[Paleopsych] Atlantic: Vannevar Bush, "As We May Think" (1945)

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Vannevar Bush, "As We May Think"
The Atlantic Monthly, 1945.7
http://ccat.sas.upenn.edu/~jod/texts/vannevar.bush.html

    As Director of the Office of Scientific Research and Development, Dr.
    Vannevar Bush has coordinated the activities of some six thousand
    leading American scientists in the application of science to warfare.
    In this significant article he holds up an incentive for scientists
    when the fighting has ceased. He urges that men of science should then
    turn to the massive task of making more accessible our bewildering
    store of knowledge. For many years inventions have extended man's
    physical powers rather than the powers of his mind. Trip hammers that
    multiply the fists, microscopes that sharpen the eye, and engines of
    destruction and detection are new results, but the end results, of
    modern science. Now, says Dr. Bush, instruments are at hand which, if
    properly developed, will give man access to and command over the
    inherited knowledge of the ages. The perfection of these pacific
    instruments should be the first objective of our scientists as they
    emerge from their war work. Like Emerson's famous address of 1837 on
    ``The American Scholar,'' this paper by Dr. Bush calls for a new
    relationship between thinking man and the sum of our knowledge. - The
    Editor
      _________________________________________________________________

    This has not been a scientist's war; it has been a war in which all
    have had a part. The scientists, burying their old professional
    competition in the demand of a common cause, have shared greatly and
    learned much. It has been exhilarating to work in effective
    partnership. Now, for many, this appears to be approaching an end.
    What are the scientists to do next?

    For the biologists, and particularly for the medical scientists, there
    can be little indecision, for their war work has hardly required them
    to leave the old paths. Many indeed have been able to carry on their
    war research in their familiar peacetime laboratories. Their
    objectives remain much the same.

    It is the physicists who have been thrown most violently off stride,
    who have left academic pursuits for the making of strange destructive
    gadgets, who have had to devise new methods for their unanticipated
    assignments. They have done their part on the devices that made it
    possible to turn back the enemy. They have worked in combined effort
    with the physicists of our allies. They have felt within themselves
    the stir of achievement. They have been part of a great team. Now, as
    peace approaches, one asks where they will find objectives worthy of
    their best.

I

    Of what lasting benefit has been man's use of science and of the new
    instruments which his research brought into existence? First, they
    have increased his control of his material environment. They have
    improved his food, his clothing, his shelter; they have increased his
    security and released him partly from the bondage of bare existence.
    They have given him increased knowledge of his own biological
    processes so that he has had a progressive freedom from disease and an
    increased span of life. They are illuminating the interactions of his
    physiological and psychological functions, giving the promise of an
    improved mental health.

    Science has provided the swiftest communication between individuals;
    it has provided a record of ideas and has enabled man to manipulate
    and to make extracts from that record so that knowledge evolves and
    endures throughout the life of a race rather than that of an
    individual.

    There is a growing mountain of research. But there is increased
    evidence that we are being bogged down today as specialization
    extends. The investigator is staggered by the findings and conclusions
    of thousands of other workers - conclusions which he cannot find time
    to grasp, much less to remember, as they appear. Yet specialization
    becomes increasingly necessary for progress, and the effort to bridge
    between disciplines is correspondingly superficial.

    Professionally our methods of transmitting and reviewing the results
    of research are generations old and by now are totally inadequate for
    their purpose. If the aggregate time spent in writing scholarly works
    and in reading them could be evaluated, the ratio between these
    amounts of time might well be startling. Those who conscientiously
    attempt to keep abreast of current thought, even in restricted fields,
    by close and continuous reading might well shy away from an
    examination calculated to show how much of the previous month's
    efforts could be produced on call. Mendel's concept of the laws of
    genetics was lost to the world for a generation because his
    publication did not reach the few who were capable of grasping and
    extending it; and this sort of catastrophe is undoubtedly being
    repeated all about us, as truly significant attainments become lost in
    the mass of the inconsequential.

    The difficulty seems to be, not so much that we publish unduly in view
    of the extent and variety of present-day interests, but rather that
    publication has been extended far beyond our present ability to make
    real use of the record. The summation of human experience us being
    expanded at a prodigious rate, and the means we use for threading
    through the consequent maze to the momentarily important item is the
    same as was used in the days of square-rigged ships.

