## The Overview Effect and Intuitive Tractability

### 26 March 2017

Sunday

Looking down on Earth from above may not only make us reevaluate out relationship to the planet, but may also help us to understand the planet better.

Science is a way to better understand the world, but science itself is not always easy to understand, and we often find that, after clarifying some problem through science, we must then clarify the science so that the science makes sense to us. Some call this science communication; I call it the pursuit of intuitive tractability.

While it is not part of science proper to seek intuitively tractable formulations, it is part of human nature to seek intuitively tractable formulations, as we are more satisfied with science formulated in intuitively tractable forms than with science that is not intuitively tractable. For example, there is, as yet, no intuitively tractable formulation of quantum theory, and this may be why Einstein famously wrote in a letter to Max Born that, “Quantum Mechanics is very impressive. But an inner voice tells me that it is not yet the real thing.”

When the concept of zero was introduced into mathematics, it was thought to be an advanced and difficult idea, but we now teach a number system starting with zero to children in primary school. In a similar way, the Hindu-Arabic system of numbers has displaced almost every other system of numbers because it is what I would paradoxically call an intuitive formalism, i.e., it is a formalization of the number concept that is both adequate to mathematics and closely follows our intuitive conception of number. Mathematics is easier with Hindu-Arabic numerals than other numbering systems because this numbering system is intuitively tractable. There are other formalisms for number that are equally valid and equally correct, but not as intuitively tractable.

The pursuit of intuitive tractability has also been evident in geometry, and especially the axiomatic exposition of geometry that begins with postulates accepted ab initio as self-evident, and which has been the model of rigorous mathematics ever since Euclid. Euclid’s fifth postulate, the famous parallel postulate, is difficult to understand and was a theoretical problem for geometry until its independence was proved, but whether or not the fifth postulate was demonstrably independent of the other postulates, Euclid’s opaque exposition did not help. Here is Euclid’s parallel axiom from the Elements:

“If a line segment intersects two straight lines forming two interior angles on the same side that sum to less than two right angles, then the two lines, if extended indefinitely, meet on that side on which the angles sum to less than two right angles.”

Almost two thousand years later, in 1846, John Playfair formulated what we now call “Playfair’s axiom,” which tells us everything that Euclid’s postulate sought to communicate, but in a far more intuitively tractable form: “In a plane, given a line and a point not on it, at most one line parallel to the given line can be drawn through the point.” Once this more intuitively tractable formulation of the parallel postulate was available, Euclid’s formulation was largely abandoned. There is, then, a process of cognitive selection, whereby the most intuitively tractable formulations are preserved and the less intuitively tractable formulations are abandoned.

Those concepts that are the most intuitively tractable are those concepts that are familiar to us all and which are seamlessly integrated into ordinary thought and language. I have called such concepts “folk concepts.” Folk concepts that have persisted from their origins in our earliest evolutionary psychology up into the present have been subjected to the cognitive equivalent of natural selection, so that we can reasonably speak of folk concepts as having been refined and elaborated by the experience of many generations.

In a series of posts — Folk Astrobiology, Folk Concepts of Scientific Civilization, and Folk Concepts and Scientific Progress — I have considered the nature of “folk” concepts as they have been frequently invoked, and it is natural to ask, in the light of such an inquiry, whether there is a “folk Weltanschauung” that is constituted by a cluster of folk concepts that naturally hang together, and which inform the pre-scientific (or non-scientific) way of thinking about the world.

Arguably, the idea of a folk Weltanschauung is already familiar by a number of different terms that philosophers have employed to identify the concept (or something like the concept) — naïve realism or common sense realism, for example. What Husserl called “natürliche Einstellung” and which Boyce Gibson translated as “natural standpoint” and Fred Kersten translated as “natural attitude” could be said to approximate a folk Weltanschauung. Here is how Husserl describes the natürliche Einstellung:

“I am conscious of a world endlessly spread out in space, endlessly becoming and having endlessly become in time. I am conscious of it: that signifies, above all, that intuitively I find it immediately, that I experience it. By my seeing, touching, hearing, and so forth, and in the different modes of sensuous perception, corporeal physical things with some spatial distribution or other are simply there for me, ‘on hand’ in the literal or the figurative sense, whether or not I am particularly heedful of them and busied with them in my considering, thinking, feeling, or willing.”

Edmund Husserl, Ideas Pertaining to a Pure Phenomenology and to a Phenomenological Philosophy: First Book: General Introduction to a Pure Phenomenology, translated by Fred Kersten, section 27

Husserl characterizes the natural attitude as a “thesis” — a thesis consisting of a series of posits of the unproblematic existence of ordinary objects — that can be suspended, set aside, as it were, by the phenomenological procedure of “bracketing.” These posits could be identified with folk concepts, making the thesis of the natural standpoint into a folk Weltanschauung, but I think this interpretation is a bit forced and not exactly what Husserl had in mind.

