Our Knowledge of the Internal World
23 March 2014
In the spring of 1914, just before the outbreak of World War 1 (and exactly one hundred years ago as I write this), Bertrand Russell gave a series of Lowell Lectures later published as Our Knowledge of the External World. This is a classic exposition of Russell’s thought which had a significant influence on Anglo-American analytical philosophy.
In the audience for one of the later iterations of these lectures was Will Durant, the noted American historian, whose The Story of Philosophy was so successful in the inter-war years that it freed him up to write his multi-volume The Story of Civilization. In The Story of Philosophy Durant wrote of Russell’s 1914 lectures:
“When Bertrand Russell spoke at Columbia University in 1914, he looked like his subject, which was epistemology — thin, pale, and moribund; one expected to see him die at every period. The Great War had just broken out, and this tender-minded, peace-loving philosopher had suffered from the shock of seeing the most civilized of continents disintegrate into barbarism. One imagined that he spoke of so remote a subject as ‘Our Knowledge of the External World’ because he knew it was remote, and wished to be as far as possible from actualities that had become so grim. And then, seeing him again, ten years later, one was happy to find him, though fifty-two, hale and jolly, and buoyant with a still rebellious energy. This despite an intervening decade that had destroyed almost all his hopes, loosened all his friendships, and broken almost all the threads of his once sheltered and aristocratic life.”
Will Durant, The Story of Philosophy, New York: Time Incorporated, 1962, pp. 442-443
Others were more moved by Russell’s thin, pale, and moribund epistemology. Rudolf Carnap read the lectures in book form, and describes the experience in terms reminiscent of a religious conversion:
…in my philosophical thinking in general I learned most from Bertrand Russell. In the winter of 1921 I read his book, Our Knowledge of the External World, as a Field For Scientific Method in Philosophy. Some passages made an especially vivid impression on me because they formulated clearly and explicitly a view of the aim and method of philosophy which I had implicitly held for some time. In the Preface he speaks about “the logical-analytic method of philosophy” and refers to Frege’s work as the first complete example of this method. And on the very last pages of the book he gives a summarizing characterization of this philosophical method in the following words:
The study of logic becomes the central study in philosophy: it gives the method of research in philosophy, just as mathematics gives the method in physics…
All this supposed knowledge in the traditional systems must be swept away, and a new beginning must be made… To the large and still growing body of men engaged in the pursuit of science,… the new method, successful already in such time-honored problems as number, infinity, continuity, space and time, should make an appeal which the older methods have wholly failed to make… The one and only condition, I believe, which is necessary in order to secure for philosophy in the near future an achievement surpassing all that has hitherto been accomplished by philosophers, is the creation of a school of men with scientific training and philosophical interests, unhampered by the traditions of the past, and not misled by the literary methods of those who copy the ancients in all except their merits.
I felt as if this appeal had been directed to me personally. To work in this spirit would be my task from now on And indeed henceforth the application of the new logical instrument for the purposes of analyzing scientific concepts and of clarifying philosophical problems has been the essential aim of my philosophical activity.
Rudolf Carnap, “Intellectual Autobiography,” in The Philosophy of Rudolf Carnap, edited by Paul Arthur Schilpp, p. 13
Russell’s works set the tone and, to a slightly lesser extent, set the agenda for analytical philosophy, in writing such words that inspired and influenced the next generation of philosophers. While Carnap felt himself to be called to a new kind of philosophical work by Russell’s stirring pages, Russell was nevertheless following in a long and distinguished line, which is nothing other than then mainstream of Western philosophy from Aristotle through Descartes and Kant to Russell himself. Descartes is usually remembered for the “epistemological turn” that defines modern Western philosophy, but Descartes was very much schooled in Scholasticism, and Scholasticism was deeply Aristotelian, so that the unbroken line of European philosophy from Aristotle to Russell and beyond may be compared to the “Golden Chain” of philosophers in the Platonic succession of classical antiquity.
