it defines what is to be encountered by the mind as “matter”. This result is what is meant by his stated claim of throwing “new light on the origin of the fundamental laws of physics” (see Ryckman 2005: chapters 7 & 8). Eddington’s notoriously difficult and opaque later works (1936, 1946), took their inspiration from this argumentation in attempting to carry out a similar, algebraic not geometric, program of deriving fundamental physical laws, and the constants occurring in them, from a priori epistemological principles.

5.6 Meyerson on “Pangeometrism”

Within physics the idealist currents lying behind the world geometries of Weyl and Eddington were largely ignored, whereas within philosophy, with the notable exception of Émile Meyerson’s La Déduction Relativiste (1925). Meyerson, who had no doubt concerning the basic realist impetus of science, carefully distinguished Einstein’s “rational deduction of the physical world” from the speculative geometrical unifications of gravitation and electromagnetism of Weyl and Eddington. These theories, as affirmations of a complete panmathematicism, or rather of a pangeometrism (1925: §§ 157–58), were compared to the rationalist deductions of Hegel’s Logic. That general relativity succeeded in partly realizing Descartes’ program of reducing the physical to the spatial through geometric deduction, is due to the fact that Einstein “followed in the footsteps” of Descartes, not Hegel (1925: §133). But pan-geometrism is also capable of overreaching itself and this is the transgression committed by both Weyl and Eddington. Weyl in particular is singled out for criticism for seemingly to have reverted to Hegel’s monistic idealism, and so to be subject to its fatal flaw. In regarding nature as completely intelligible, Weyl had abolished the thing-in-itself and so promoted the identity of self and non-self, the great error of the Naturphilosophien.

Though he had “all due respect to the writings of such distinguished scientists” as Weyl and Eddington, Meyerson took their overt affirmations of idealism to be misguided attempts “to associate themselves with a philosophical point of view that is in fact quite foreign to the relativistic doctrine” (1925: §150). That “point of view” is in fact two distinct species of transcendental idealism. It is above all “foreign” to relativity theory because Meyerson cannot see how it is possible to “reintegrate the four-dimensional world of relativity theory into the self”. After all, Kant’s own argument for Transcendental Idealism proceeded “in a single step”, in establishing the subjectivity of the space and time of “our naïve intuition”. But this still leaves “the four dimensional universe of relativity independent of the self”. Any attempt to “reintegrate” four-dimensional spacetime into the self would have to proceed at a “second stage” where, additionally, there would be no “solid foundation” such as spatial and temporal intuition furnished Kant at the first stage. Perhaps, Meyerson allowed, there is indeed “another intuition, purely mathematical in nature”, lying behind spatial and temporal intuition, and capable of “imagining the four-dimensional universe, to which, in turn, it makes reality conform”. This would make intuition a “two-stage mechanism”. While all of this is not “inconceivable”, it does appear, nonetheless, “rather complex and difficult if one reflects upon it”. In any case, this is likely to be unnecessary, for considering the matter “with an open mind”,

one would seem to be led to the position of those who believe that relativity theory tends to destroy the concept of Kantian intuition. (1925: §§ 151–2)

Meyerson had come right up to the threshold of grasping the Weyl-Eddington geometric unification schemes in something like the sense in which they were intended. The stumbling block for him, and for others, is the conviction that transcendental idealism can be supported only from an argument about the nature of intuition, and intuitive representation. To be sure, the geometric framework for Weyl’s construction of the objective four-dimensional world of relativity is based upon the Evidenz available in “essential insight”, which is limited to the simple linear relations and mappings in what is basically the tangent vector space

T P TP at a point P in a manifold. Thus in Weyl’s differential geometry there is a fundamental divide between integrable and non-integrable relations of comparison. The latter are primitive and epistemologically privileged, but nonetheless not justified until it is shown how the infinitesimal homogeneous spaces, corresponding to the “essence of space as a form of intuition”, are compatible with the large-scale inhomogeneous spaces (spacetimes) of general relativity. And this required not a philosophical argument about the nature of intuition, but one formulated in group-theoretic conceptual form (Weyl 1923a,b). Eddington, on the other hand, without the cultural context of Husserlian phenomenology or indeed of philosophy generally, jettisoned the intuitional basis of transcendental idealism altogether, as if unaware of its prominence. Thus he sought a superior and completely general conceptual basis for the objective four-dimensional world of relativity theory by constituting that world within a geometry (its “world structure” (1923)) based upon a non-metrical affine (i.e., linear and symmetric) connection. He was then free to find his own way to the empirically confirmed integrable metric relations of Einstein’s theory without being hampered by the conflict of a “pure infinitesimal” metric with the observed facts about atomic spectra.

• Sir Arthur Eddington: "Not once in the dim past, but continuously by conscious mind is the miracle of the Creation wrought. All through the physical world runs that unknown content, which must surely be the stuff of our consciousness. . . . Where science has progressed the farthest, the mind has but regained from nature that which the mind has put into nature. We have found a strange foot-print on the shores of the unknown. We have devised profound theories, one after another, to account for its origin. At last, we have succeeded in reconstructing the creature that made the foot-print. And Lo! it is our own."
  McCabe[5] reports regarding Eddington's idealistic beliefs: "Pressed to say whether this meant that he rejected the common scientific teaching that a material universe really existed before life and mind appeared on this planet, he made fun of the word "really," and even said: "I do not think we understand what we mean by existence."