Perhaps closer to what I am getting at than the Husserlian natural attitude is what Wilfrid Sellars has called the manifest image of man-in-the-world, or simply the manifest image. Sellars’ thought is no easier to get a handle on than Husserl’s thought, so that one never quite knows if one has gotten it right, and one can easily imagine being lectured by a specialist in the inadequacies of one’s interpretation. Nevertheless, I think that Sellers’ manifest image is closer to what I am trying to get at than Husserl’s natürliche Einstellung. Closer, but still not the same.

Sellars develops the idea of the manifest image in contrast to the scientific image, and this distinction is especially given exposition in his essay Philosophy and the Scientific Image of Man. After initially characterizing the philosophical quest such that, “[i]t is… the ‘eye on the whole’ which distinguishes the philosophical enterprise,” and distinguishing several different senses in which philosophy could be said to be a synoptic effort at understanding the world as a whole, Sellars introduces terms for contrasting two distinct ways of seeing the world whole:

“…the philosopher is confronted not by one complex many dimensional picture, the unity of which, such as it is, he must come to appreciate; but by two pictures of essentially the same order of complexity, each of which purports to be a complete picture of man-in-the-world, and which, after separate scrutiny, he must fuse into one vision. Let me refer to these two perspectives, respectively, as the manifest and the scientific images of man-in-the-world.”

Wilfrid Sellars, Philosophy and the Scientific Image of Man, section 1

Sellars’ distinction between the manifest image and the scientific image has been quite influential. A special issue of the journal Humana Mente, Between Two Images: The Manifest and Scientific Conceptions of the Human Being, 50 Years On, focused on the two images. Bas C. van Fraassen in particular has written a lot about Sellars, devoting an entire book to one of the two images, The Scientific Image, and has also written several relevant papers, such as “On the Radical Incompleteness of the Manifest Image” (Proceedings of the Biennial Meeting of the Philosophy of Science Association,Vol. 1976, Volume Two: Symposia and Invited Papers 1976, pp. 335-343). All of this material is well worth reading.

Sellars is at pains to point out that his distinction between manifest image and scientific image is not intended to be a distinction between pre-scientific and scientific worldviews (“…what I mean by the manifest image is a refinement or sophistication of what might be called the ‘original’ image…”), though it is clear from this exposition that the manifest image, however refined and up-to-date, has its origins in a pre-scientific conception of the world. (“It is, first, the framework in terms of which man came to be aware of himself as man-in-the-world.”) The essence of this distinction between the manifest image and the scientific image is that the manifest image is correlational while the scientific image is postulational. What this means is that the manifest image “explains” the world (in so far as it could be said to explain the world at all) by correlations among observables, while the scientific image explains the world by positing unobservables that connect observables “under the surface” of things, as it were (involving, “…the postulation of imperceptible entities”). Sellars also maintains that the manifest image cannot postulate in this way, and therefore cannot be improved or refined by science, although it can improve on itself by its own correlational methods.

I do not yet understand Sellars well enough to say why he insists that the manifest image cannot incorporate insights from the scientific image, and this is a key point of divergence between Sellars’ manifest image and what I above called a folk Weltanschauung. If a folk Weltanschauung consists of a cluster of tightly-coupled folk concepts (and perhaps a wide penumbra of associated but loosely-coupled folk concepts), then the generation of refined scientific concepts can slowly, one-by-one, replace folk concepts, so that the folk Weltanschauung gradually evolves into a more scientific Weltanschauung, even if it is not entirely transformed under the influence of scientific concepts. Science, too, consists of a cluster of tightly-coupled concepts, and these two distinct clusters of concepts — the folk and the scientific — might well resist mixing for a time, but the human mind cannot keep such matters rigorously separate, and it is inevitable that each will bleed over into the other. Sometimes this “bleeding over” is intentional, as when science reaches for metaphors or non-scientific language as a way to make its findings understood to a wider audience. This is part of the pursuit of intuitively tractable formulations, but it can also go very wrong, as when scientists adopt theological language in an attempt at a popular exposition that will not be rejected out-of-hand by the Great Unwashed.

Despite my differences with Sellars, I am going to here adopt his terminology of the manifest image and the scientific image, and I will hope that I don’t make too much of a mess of it. I will have more to say on this use of Sellars’ concepts below (especially in relation to the postulational character of the scientific image). In the meantime, I want to use Sellars’ concepts in a exposition of intuitive tractability. Sellars’ uses the metaphor of “stereoscopic vision” as the proper way to understand how we must bring together the manifest image and the scientific image as a single way of understanding the world (“…the most appropriate analogy is stereoscopic vision, where two differing perspectives on a landscape are fused into one coherent experience”). I think, on the contrary, that intuitively tractable formulations of scientific concepts can make the manifest image and the scientific image coincide, so that they are one and the same, and not two distinct images fused together. A slightly weaker formulation of this is to assert that intuitively tractable formulations allow us to integrate the manifest image and the scientific image.