    But there are signs of a change as new and powerful instrumentalities
    come into use. Photocells capable of seeing things in a physical
    sense, advanced photography which can record what is seen or even what
    is not, thermionic tubes capable of controlling potent forces under
    the guidance of less power than a mosquito uses to vibrate his wings,
    cathode ray tubes rendering visible an occurrence so brief that by
    comparison a microsecond is a long time, relay combinations which will
    carry out involved sequences of movements more reliably than any human
    operator and thousand of times as fast - there are plenty of
    mechanical aids with which to effect a transformation in scientific
    records.

    Two centuries ago Leibnitz invented a calculating machine which
    embodied most of the essential features of recent keyboard devices,
    but it could not then come into use. The economics of the situation
    were against it: the labor involved in constructing it, before the
    days of mass production, exceeded the labor to be saved by its use,
    since all it could accomplish could be duplicated by sufficient use of
    pencil and paper. Moreover, it would have been subject to frequent
    breakdown, so that it could not have been depended upon; for at that
    time and long after, complexity and unreliability were synonymous.

    Babbage, even with remarkably generous support for his time, could not
    produce his great arithmetical machine. His idea was sound enough, but
    construction and maintenance costs were then too heavy. Had a Pharaoh
    been given detailed and explicit designs of an automobile, and had he
    understood them completely, it would have taxed the resources of his
    kingdom to have fashioned the thousands of parts for a single car, and
    that car would have broken down on the first trip to Giza.

    Machines with interchangeable parts can now be constructed with great
    economy of effort. In spite of much complexity, they perform reliably.
    Witness the humble typewriter, or the movie camera, or the automobile.
    Electrical contacts have ceased to stick when thoroughly understood.
    Note the automatic telephone exchange, which has hundred of thousands
    of such contacts, and yet is reliable. A spider web of metal, sealed
    in a thin glass container, a wire heated to brilliant glow, in short,
    the thermionic tube of radio sets, is made by the hundred million,
    tossed about in packages, plugged into sockets - and it works! Its
    gossamer parts, the precise location and alignment involved in its
    construction, would have occupied a master craftsman of the guild for
    months; now it is built for thirty cents. The world has arrived at an
    age of cheap complex devices of great reliability; and something is
    bound to come of it.

II

    A record, if it is to be useful to science, must be continuously
    extended, it must be stored, and above all it must be consulted. Today
    we make the record conventionally by writing and photography, followed
    by printing; but we also record on film, on wax disks, and on magnetic
    wires. Even if utterly new recording procedures do not appear, these
    present ones are certainly in the process of modification and
    extension.

    Certainly progress in photography is not going to stop. Faster
    material and lenses, more automatic cameras, finer-grained sensitive
    compounds to allow an extension of the minicamera idea, are all
    imminent. Let us project this trend ahead to a logical, if not
    inevitable, outcome. The camera hound of the future wears on his
    forehead a lump a little larger than a walnut. It takes pictures 3
    millimeters square, later to be projected or enlarged, which after all
    involves only a factor of 10 beyond present practice. The lens is of
    universal focus, down to any distance accommodated by the unaided eye,
    simply because it is of short focal length. There is a built-in
    photocell on the walnut such as we now have on at least one camera,
    which automatically adjusts exposure for a wide range of illumination.
    There is film in the walnut for a hundred exposure, and the spring for
    operating its shutter and shifting its film is wound once for all when
    the film clip is inserted. It produces its result in full color. It
    may well be stereoscopic, and record with spaced glass eyes, for
    striking improvements in stereoscopic technique are just around the
    corner.

    The cord which trips its shutter may reach down a man's sleeve within
    easy reach of his fingers. A quick squeeze, and the picture is taken.
    On a pair of ordinary glasses is a square of fine lines near the top
    of one lens, where it is out of the way of ordinary vision. When an
    object appears in that square, it is lined up for its picture. As the
    scientist of the future moves about the laboratory or the field, every
    time he looks at something worthy of the record, he trips the shutter
    and in it goes, without even an audible click. Is this all fantastic?
    The only fantastic thing about it is the idea of making as many
    pictures as would result from its use.