The Aristotelian succession of scientifically-minded philosophers tends to be logical rather than intuitive (Aristotle was the first to formulate a formal logic), analytical in its method rather than synthetic or eclectic, and empirical rather than idealistic. But all philosophers, Platonic or Aristotelian, are interested in ideas, and it is the way in which ideas are expressed and incorporated that differs between the two camps. The Aristotelians can no more do without ideas than the Platonists, though ideas tend to enter into Aristotelian thought by way of schematic conceptions that leave their imprint upon the empirical data, and subtly guide the interpretation of all experience.
Aristotle himself is perhaps the best exemplification of this schematization of empirical knowledge according to philosophical categories. The canonical quinquipartitie division of the senses goes back at least to Aristotle’s On the Soul (commonly known as De anima). That our senses consist of seeing, hearing, smelling, tasting, and touching is an idea due to Aristotle’s De anima, and while this division is based on human faculties of perception and has intuitive plausibility, there are ways in which the division is arbitrary. This is one of my favorite works by Aristotle, so I hope that the reader will understand when I say that Aristotle’s division of experience into five senses is arbitrary, that I say so as a reader who is sympathetic to Aristotle’s account.
The Aristotelian division of the senses into five has bequeathed us an impoverished conception of the self. If we think of how the sense of touch is described and incorporated into accounts of the senses, it is as though we were only capable of experiencing bodies as objectified, touched (or touching) from the outside but not felt from within. And yet we experience ourselves from within more continuously than any other form of human experience — even when we close our eyes and stop our ears. Interoception is how we experience our own bodies from the inside. That to say, a part of the world is “wired” from within by our nervous system (which is itself part of the world in turn), and reveals itself to us viscerally. This is one of the consequences of the fact that we human beings constitute the universe experiencing itself (albeit not the whole the universe, but only a very small part thereof).
Recently philosophy has made significant strides in doing justice to what we feel and what we know through our bodies, which is both complex and subtle, and therefore particularly vulnerable to schematic over-simplifying accounts such as Aristotle’s. (I have noted in several posts that recent philosophy of mind has focused on the embodiment of mind, which may be considered another expression of the felt need to do justice to the body.) There is, for example, a wide recognition of what are called kinesthetic sensations, which are the kind of sensations that you feel when you engage in physical activities. When you run, for example, you don’t merely feel the onrush of air evaporating your sweat on the surface of your skin, you also feel your muscles straining, and if something goes wrong you will really feel that. And unless you have one of many disorders, your body has an almost perfect subconscious knowledge of where each limb is in relation to every other limb, which is why we are able to feed ourselves without thinking about it. Because we don’t think about it, but have reduced this knowledge to habit, we don’t think of it as either sensation or knowledge, but it is both.
Even Sam Harris, who doesn’t spend much time on general epistemological inquiries in his books, made a point of citing a litany of bodily sensations:
“Your nervous system sections the undifferentiated buzz of the universe into separate channels of sight, sound, smell, taste, and touch, as well as other senses of lesser renown — proprioception, kinesthesia, enteroreception, and even echolocation.”
Sam Harris, The End of Faith: Religion, Terror, and the Future of Reason, New York and London: W. W. Norton & Company, 2005, “Reason in Exile,” p. 41
In this quote, with its allusion to the “undifferentiated buzz” of experience, there is a hint of William James:
“The baby, assailed by eyes, ears, nose, skin, and entrails at once, feels it all as one great blooming, buzzing, confusion; and to the very end of life, our location of all things in one space is due to the fact that the original extents or bignesses of all the sensations which came to our notice at once, coalesced together into one and the same space.”
William James, The Principles of Psychology, 1890, CHAPTER XIII, “discrimination and Comparison”
James in this short passage has put his finger right on two crucial aspects of perception: that the world comes to us in an undifferentiated welter of sensations, and that we somehow seamlessly knit together this welter into one and the same world. Much as our familiar senses are fully integrated in our experience, so that we experience one world, and not a world of sight, a world of sound, so too our visceral sensations of proprioception, kinaesthesia, and interoception are so subtly integrated that it is only with difficulty that we can distinguish them.