Now I want to illustrate this by reference to the overview effect, that is to say, the cognitive effect of seeing our planet whole — preferably from orbit, but, if not from orbit, in photographs and film that make the point as unmistakably as though one were there, in orbit, seeing it with one’s own eyes.

Before the overview effect, we saw our planet with the same eyes, but even after it is proved to us that the planet is (roughly) a sphere, hanging suspended in space, it is difficult to believe this. All manner of scientific proofs of the world as a spherical planet can be adduced, but the science lacks intuitive tractability and we have a difficult time bringing together our scientific concepts and our folk concepts of the world — or, if you will, we have difficulty reconciling the manifest image and the scientific image. The two are distinct. Until we achieve the overview effect, there is an apparent contradiction between what we experience of the world and our scientific knowledge of the world. Our senses tell us that the world is flat and solid and unmoving; scientific knowledge tells us that the world is round and moving and hanging in space.

Once we attain the overview effect, this changes, and the apparent contradiction is revealed as apparent. The overview effect shows how the manifest image and the scientific image coincide. The things we know about ordinary objects, which shapes the manifest image, now applies to Earth, which is seen as an object rather than as surrounding us as an environment with an horizon that we can never reach, and which therefore feels endless to us. Seen from orbit, this explains itself intuitively, and an explicit explanation now appears superfluous (as is ideally the case with an axiom — it is seen to be true as soon as it is understood). The overview effect makes the scientific knowledge of our planet as a planet intuitively tractable, transforming scientific truths into visceral truths. One might say that the overview effect is the lived experience of the scientific truth of our homeworld. In this particular case, we have replaced a folk concept with a scientific concept, and the scientific concept is correct even as intuition is satisfied.

The use of the overview effect to illustrate the manifest and scientific images, and their possible coincidence in a single experience, is especially interesting in light of Sellars’ insistence that the scientific image is distinctive because it is postulational, and more particularly that it postulates unobservables as a way to explain observables. When, in a scientific context, someone speaks of unobservables or “imperceptible entities” the assumption is that we are talking about entities that are too small to see with the naked eye. The germ theory of disease and the atomic theory of matter both exemplify this idea of unobservables being observable because they are smaller than the resolution of unaided human vision. We can only observe these unobservables with instruments, and then this experience is mediated by complex instruments and an even more complex conceptual framework so that no one ever speaks of the “lived experience” of particle physics or microbiology.

In contrast to this, the Earth is unobservable to the human eye not because it is too small, but because it is too large. When shown scientific demonstrations that the world is round, we must posit an unobservable planet, and then identify this unobservable entity with the actual ground under our feet. This is difficult to do, intuitively speaking. We see the world at all times, but we do not see it as a planet. We do not see enough of the world at any one moment to see it as a planet. Enter the overview effect. Seeing the Earth whole from space reveals the entity that is planet Earth, and if one has the good fortune to lift off from Earth and experience the process of departing from its surface to then see the same from space, this makes a previously unobservable postulate into a concretely experienced entity.

We are in the same position now vis-à-vis our place within the Milky Way galaxy, and our place within the larger universe, as we were once in relation to the spherical Earth. Our accumulated scientific knowledge tells us where we are at in the universe, and where we are at in the Milky Way. We can even see a portion of the Milky Way when we look up into the night sky, but we cannot stand back and see the whole from a distance, taking in the Milky Way and pointing of the position of our solar system within one of the spiral arms of our galaxy. We know it, but we haven’t yet experienced it viscerally. We have to posit the Milky Way galaxy as a whole, the Virgo supercluster, and the filaments of galaxies that stretch through the cosmos, because they are too large for us to observe at present. They are partially observed, in the way we might say that an atom is partially observed when we look at a piece of ordinary material composed of atoms.

Our postulational scientific image of the universe in which we live is redeemed for intuition by experiences that put us in a position to view these entities with our own eyes, and so to see them in an intuitively tractable manner. Perhaps one of the reasons that quantum theory remains intuitively intractable is that the unobservables that it posits are so small that we have no hope of ever seeing them, even with an electron microscope.

Ultimately, intuitively tractable formulations of formerly difficult if not opaque scientific ideas is a function of the conceptual framework that we employ, and this is ultimately a philosophical concern. Sellars suggests that the manifest and scientific conceptual framework might be harmonized in stereoscopic vision, but he doesn’t hold out any hope that the manifest image can be integrated with the scientific image. I think that the example of the overview effect demonstrates that there are at least some cases when manifest image and scientific image can be shown to coincide, and therefore these two ways of grasping the world are not entirely alien from each other. Cosmology may be the point of contact at which the two images coincide and through which the two images can communicate.