    Will there be dry photography? It is already here in two forms. When
    Brady made his Civil War pictures, the plate had to be wet at the time
    of exposure. Now it has to be wet during development instead. In the
    future perhaps it need not be wetted at all. There have long been
    films impregnated with diazo dyes which form a picture without
    development, so that it is already there as soon as the camera has
    been operated. An exposure to ammonia gas destroys the unexposed dye,
    and the picture can then be taken out into the light and examined. The
    process is now slow, but someone may speed it up, and it has no grain
    difficulties such as now keep photographic researchers busy. Often it
    would be advantageous to be able to snap the camera and to look at the
    picture immediately.

    Another process now is use is also slow, and more or less clumsy. For
    fifty years impregnated papers have been used which turn dark at every
    point where an electrical contact touches them, by reason of the
    chemical change thus produced in an iodine compound included in the
    paper. They have been used to make records, for a pointer moving
    across them can leave a trail behind. If the electrical potential on
    the pointer is varied as it moves, the line becomes light or dark in
    accordance with the potential.

    This scheme is now used in facsimile transmission. The pointer draws a
    set of closely spaced lines across the paper one after another. As it
    moves, its potential is varied in accordance with a varying current
    received over wires from a distant station, where these variations are
    produced by a photocell which is similarly scanning a picture. At
    every instant the darkness of the line being drawn is made equal to
    the darkness of the point on the picture being observed by the
    photocell. Thus, when the whole picture has been covered, a replica
    appears at the receiving end.

    A scene itself can be just as well looked over line by line by the
    photocell in this way as can a photograph of the scene. This whole
    apparatus constitutes a camera, with the added feature, which can be
    dispensed with if desired, of making its picture at a distance. It is
    slow, and the picture is poor in detail. Still, it does give another
    process of dry photography, in which the picture is finished as soon
    as it is taken.

    It would be a brave man who could predict that such a process will
    always remain clumsy, slow, and faulty in detail. Television equipment
    today transmits sixteen reasonably good images a second, and it
    involves only two essential differences from the process described
    above. For one, the record is made by a moving beam of electrons
    rather than a moving pointer, for the reason that an electron beam can
    sweep across the picture very rapidly indeed. The other difference
    involves merely the use of a screen which glows momentarily when the
    electrons hit, rather than a chemically treated paper or film which is
    permanently altered. This speed is necessary in television, for motion
    pictures rather than stills are the object.

    Use chemically treated film in place of the glowing screen, allow the
    apparatus to transmit one picture rather than a succession, and a
    rapid camera for dry photography results. The treated film needs to be
    far faster in action than present examples, but it probably could be.
    More serious is the objection that this scheme would involve putting
    the film inside a vacuum chamber, for electron beams behave normally
    only in such a rarefied environment. This difficulty could be avoided
    by allowing the electron beam to play on one side of a partition, and
    by pressing the film against the other side, if this partition were
    such as to allow the electrons to go through perpendicular to its
    surface, and to prevent them from spreading out sideways. Such
    partitions, in crude form, could certainly be constructed, and they
    will hardly hold up the general development.

    Like dry photography, microphotography still has a long way to go. The
    basic scheme of reducing the size of the record, and examining it by
    projection rather than directly, has possibilities too great to be
    ignored. The combination of optical projection and photographic
    reduction is already producing some results in microfilm for scholarly
    purposes, and the potentialities are highly suggestive. Today, with
    microfilm, reductions by a linear factor of 20 can be employed and
    still produce full clarity when the material is re-enlarged for
    examination. The limits are set by the graininess of the film, the
    excellence of the optical system, and the efficiency of the light
    sources employed. All of these are rapidly improving.

    Assume a linear ratio of 100 for future use. Consider film of the same
    thickness as paper, although thinner film will certainly be usable.
    Even under these conditions there would be a total factor of 10,000
    between the bulk of the ordinary record on books, and its microfilm
    replica. The Encyclopoedia Britannica could be reduced to the volume
    of a matchbox. A library of a million volumes could be compressed into
    one end of a desk. If the human race has produced since the invention
    of movable type a total record, in the form of magazines, newspapers,
    books, tracts, advertising blurbs, correspondence, having a volume
    corresponding to a billion books, the whole affair, assembled and
    compressed, could be lugged off in a moving van. Mere compression, of
    course, is not enough; one needs not only to make and store a record
    but also to be able to consult it, and this aspect of the matter comes
    later. Even the modern great library is not generally consulted; it is
    nibbled by a few.