The example of echolocation (which Harris includes in his litany while admitting in a footnote that is not very acute in human beings, but is still present in a limited sense) is especially interesting, because it is a function of hearing that is not exactly identical to hearing as we usually think of hearing (that is to say, hearing that lies outside the Aristotelian template). Moreover, the sensory apparatus inside our skulls that is responsible for hearing is also responsible for vestibular sensations (see glossary below), so that one and the same sense organ allows us more than one perspective on one and the same world.
The seamless integration of sense experience is one of the great unappreciated aspects of the senses in philosophy. Of course, Kant’s transcendental aesthetic was centrally concerned with this problem, there is Husserl on passive synthesis, and there is (or was) Gestalt psychology, and other theories as to how this happens, but none of these are quite right. None of these formulations really drive home the blooming, buzzing confusion of sensation and the unity of the world this sensation reveals. This is the paradox of the one and the many as its manifests itself in sensation.
The feeling of weight, of how one’s body relates to the Earth and to other bodies, is a sensation and that is so subtle and complex, involving both the senses recognized by Aristotle as well as the bodily sensations that Aristotle passed over in silence, that it is extraordinarily difficult to say where one sensation of weight leaves off and another picks up. Consequently, the feeling of weight is difficult to analyze, and most especially its relation to sight — which seems to provide the greater part of our conscious experience of the world — is negligible. When we realize how we typically express knowledge in visual metaphors — e.g., I see what you mean — the disconnect between sight and the feeling of weight takes an a special significance.
To introduce the feeling of weight immediately suggests also the feeling of weightlessness — zero gravity or microgravity conditions, as one experiences in Earth orbit or in deep space. Only a very small number of human beings have experienced weightlessness, and I am not among those few, but I will assume that interoception is fully implicated in the experience of weightlessness. But it is much more than this. Simply put, the experience of weight is the experience of gravity, and, by way of interoception, our body entire is an organ for the sensation of the very fabric of spacetime — our knowledge of the external world by way of our knowledge of the internal world.
When we stand on the surface of Earth and look up at the stars, we also feel the gravity of Earth throughout our body, pulling insistently on every part of us and forcing us to recognize continuously and without exception our physical relationship to Earth. In the most intimate and visceral ways we sense through our animal bodies the great forces that shape planets, stars, galaxies, and the universe entire. We know spacetime not as a mere abstraction, but as a constitutive part of our being. This intimate knowledge of spacetime has shaped our intuitive knowledge and understanding of our place in the cosmos, much as our ability to see the stars has similarly shaped our sense of ourselves as part of the universe. (This is what I called, in a recent post on my other blog, Visceral Cosmology.)
It is not only the visceral sensation of our own spatiality that we know through interoception, but also our own temporality. We not only sense time in the Aristotelian sense as the measure of motion (seeing change in the world), but our minds also give us a personal consciousness of the passage of time. This is as remarkable as our sensation of gravity (i.e., spacetime curvature). Our internal time consciousness, so tied up in our personal identity, reflects the larger temporal structure of the universe, pointing in the same direction as the other arrows of time, and giving us another immediate form or intuition into the very structure of the world. The gnawing tooth of time that ultimately shapes everything in the world also gnaws away inside us.
Our minds and the intuitions that it has about the world have been no less shaped by gravity and time than have our bodies. And in so far as gravity is the distortion of spacetime in the presence of mass, our visceral feelings of weight, as well as our consciousness of time, gives us an immediate intuitive perception of the curvature of spacetime. We possess a kind of interoception of the cosmos. We feel the world in our bones and sinews, as it were.