The pursuit of intuitive tractability is, I submit, a central concern of scientific civilization. If there ever is to be a fully scientific civilization, in which scientific ways of knowing and scientific approaches to problems and their solutions are the pervasively held view, this scientific civilization will come about because we have been successful in our pursuit of intuitive tractability, and we are able to make advanced scientific concepts as familiar as the idea of zero is now familiar to us. Since the question of a conceptual framework in which rigorous science and intuitively tractable concepts can be brought together is not a scientific question, but a philosophical question, the contemporary contempt for philosophy in the special sciences is invidious to the effective pursuit of intuitive tractability. The fate of scientific civilization lies with philosophy.

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Overview Effects

The Overview Effect and Intuitive Tractability

Homeworld Effects

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## Folk Astrobiology

### 6 August 2016

Saturday

If some alien species had encountered Earth during one of its snowball periods, the planet would have resembled a biosphere with a single biome.

Can there be folk concepts in (and of) recent and sophisticated scientific thought, such as astrobiology? Astrobiology is a recent discipline, and as such is a beneficiary of a long history of the development of scientific disciplines; in other words, astrobiology stands on the shoulders of giants. In From an Astrobiological Point of View I characterized astrobiology as the fourth and latest of four revolutions in the life sciences, preceded by Darwinism, genetics, and evolutionary developmental biology (i.e., evo-devo). Can there be folk concepts that influence such a recent scientific discipline?

In Folk Concepts and Scientific Progress and Folk Concepts of Scientific Civilization I considered the possibility of folk concepts unique to a scientific civilization, and the folk concepts of recent sciences like astrobiology constitute paradigmatic examples of folk concepts unique to scientific civilization. The concepts of folk astrobiology, far being being rare, have proliferated as science fiction has proliferated and made a place for itself in contemporary culture, especially in film and television.

One idea of folk astrobiology that is familiar from countless science fiction films is that of planets the biosphere of which is dominated by a single biome. Both Frank Herbert’s planet Arrakis from the novel Dune and the planets Tatooine and Jakku from Star Wars are primarily desert planets, whereas the Star Wars planet Dagobah is primarily swamp, the planet Kamino is a global ocean, and the planet Hoth is primarily arctic. Two worlds that appear in the Alien films, Zeta Reticuli exomoon LV-426 in Alien and Aliens and LV-223 in Prometheus, are both desolate, rocky, and barren, like the landscapes we have come to expect from the robotic exploration of the other worlds in our own solar system.

The knowledge we have assembled of the long-term history of the biosphere of Earth, that our planet has passed through “hothouse” and “icehouse” stages, suggest it is reasonable to suppose that we will find similar conditions elsewhere in the universe, though Earth today has a wide variety of biomes that make up its biosphere. We should expect to find worlds both with diverse biospheres and with biospheres primarily constituted by a single biome. Perhaps this idea of folk astrobiology will someday be formalized, when we know more about the evolution of biospheres of multiple worlds, and we have the data to plot a bell curve of small, rocky, wet planets in the habitable zone of their star. This bell curve almost certainly exists, we just don’t know as yet where Earth falls on the curve and what kinds of worlds populate the remainder of the curve.

Biosphere diversity is thus a familiar concept of folk astrobiology. But let me backtrack a bit and try to formulate more clearly an explication of folk astrobiology.

In an earlier post I quoted the following definition of folk biology:

Folk biology is the cognitive study of how people classify and reason about the organic world. Humans everywhere classify animals and plants into species-like groups as obvious to a modern scientist as to a Maya Indian. Such groups are primary loci for thinking about biological causes and relations (Mayr 1969). Historically, they provided a transtheoretical base for scientific biology in that different theories — including evolutionary theory — have sought to account for the apparent constancy of “common species” and the organic processes centering on them. In addition, these preferred groups have “from the most remote period… been classed in groups under groups” (Darwin 1859: 431). This taxonomic array provides a natural framework for inference, and an inductive compendium of information, about organic categories and properties. It is not as conventional or arbitrary in structure and content, nor as variable across cultures, as the assembly of entities into cosmologies, materials, or social groups. From the vantage of EVOLUTIONARY PSYCHOLOGY, such natural systems are arguably routine “habits of mind,” in part a natural selection for grasping relevant and recurrent “habits of the world.”

Robert Andrew Wilson and Frank C. Keil, The MIT Encyclopedia of the Cognitive Sciences

And here is a NASA definition of astrobiology that I have previously quoted:

“Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. This multidisciplinary field encompasses the search for habitable environments in our Solar System and habitable planets outside our Solar System, the search for evidence of prebiotic chemistry and life on Mars and other bodies in our Solar System, laboratory and field research into the origins and early evolution of life on Earth, and studies of the potential for life to adapt to challenges on Earth and in space.”