    Compression is important, however, when it comes to costs. The
    material for the microfilm Britannica would cost a nickel, and it
    could be mailed anywhere for a cent. What would it cost to print a
    million copies? To print a sheet of newspaper, in a large edition,
    costs a small fraction of a cent. The entire material of the
    Britannica in reduced microfilm form would go on a sheet eight and
    one-half by eleven inches. Once it is available, with the photographic
    reproduction methods of the future, duplicates in large quantities
    could probably be turned out for a cent apiece beyond the cost of
    materials. The preparation of the original copy? That introduces the
    next aspect of the subject.

III

    To make the record, we now push a pencil or tap a typewriter. Then
    comes the process of digestion and correction, followed by an
    intricate process of typesetting, printing, and distribution. To
    consider the first stage of the procedure, will the author of the
    future cease writing by hand or typewriter and talk directly to the
    record? He does so indirectly, by talking to a stenographer or a wax
    cylinder; but the elements are all present if he wishes to have his
    talk directly produce a typed record. All he needs to do us to take
    advantage of existing mechanisms and to alter his language.

    At a recent World Fair a machine called a Voder was shown. A girl
    stroked its keys and it emitted recognizable speech. No human vocal
    cords entered in the procedure at any point; the keys simply combined
    some electrically produced vibrations and passed these on to a
    loud-speaker. In the Bell Laboratories there is the converse of this
    machine, called a Vocoder. The loudspeaker is replaced by a
    microphone, which picks up sound. Speak to it, and the corresponding
    keys move. This may be one element of the postulated system.

    The other element is found in the stenotype, that somewhat
    disconcerting device encountered usually at public meetings. A girl
    strokes its keys languidly and looks about the room and sometimes at
    the speaker with a disquieting gaze. From it emerges a typed strip
    which records in a phonetically simplified language a record of what
    the speaker is supposed to have said. Later this strip is retyped into
    ordinary language, for in its nascent form it is intelligible only to
    the initiated. Combine these two elements, let the Vocoder run the
    stenotype, and the result is a machine which types when talked to.

    Our present languages are not especially adapted to this sort of
    mechanization, it is true. It is strange that the inventors of
    universal languages have not seized upon the idea of producing one
    which better fitted the technique for transmitting and recording
    speech. Mechanization may yet force the issue, especially in the
    scientific field; whereupon scientific jargon would become still less
    intelligible to the layman.

    One can now picture a future investigator in his laboratory. His hands
    are free, and he is not anchored. As he moves about and observes, he
    photographs and comments. Time is automatically recorded to tie the
    two records together. If he goes into the field, he may be connected
    by radio to his recorder. As he ponders over his notes in the evening,
    he again talks his comments into the record. His typed record, as well
    as his photographs, may both be in miniature, so that he projects them
    for examination.

    Much needs to occur, however, between the collection of data and
    observations, the extraction of parallel material from the existing
    record, and the final insertion of new material into the general body
    of the common record. For mature thought there is no mechanical
    substitute. But creative thought and essentially repetitive thought
    are very different things. For the latter there are, and may be,
    powerful mechanical aids.

    Adding a column of figures is a repetitive thought process, and it was
    long ago properly relegated to the machine. True, the machine is
    sometimes controlled by the keyboard, and thought of a sort enters in
    reading the figures and poking the corresponding keys, but even this
    is avoidable. Machines have been made which will read typed figures by
    photocells and then depress the corresponding keys; these are
    combinations of photocells for scanning the type, electric circuits
    for sorting the consequent variations, and relay circuits for
    interpreting the result into the action of solenoids to pull the keys
    down.

    All this complication is needed because of the clumsy way in which we
    have learned to write figures. If we recorded them positionally,
    simply by the configuration of a set of dots on a card, the automatic
    reading mechanism would become comparatively simple. In fact, if the
    dots are holes, we have the punched-card machine long ago produced by
    Hollorith for the purposes of the census, and now used throughout
    business. Some types of complex businesses could hardly operate
    without these machines.

    Adding is only one operation. To perform arithmetical computation
    involves also subtraction, multiplication, and division, and in
    addition some method for temporary storage of results, removal from
    storage for further manipulation, and recording of final results by
    printing. Machines for these purposes are now of two types: keyboard
    machines for accounting and the like, manually controlled for the
    insertion of data, and usually automatically controlled as far as the
    sequence of operations is concerned; and punched-card machines in
    which separate operations are usually delegated to a series of
    machines, and the cards then transferred bodily from one to another.
    Both forms are very useful; but as far as complex computations are
    concerned, both are still embryo.