Here lies a crucial clue to understanding the Overview Effect (cf. The Epistemic Overview Effect, The Overview Effect as Perspective Taking, Hegel and the Overview Effect, and The Overview Effect in Formal Thought) Discussions of the overview effect tend to focus on seeing the Earth whole from space, and this is no doubt crucial to the experience, but the viscerality of the experience comes from the countless sensations of microgravity that are too subtle to describe and too numerous to clearly differentiate. It is the visceral experience of being off the surface of Earth combined with the evidence of one’s eyes that Earth lies before one, suspended in space as one is oneself suspended in space, that is the overview effect.
All human history up until the flight of Yuri Gagarin had taken place on the surface of Earth. In Wittgensteinian terms, nothing up to that point in time had contrasted with the form of terrestrial experience (cf. Nothing contrasts with the form of the world). With the visceral experience of being in space, suddenly there is a contrast where before there was none: the sensation of being on Earth, and the sensation of being off the surface of Earth, and subject to distinct (and distinctively different) gravitational conditions. The conditions of weight and weightlessness now define polar concepts, between which are a continuum of graded sensation; the polar concepts take part of their meaning from their contrast with the opposite polar concept, as do all points of experience along the continuum of the experience of weight.
Further technological developments that allow for unprecedented forms of human experience will also result in novel experiences of interoception. When we eventually build large artificial structures in space and spin them in order to imitate terrestrial gravity, there may be some individuals who cannot distinguish between this imitation of gravity and gravity on the surface of Earth, while other individuals may feel a difference. Some individuals may be made ill by the sensation, and in this way artificial structures will be strongly selective of who remains there — and therefore strongly selective of who does and does not create the human future in space.
When, in the further future, our technology allows us to travel at relativistic velocities, we will have yet further experiences of acceleration and of our personal consciousness of time in relation to time dilation, and the twin paradox that I have recently discussed (e.g., in Kierkegaard and Futurism) will prove to be not a limitation, but rather a revelation. We will learn things about ourselves and about the human condition that could not be learned in any other way than the actual experience of living in various extraterrestrial environments.
The overview effect is only the beginning of the human, all-too-human experience of space travel. The exploration of space will not only open new worlds to us beyond Earth, but will also open new inner worlds to us as the human condition expands to comprise unprecedented experiences that can have no parallel on Earth.
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A Note on Terminology: terminology is important, because our vocabulary for the internal experience of our bodies is relatively impoverished in comparison with the vocabulary at our command when it comes to our knowledge of the external world. Neither interoception or “enteroreception” appear in the Oxford English Dictionary. The Free Online Dictionary defines “interception” as “sensitivity to stimuli originating inside of the body.”
I found this distinction made between “enteroreception” and “exteroreception”: “Enteroreception or changes within the organsim that are detected by receptor cells within the organism. Exteroreception or changes that occur outside the orgnasim that are detected by receptor cells at the surface of the organism.”
I am here using “interoception” as a blanket term to cover all forms of visceral perception and sensation, though it might to worth considering coining a new term to cover all these uses, such as, for example, endoception.
There is an interesting glossary of terms related to interoception in The Senses of Touch: Haptics, Affects and Technologies by Mark Paterson (New York and Oxford: Berg, 2007):
Haptic Relating to the sense of touch in all its forms, including those below.
Proprioception Perception of the position, state and movement of the body and limbs in space. Includes cutaneous, kinaesthetic, and vestibular sensations.
Vestibular Pertaining to the perception of balance, head position, acceleration and deceleration. Information obtained from semi-circular canals in the inner ear.
Kinaesthesia The sensation of movement of body and limbs. Relating to sensations originating in muscles, tendons and joints.
Cutaneous Pertaining to the skin itself or the skin as a sense organ. Includes sensation of pressure, temperature and pain.
Tactile Pertaining to the cutaneous sense, but more specifically the sensation of pressure (from mechanoreceptors) rather than temperature (thermoceptors) or pain (nociceptors).
Force Feedback Relating to the mechanical production of information sensed by the human kinaesthetic system. Devices provide cutaneous and kinaesthetic feedback that usually correlates to the visual display.
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The Overview Effect
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