Drawing on both of these definitions — “Folk biology is the cognitive study of how people classify and reason about the organic world” and “Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe” — we can formulate a fairly succinct definition of folk astrobiology:

Folk astrobiology is the cognitive study of how people classify and reason about the origin, evolution, distribution, and future of life in the universe.

I hope that the reader immediately sees how common this exercise is, both in scientific and non-scientific thought. On the scientific side, folk astrobiology is pervasively present in the background assumptions of SETI, while on the non-scientific side, as we have seen above in examples drawn from scientific fiction films, folk astrobiology informs our depiction of other worlds and their inhabitants. These concepts of folk astrobiology are underdetermined by astrobiology, but well grounded in common sense and scientific knowledge as far as it extends today. We will only be able to fully redeem these ideas for science when we have empirical data from many worlds. We will begin to accumulate this data when, in the near future, we are able to get spectroscopic readings from exoplanet atmospheres, but that is only the thin edge of the wedge. Robust data sets for the evolution of multiple independent biospheres will have to await interstellar travel. (This is one reason that I suggested that a starship would be the ultimate scientific instrument; cf. The Interstellar Imperative.)

Folk astrobiology remains “folk” until its concepts are fully formalized as part of a rigorous scientific discipline. As few disciplines ever attain complete rigor (logic and mathematics have come closest to converging on that goal), there is always a trace of folk thought that survives in, and is even propagated along with, scientific thought. Folk concepts and scientific concepts, then, are not mutually exclusive, but rather they overlap and intersect in a Wittgensteinian fashion. However, the legacy of positivism has often encouraged us to see folk concepts and scientific concepts as mutually exclusive, and if one adopts the principle that scientific concepts must be reductionist, therefore no non-reductionist concepts are not scientific, then it follows that most folk concepts are eliminated when a body of knowledge is made scientifically rigorous (I will not further develop this idea at present, but I hope to return to it when I can formulate it with greater precision).

We have a sophisticated contemporary biological science, and thus scientific biological concepts are ready to hand to employ in astrobiology, so that astrobiology has an early advantage in converging upon scientific rigor. But if a science aspires to transcend its origins and to establish itself as a new science co-equal with its progenitors, it must be prepared to go beyond familiar concepts, and in this case this means going beyond the sophisticated concepts of contemporary biology in order to establish truly astrobiological scientific concepts, i.e., uniquely astrobiological concepts, and these distinctive and novel concepts must then, in their turn, converge on scientific rigor. In the case of astrobiology, this may mean formulating a “natural history” where “nature” is construed as to include the whole of the universe, and this idea transcends the familiar idea of natural history, forcing the astrobiologist to account for cosmology as well as biology.

As an example of an uniquely astrobiology concept I above suggested the idea of biosphere diversity. Biosphere diversity, in turn, is related to ideas of biosphere evolution, developmental stages on planets with later emergent complexities, and so on. The several posts I have written to date on planetary endemism (Part I, Part II, Part III, Part IV, Part V, and more to come) may be considered expositions of the folk astrobiological idea of planetary endemism. Similarly, the homeworld concept is both a folk concept of astrobiology and scientific civilization (cf. The Homeworld Effect and the Hunter-Gatherer Weltanschauung, Hunter-Gatherers in Outer Space, and The Martian Standpoint).

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The idea of a homeworld is a folk concept of astrobiology and scientific civilization.

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## Folk Concepts of Scientific Civilization

### 7 August 2015

Friday

Science in its early stages of development always makes use of folk concepts, and there is always some science in the early stages of its development.

Having provided an exposition of folk concepts in my Folk Concepts and Scientific Progress, I can move on to my motivation for thinking about folk concepts, which was to investigate the role of folk concepts in contemporary civilization, i.e., folk concepts in industrial-technological civilization, or scientific civilization, which latter seems paradoxical. How can folk concepts coexist with scientific civilization? If a civilization were truly scientific, would it not have overcome the use of folk concepts?

Scientific civilization in only about five hundred years old, and it may be divided into two portions, the period 1500-1800 (which I call Modernism without Industrialism, which is to say, the period between the scientific revolution and the industrial revolution) and the period after the industrial revolution (which marks the beginning of industrial-technological civilization, in which science is crucial to the STEM cycle, which drives this civilization).

I have considered the nature of scientific civilization in David Hume and Scientific Civilization and The Relevance of Philosophy of Science to Scientific Civilization, Addendum on the Stages of Civilization and The Perfectly Scientific Man: A Platonic Thought Experiment (and I am, additionally, working on several posts intended as further explorations of the idea of scientific civilization). To date I have only scratched the surface, and haven’t provided a sustained exposition of the idea of scientific civilization. This is a rich vein of inquiry for the study of civilization, and it will not be exhausted any time soon.