    Rapid electrical counting appeared soon after the physicists found it
    desirable to count cosmic rays. For their own purposes the physicists
    promptly constructed thermionic-tube equipment capable of counting
    electrical impulses at the rate of 100,000 a second. The advanced
    arithmetical machines of the future will be electrical in nature, and
    they will perform at 100 times present speeds, or more.

    Moreover, they will be far more versatile than present commercial
    machines, so that they may readily be adapted for a wide variety of
    operations. They will be controlled by a control card or film, they
    will select their own data and manipulate it in accordance with the
    instructions thus inserted, they will perform complex arithmetical
    computations at exceedingly high speeds, and they will record results
    in such form as to be readily available for distribution or for later
    further manipulation. Such machines will have enormous appetites. One
    of them will take instructions and data from a roomful of girls armed
    with simple keyboard punches, and will deliver sheets of computed
    results every few minutes. There will always be plenty of things to
    compute in the detailed affairs of millions of people doing
    complicated things.

IV

    The repetitive processes of thought are not confined, however, to
    matters of arithmetic and statistics. In fact, every time one combines
    and records facts in accordance with established logical processes,
    the creative aspect of thinking is concerned only with the selection
    of the data and the process to be employed, and the manipulation
    thereafter is repetitive in nature and hence a fit matter to be
    relegated to the machines. Not so much has been done along these
    lines, beyond the bounds of arithmetic, as might be done, primarily
    because of the economics of the situation. The needs of business, and
    the extensive market obviously waiting, assured the advent of
    mass-produced arithmetical machines just as soon as production methods
    were sufficiently advanced.

    With machines for advanced analysis no such situation existed; for
    there was and is no extensive market; the users of advanced methods of
    manipulating data are a very small part of the population. There are,
    however, machines for solving differential equations - and functional
    and integral equations, for that matter. There are many special
    machines, such as the harmonic synthesizer which predicts the tides.
    There will be many more, appearing certainly first in the hands of the
    scientist and in small numbers.

    If scientific reasoning were limited to the logical processes of
    arithmetic, we should not get far in our understanding of the physical
    world. One might as well attempt to grasp the game of poker entirely
    by the use of the mathematics of probability. The abacus, with its
    beads string on parallel wires, led the Arabs to positional numeration
    and the concept of zero many centuries before the rest of the world;
    and it was a useful tool - so useful that it still exists.

    It is a far cry from the abacus to the modern keyboard accounting
    machine. It will be an equal step to the arithmetical machine of the
    future. But even this new machine will not take the scientist where he
    needs to go. Relief must be secured from laborious detailed
    manipulation of higher mathematics as well, if the users of it are to
    free their brains for something more than repetitive detailed
    transformations in accordance with established rules. A mathematician
    is not a man who can readily manipulate figures; often he cannot. He
    is not even a man who can readily perform the transformation of
    equations by the use of calculus. He is primarily an individual who is
    skilled in the use of symbolic logic on a high plane, and especially
    he is a man of intuitive judgment in the choice of the manipulative
    processes he employs.

    All else he should be able to turn over to his mechanism, just as
    confidently as he turns over the propelling of his car to the
    intricate mechanism under the hood. Only then will mathematics be
    practically effective in bringing the growing knowledge of atomistics
    to the useful solution of the advanced problems of chemistry,
    metallurgy, and biology. For this reason there will come more machines
    to handle advanced mathematics for the scientist. Some of them will be
    sufficiently bizarre to suit the most fastidious connoisseur of the
    present artifacts of civilization.

V

    The scientist, however, is not the only person who manipulates data
    and examines the world about him by the use of logical processes,
    although he sometimes preserves this appearance by adopting into the
    fold anyone who becomes logical, much in the manner in which a British
    labor leader is elevated to knighthood. Whenever logical processes of
    thought are employed - that is, whenever thought for a time runs along
    an accepted groove - there is an opportunity for the machine. Formal
    logic used to be a keen instrument in the hands of the teacher in his
    trying of students' souls. It is readily possible to construct a
    machine which will manipulate premises in accordance with formal
    logic, simply by the clever use of relay circuits. Put a set of
    premises into such a device and turn the crank, and it will readily
    pass out conclusion after conclusion, all in accordance with logical
    law, and with no more slips than would be expected of a keyboard
    adding machine.