Eddington: “The mind-stuff of the world is, of course, something more general than our individual conscious minds.... It is difficult for the matter-of-fact physicist to accept the view that the substratum of everything is of mental character. But no one can deny that mind is the first and most direct thing in our experience, and all else is remote inference.” Arthur Stanley Eddington, The Nature Of The Physical World]

in speaking of "mindstuff": choose one below:

• he is not saying it is anything contradictory to the position of the naturalist/materialist

• he seems to be implying that it is qualitatively other than everything else - ie other than what is covered by physics, different than that which the materialist/naturalist says is all that is existent.

Einstein:

Essay: "What I believe" : [AR: Need to see the original,,maybe it was in German and the meaning of the term conscious life as used here; but] it seems he is referring to what we know as consciousness and considering it a mystery, I think it is clear that he was not a naturalist and considered that he KNEW of the existence of mind which is NOT part of phsyics in the way he 'mind' of the naturlaist is.

• “It is enough for me to contemplate the mystery of conscious life [perpetuating itself through all eternity, to reflect upon the marvelous structure of the universe which we dimly perceive, and to try humbly to comprehend an infinitesimal part of the intelligence manifested in nature.”]

• "The most beautiful thing we can experience is the mysterious. It is the source of all true art and science. He to whom the emotion is a stranger, who can no longer pause to wonder and stand wrapped in awe, is as good as dead; his eyes are closed. The insight into the mystery of life, coupled though it be with fear, has also given rise to religion. To know what is impenetrable to us really exists, manifesting itself as the highest wisdom and the most radiant beauty, which our dull faculties can comprehend only in their most primitive forms-this knowledge, this feeling is at the center of true religiousness."

• Scientific research can reduce superstition by encouraging people to think and view things in terms of cause and effect. Certain it is that a conviction, akin to religious feeling, of the rationality and intelligibility of the world lies behind all scientific work of a higher order. [...] This firm belief, a belief bound up with a deep feeling, in a superior mind that reveals itself in the world of experience, represents my conception of God. In common parlance this may be described as "pantheistic" (Spinoza).^[

• My religiosity consists in a humble admiration of the infinitely superior spirit that reveals itself in the little that we, with our weak and transitory understanding, can comprehend of reality

• Einstein believed naïve realism was "relatively simple" to disprove. He agreed with Bertrand Russell that humans observe the effects objects have on them (greenness, coldness, hardness, etc.) and not the actual objects themselves.^[75]

• Einstein declared that he was no positivist,^[90] and maintained that we use with a certain right concepts to which there is no access from the materials of sensory experience.^[91]

• In his 1934 book The World as I See It, Einstein expanded on his religiosity, "A knowledge of the existence of something we cannot penetrate, of the manifestations of the profoundest reason and the most radiant beauty, which are only accessible to our reason in their most elementary forms — it is this knowledge and this emotion that constitute the truly religious attitude; in this sense, and in this alone, I am a deeply religious man."^[38]

• In 1936 Einstein received a letter from a schoolirl asking if scientists pray. Einstein replied"Scientific research is based on the idea that everything that takes place is determined by laws of nature, and therefore this holds for the actions of people. For this reason, a research scientist will hardly be inclined to believe that events could be influenced by a prayer, i.e. by a wish addressed to a supernatural being. However, it must be admitted that our actual knowledge of these laws is only imperfect and fragmentary, so that, actually, the belief in the existence of basic all-embracing laws in nature also rests on a sort of faith. All the same this faith has been largely justified so far by the success of scientific research. But, on the other hand, everyone who is seriously involved in the pursuit of science becomes convinced that a spirit is manifest in the laws of the universe—a spirit vastly superior to that of man, and one in the face of which we with our modest powers must feel humble. In this way the pursuit of science leads to a religious feeling of a special sort, which is indeed quite different from the religiosity of someone more naive.”^[39]

...

Jeans (English physicist, astronomer and mathematician): "The stream of knowledge is heading towards a non-mechanical reality; the Universe begins to look more like a great thought than like a great machine. Mind no longer appears to be an accidental intruder into the realm of matter... we ought rather hail it as the creator and governor of the realm of matter." [James Jeans in The Mysterious Universe, ^[14]]

In an interview published in The Observer (London), when asked the question "Do you believe that life on this planet is the result of some sort of accident, or do you believe that it is a part of some great scheme?", he replied:

I incline to the idealistic theory that consciousness is fundamental, and that the material universe is derivative from consciousness, not consciousness from the material universe... In general the universe seems to me to be nearer to a great thought than to a great machine. It may well be, it seems to me, that each individual consciousness ought to be compared to a brain-cell in a universal mind.

What remains is in any case very different from the full-blooded matter and the forbidding materialism of the Victorian scientist. His objective and material universe is proved to consist of little more than constructs of our own minds. To this extent, then, modern physics has moved in the direction of philosophic idealism. Mind and matter, if not proved to be of similar nature, are at least found to be ingredients of one single system. There is no longer room for the kind of dualism which has haunted philosophy since the days of Descartes.

— James Jeans, addressing the British Association in 1934, recorded in Physics and Philosophy, ^[15]

Finite picture whose dimensions are a certain amount of space and a certain amount of time; the protons and electrons are the streaks of paint which define the picture against its space-time background. Traveling as far back in time as we can, brings us not to the creation of the picture, but to its edge; the creation of the picture lies as much outside the picture as the artist is outside his canvas. On this view, discussing the creation of the universe in terms of time and space is like trying to discover the artist and the action of painting, by going to the edge of the canvas. This brings us very near to those philosophical systems which regard the universe as a thought in the mind of its Creator, thereby reducing all discussion of material creation to futility.

— James Jeans in The Universe Around Us, ^[16]