Paradoxical though it sounds, scientific civilization has its own folk concepts. This is because scientific civilization produces not only more refined and sophisticated sciences, but also entirely new sciences, and new sciences involve the introduction of new terms and concepts. Unprecedented developments — of which civilization itself is perhaps the most unprecedented development in human history — demand that we formulate a theoretical framework to intellectually assimilate them. Sometimes the technical and engineering capacities of industrial-technological civilization produce new entities, or new classes of entities (this is a source of planetary constraints on civilization, in the form of what I call the ontic constraint), and no established theoretical framework exists to assimilate these discoveries. Truly novel phenomena demand the formulation of a truly novel theoretical framework.

Eliminativism (as in, e.g., eliminative materialism) often takes the form of rejecting “folk” concepts as unscientific and insisting upon the replacement of folk concepts with scientific concepts. However, such a replacement of folk by scientific concepts can only work if there is a science of the phenomena to be explained. Where we possess no science, or only an inchoate science — I have many times observed that there is no science of civilization, and no science of consciousness — the elimination of folk concepts leaves us with little or nothing. Thus in the period of time during which a science is developing, and folk concepts and scientific concepts overlap, a scientific theory that incorporates folk concepts is less imperfect (because more adequate) than an inchoate scientific theory that attempts to entirely eliminate folk concepts ad initio.

Folk concepts can contribute to the adequacy of a conceptual framework because they typically draw upon what Michael Polanyi called tacit knowledge, i.e., what we know, but which we cannot account for knowing, or say how we know what we know. Recognizing faces in a crowd is a paradigm case of tacit knowledge. Human beings are very good at recognizing individual faces, but very poor at describing faces or explaining how they recognize a face. Tacit knowledge might also be characterized as knowledge below the level of formalization, or even knowledge below the level of conscious awareness.

While the rejection, elimination, and replacement of folk concepts is often justified, this rejection is often too sweeping in its elimination when it becomes a pretext to eliminate not only the admittedly imperfect and informal folk concept, but also the tacit knowledge upon which the folk concept is based. From a scientific standpoint, it is easy to dismiss tacit knowledge, as it resists precisely the formalization that science would like to impose upon all bodies of knowledge. There is often an attitude in the sciences that that which cannot be made fully explicit can be safely ignored, and there are good grounds for this, as the subtlety of tacit knowledge cannot be subjected to experimentation, repeatability, or public verification. Nevertheless, this is one of the sources of intuition that ultimately lies at the base of all the sciences. New sciences especially are reliant on tacit knowledge.

There is often an imperfect fit between our native intuitions and the ideas of a new science; new sciences often involve concepts that are counter-intuitive, and we must make the effort to formulate new intuitions, and arrive at new ways of thinking about familiar phenomenon. In some cases, our intuitions are utterly silent on questions posed by a new science or a new mode of inquiry, so that we must develop our intuitive competency as we proceed, which is a process that can take generations. In the meantime, folk concepts about new developments, about new phenomena, and even about new sciences grow up like weeds.

Even in the midst of unprecedented developments, life goes on, and since the ordinary business of life goes on, we discuss unprecedented developments in the ordinary language of ordinary life. Ordinary language may be defined in terms of its reliance upon folk concepts. However, ordinary language changes, albeit slowly. With the passage of sufficient time, ordinary language changes significantly. The ordinary language spoken in the context of agrarian-ecclesiastical civilization probably differed markedly from the ordinary language spoken in the context of industrial-technological civilization. Each kind of civilization has its distinctive kind of ordinary language. (If you like, you may consider this a weak formulation of the Sapir-Whorf hypothesis, though that is not how I would characterize it; I mention the hypothesis here only because I am certain that some readers will assimilate the argument made here to it.)

In Scientific Curiosity and Existential Need I argued that the distinctive character of scientific mystery (in contradistinction to the eschatological mysteries that seem to satisfy the longings of existential need) is that scientific mysteries are never final. Scientific knowledge in a scientific civilization is in a state of continual growth. Scientific mysteries are eventually solved, but they are at the same time replaced by ever new scientific mysteries, so that there always are and always will be scientific mysteries, but scientific mystery is not some impossible, ineffable truth about the universe that can never admit of rational knowledge. Scientific mysteries admit of definitive answers, and the phenomenon of scientific mystery mystery remains with us only because new scientific mysteries always appear beyond the mysteries that have been resolved.

This sense of there always being a further scientific mystery is well illustrated by a famous quote attributed to Isaac Newton:

“I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.”

Sir David Brewster, Memoirs of the Life, Writings, and Discoveries of Sir Isaac Newton, 1855, Volume II., Ch. 27.