    Logic can become enormously difficult, and it would undoubtedly be
    well to produce more assurance in its use. The machines for higher
    analysis have usually been equation solvers. Ideas are beginning to
    appear for equation transformers, which will rearrange the
    relationship expressed by an equation in accordance with strict and
    rather advanced logic. Progress is inhibited by the exceedingly crude
    way in which mathematicians express their relationships. They employ a
    symbolism which grew like Topsy and has little consistency; a strange
    fact in that most logical field.

    A new symbolism, probably positional, must apparently precede the
    reduction of mathematical transformations to machine processes. Then,
    on beyond the strict logic of the mathematician, lies the application
    of logic in everyday affairs. We may some day click off arguments on a
    machine with the same assurance that we now enter sales on a cash
    register. But the machine of logic will not look like a cash register,
    even a streamlined model.

    So much for the manipulation of ideas and their insertion into the
    record. Thus far we seem to be worse off than before - for we can
    enormously extend the record; yet even in its present bulk we can
    hardly consult it. This is a much larger matter than merely the
    extraction of data for the purposes of scientific research; it
    involves the entire process by which man profits by his inheritance of
    acquired knowledge. The prime action of use is selection, and here we
    are halting indeed. There may be millions of fine thoughts, and the
    account of the experience on which they are based, all encased within
    stone walls of acceptable architectural form; but if the scholar can
    get at only one a week by diligent search, his syntheses are not
    likely to keep up with the current scene.

    Selection, in this broad sense, is a stone adze in the hands of a
    cabinetmaker. Yet, in a narrow sense and in other areas, something has
    already been done mechanically on selection. The personnel officer of
    a factory drops a stack of a few thousand employee cards into a
    selecting machine, sets a code in accordance with an established
    convention, and produces in a short time a list of all employees who
    live in Trenton and know Spanish. Even such devices are much too slow
    when it comes, for example, to matching a set of fingerprints with one
    of five millions on file. Selection devices of this sort will soon be
    speeded up from their present rate of reviewing data at a few hundred
    a minute. By the use of photocells and microfilm they will survey
    items at the rate of thousands a second, and will print out duplicates
    of those selected.

    This process, however, is simple selection: it proceeds by examining
    in turn every one of a large set of items, and by picking out those
    which have certain specified characteristics. There is another form of
    selection best illustrated by the automatic telephone exchange. You
    dial a number and the machine selects and connects just one of a
    million possible stations. It does not run over them all. It pays
    attention only to a class given by a first digit, and so on; and thus
    proceeds rapidly and almost unerringly to the selected station. It
    requires a few seconds to make the selection, although the process
    could be speeded up if increased speed were economically warranted. If
    necessary, it could be made extremely fast by substituting
    thermionic-tube switching for mechanical switching, so that the full
    selection could be made in one-hundredth of a second. No one would
    wish to spend the money necessary to make this change in the telephone
    system, but the general idea is applicable elsewhere.

    Take the prosaic problem of the great department store. Every time a
    charge sale is made, there are a number of things to be done. The
    inventory needs to be revised, the salesman needs to be given credit
    for the sale, the general accounts need an entry, and, most important,
    the customer needs to be charged. A central records device has been
    developed in which much of this work is done conveniently. The
    salesman places on a stand the customer's identification card, his own
    card, and the card taken from the article sold - all punched cards.
    When he pulls a lever, contacts are made through the holes, machinery
    at a central point makes the necessary computations and entries, and
    the proper receipt is printed for the salesman to pass to the
    customer.

    But there may be ten thousand charge customers doing business with the
    store, and before the full operation can be completed someone has to
    select the right card and insert it at the central office. Now rapid
    selection can slide just the proper card into position in an instant
    or two, and return it afterward. Another difficulty occurs, however.
    Someone must read a total on the card, so that the machine can add its
    computed item to it. Conceivably the cards might be of the dry
    photography type I have described. Existing totals could then be read
    by photocell, and the new total entered by an electron beam.