The same structure of scientific knowledge that means that there are always new scientific mysteries also means that there will always be science on the frontier of knowledge, and science on the frontier of knowledge will always, at least in its inchoate beginnings, have recourse to folk concepts, however far in advance of contemporary knowledge these folk concepts may be.

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The Square Kilometer Array: SETI is still a very young science, and moreover a science that occurs at the intersection of the natural sciences and the social sciences. As such, it continues to make use of folk concepts of civilization and astrobiology.

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## Folk Concepts and Scientific Progress

### 2 August 2015

Sunday

For some philosophers, naturalism is simply an extension of physicalism, which was in turn an extension of materialism. Narrow conceptions of materialism had to be extended to account for physical phenomena not reducible to material objects (like theoretical terms in science), and we can similarly view naturalism as a broadening of physicalism in order to more adequately account for the world. (I have quoted definitions of materialism and physicalism in Materialism, Physicalism, and… What?.) But, coming from this perspective, naturalism is approached from a primarily reductivist or eliminativist point of view that places an emphasis upon economy rather than adequacy in the description of nature (on reductivism and eliminativism cf. my post Reduction, Emergence, Supervenience). Here the principle of parsimony is paramount.

One target of eliminativism and reductionism is a class of concepts sometimes called “folk” concepts. The identification of folk concepts in the exposition of philosophy of science can be traced to philosopher Daniel Dennett. Dennett introduced the term “folk psychology” in The Intentional Stance and thereafter employed the term throughout his books. Here is part of his original introduction of the idea:

“We learn to use folk psychology — as a vernacular social technology, a craft — but we don’t learn it self-consciously as a theory — we learn no meta-theory with the theory — and in this regard our knowledge of folk psychology is like our knowledge of the grammar of our native tongue. This fact does not make our knowledge of folk psychology entirely unlike human knowledge of explicit academic theories, however; one could probably be a good practising chemist and yet find it embarrassingly difficult to produce a satisfactory textbook definition of a metal or an ion.”

Daniel Dennett, The Intentional Stance, Chap. 3, “Three Kinds of Intentional Psychology”

Earlier (in the same chapter of the same book) Dennett had posited “folk physics”:

“In one sense people knew what magnets were — they were things that attracted iron — long before science told them what magnets were. A child learns what the word ‘magnet’ means not, typically, by learning an explicit definition, but by learning the ‘folk physics’ of magnets, in which the ordinary term ‘magnet’ is embedded or implicitly defined as a theoretical term.”

Daniel Dennett, The Intentional Stance, Chap. 3, “Three Kinds of Intentional Psychology”

Here is another characterization of folk psychology:

“Philosophers with a yen for conceptual reform are nowadays prone to describe our ordinary, common sense, Rylean description of the mind as ‘folk psychology,’ the implication being that when we ascribe intentions, beliefs, motives, and emotions to others we are offering explanations of those persons’ behaviour, explanations which belong to a sort of pre-scientific theory.”

Scott M. Christensen and Dale R. Turner, editors, Folk Psychology and the Philosophy of Mind, Chap. 10, “The Very Idea of a Folk Psychology” by Robert A. Sharpe, University of Wales, United Kingdom

There is now quite a considerable literature on folk psychology, and many positions in the philosophy of mind are defined by their relationship to folk psychology — eliminativism is largely the elimination of folk psychology; reductionism is largely the reduction of folk psychology to cognitive science or scientific psychology, and so on. Others have gone on to identify other folk concepts, as, for example, folk biology:

Folk biology is the cognitive study of how people classify and reason about the organic world. Humans everywhere classify animals and plants into species-like groups as obvious to a modern scientist as to a Maya Indian. Such groups are primary loci for thinking about biological causes and relations (Mayr 1969). Historically, they provided a transtheoretical base for scientific biology in that different theories — including evolutionary theory — have sought to account for the apparent constancy of “common species” and the organic processes centering on them. In addition, these preferred groups have “from the most remote period… been classed in groups under groups” (Darwin 1859: 431). This taxonomic array provides a natural framework for inference, and an inductive compendium of information, about organic categories and properties. It is not as conventional or arbitrary in structure and content, nor as variable across cultures, as the assembly of entities into cosmologies, materials, or social groups. From the vantage of EVOLUTIONARY PSYCHOLOGY, such natural systems are arguably routine “habits of mind,” in part a natural selection for grasping relevant and recurrent “habits of the world.”

Robert Andrew Wilson and Frank C. Keil, The MIT Encyclopedia of the Cognitive Sciences

We can easily see that the idea of folk concepts as pre-scientific concepts is applicable throughout all branches of knowledge. This has already been made explicit:

“…there is good evidence that we have or had folk physics, folk chemistry, folk biology, folk botany, and so on. What has happened to these folk endeavors? They seem to have given way to scientific accounts.”

William Andrew Rottschaefer, The Biology and Psychology of Moral Agency, 1998, p. 179.

The simplest reading of the above is that in a pre-scientific state we use pre-scientific concepts, and as the scientific revolution unfolds and begins to transform traditional bodies of knowledge, these pre-scientific folk concepts are replaced with scientific concepts and knowledge becomes scientific knowledge. Thereafter, folk concepts are abandoned (eliminated) or formalized so that they can be systematically located in a scientific body of knowledge. All of this is quite close to the 19th century positivist August Comte’s theory of the three stages of knowledge, according to which theological explanations gave way to metaphysical explanations, which in turn gave way to positive scientific explanations, which demonstrates the continuity of positivist thought — even that philosophical thought that does not recognize itself as being positivist. In each case, an earlier non-scientific mode of thought is gradually replaced by a mature scientific mode of thought.

While this simple replacement model of scientific knowledge has certain advantages, it has a crucial weakness, and this is a weakness shared by all theories that, implicitly or explicitly, assume that the mind and its concepts are static and stagnant. Allow me to once again quote one of my favorite passage from Kurt Gödel, the importance of which I cannot stress enough:

“Turing… gives an argument which is supposed to show that mental procedures cannot go beyond mechanical procedures. However, this argument is inconclusive. What Turing disregards completely is the fact that mind, in its use, is not static, but is constantly developing, i.e., that we understand abstract terms more and more precisely as we go on using them, and that more and more abstract terms enter the sphere of our understanding. There may exist systematic methods of actualizing this development, which could form part of the procedure. Therefore, although at each stage the number and precision of the abstract terms at our disposal may be finite, both (and, therefore, also Turing’s number of distinguishable states of mind) may converge toward infinity in the course of the application of the procedure.”

“Some remarks on the undecidability results” (Italics in original) in Gödel, Kurt, Collected Works, Volume II, Publications 1938-1974, New York and Oxford: Oxford University Press, 1990, p. 306.

Not only does the mind refine its concepts and arrive at more abstract formulations; the mind also introduces wholly new concepts in order to attempt to understand new or hitherto unknown phenomena. In this context, what this means is that we are always introducing new “folk” concepts as our experience expands and diversifies, so that there is not a one-time transition from unscientific folk concepts to scientific concepts, but a continual and ongoing evolution of scientific thought in which folk concepts are introduced, their want of rigor is felt, and more refined and scientific concepts are eventually introduced to address the problem of the folk concepts. But this process can result in the formulation of entirely new sciences, and we must then in turn hazard new “folk” concepts in the attempt to get a handle on this new discipline, however inadequate our first attempts may be to understand some unfamiliar body of knowledge.

For example, before the work of Georg Cantor and Richard Dedekind there was no science of set theory. In formulating set theory, 19th century mathematicians had to introduce a great many novel concepts (set, element, mapping) and mathematical procedures (one-to-one correspondence, diagonalization). These early concepts of set theory are now called “naïve set theory,” which have largely been replaced by (several distinct) axiomatizations of set theory, which have either formalized or eliminated the concepts of naïve set theory, which we might also call “folk” set theory. Nevertheless, many “folk” concepts of set theory persist, and Gödel spent much of his later career attempting to produce better formalizations of the concepts of set theory than those employed in now accepted axiomatizations of set theory.

As civilization has changed, and indeed as civilization emerged, we have had occasion to introduce new terms and concepts in order to describe and explain newly emergent forms of life. The domestication of plants and animals necessitated the introduction of concepts of plant and animal husbandry. The industrial revolution and the macroeconomic forces it loosed upon the world necessitated the introduction of terms and concepts of industry and economics. In each case, non-scientific folk concepts preceded the introduction of scientific concepts explained within a comprehensive theoretical framework. In many cases, our theoretical framework is not yet fully formulated and we are still in a stage of conceptual development that involves the overlapping of folk and scientific concepts.

Given the idea of folk concepts and their replacement by scientific concepts, a mature science could be defined as a science in which all folk concepts have been either formalized, transcended, or eliminated. The infinitistic nature of science mystery (which is discussed in Scientific Curiosity and Existential Need), however, suggests that there will always be sciences in an early and therefore immature stage of development. Our knowledge of the scientific method and the development of science means that we can anticipate scientific developments and understand when our intuitions are inadequate and therefore, in a sense, folk concepts. We have an advantage over the unscientific past that knew nothing of the coming scientific revolution and how it would transform knowledge. But we cannot entirely eliminate folk concepts from the early stages of scientific development, and in so far as our scientific civilization results in continuous scientific development, we will always have sciences in the early stages of development.

Scientific progress, then, does not eliminate folk concepts, but generates new and ever more folk concepts even as it eliminates old and outdated folk concepts.

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