    The cards may be in miniature, so that they occupy little space. They
    must move quickly. They need not be transferred far, but merely into
    position so that the photocell and recorder can operate on them.
    Positional dots can enter the data. At the end of the month a machine
    can readily be made to read these and to print an ordinary bill. With
    tube selection, in which no mechanical parts are involved in the
    switches, little time need be occupied in bringing the correct card
    into use - a second should suffice for the entire operation. The whole
    record on the card may be made by magnetic dots on a steel sheet if
    desired, instead of dots to be observed optically, following the
    scheme by which Poulsen long ago put speech on a magnetic wire. This
    method has the advantage of simplicity and ease of erasure. By using
    photography, however, one can arrange to project the record in
    enlarged form, and at a distance by using the process common in
    television equipment.

    One can consider rapid selection of this form, and distant projection
    for other purposes. To be able to key one sheet of a million before an
    operator in a second or two, with the possibility of then adding notes
    thereto, is suggestive in many ways. It might even be of use in
    libraries, but that is another story. At any rate, there are now some
    interesting combinations possible. One might, for example, speak to a
    microphone, in the manner described in connection with the
    speech-controlled typewriter, and thus make his selections. It would
    certainly beat the usual file clerk.

VI

    The real heart of the matter of selection, however, goes deeper than a
    lag in the adoption of mechanisms by libraries, or a lack of
    development of devices for their use. Our ineptitude in getting at the
    record is largely caused by the artificiality of systems of indexing.
    When data of any sort are placed in storage, they are filed
    alphabetically or numerically, and information is found (when it is)
    by tracing it down from subclass to subclass. It can be in only one
    place, unless duplicates are used; one has to have rules as to which
    path will locate it, and the rules are cumbersome. Having found one
    item, moreover, one has to emerge from the system and re-enter on a
    new path.

    The human mind does not work that way. It operates by association.
    With one item in its grasp, it snaps instantly to the next that is
    suggested by the association of thoughts, in accordance with some
    intricate web of trails carried by the cells of the brain. It has
    other characteristics, of course; trails that are not frequently
    followed are prone to fade, items are not fully permanent, memory is
    transitory. Yet the speed of action, the intricacy of trails, the
    detail of mental pictures, is awe-inspiring beyond all else in nature.

    Man cannot hope fully to duplicate this mental process artificially,
    but he certainly ought to be able to learn from it. In minor ways he
    may even improve, for his record have relative permanency. The first
    idea, however, to be drawn from the analogy concerns selection.
    Selection by association, rather than by indexing, may yet be
    mechanized. One cannot hope thus to equal the speed and flexibility
    with which the mind follows an associative trail, but it should be
    possible to beat the mind decisively in regard to the permanence and
    clarity of the items resurrected from storage.

    Consider a future device for individual use, which is a sort of
    mechanized private file and library. It needs a name, and to coin one
    at random, ``memex'' will do. A memex is a device in which an
    individual stores all his books, records, and communications, and
    which is mechanized so that it may be consulted with exceeding speed
    and flexibility. It is an enlarged intimate supplement to his memory.

    It consists of a desk, and while it can presumably be operated from a
    distance, it is primarily the piece of furniture at which he works. On
    the top are slanting translucent screens, on which material can be
    projected for convenient reading. There is a keyboard, and sets of
    buttons and levers. Otherwise it looks like an ordinary desk.

    In one end is the stored material. The matter of bulk is well taken
    care of by improved microfilm. Only a small part of the interior of
    the memex is devoted to storage, the rest to mechanism. Yet if the
    user inserted 5000 pages of material a day it would take him hundreds
    of years to fill the repository, so he can be profligate and enter
    material freely.

    Most of the memex contents are purchased on microfilm ready for
    insertion. Books of all sorts, pictures, current periodicals,
    newspapers, are thus obtained and dropped into place. Business
    correspondence takes the same path. And there is provision for direct
    entry. On the top of the memex is a transparent platen. On this are
    placed longhand notes, photographs, memoranda, all sort of things.
    When one is in place, the depression of a lever causes it to be
    photographed onto the next blank space in a section of the memex film,
    dry photography being employed.

    There is, of course, provision for consultation of the record by the
    usual scheme of indexing. If the user wishes to consult a certain
    book, he taps its code on the keyboard, and the title page of the book
    promptly appears before him, projected onto one of his viewing
    positions. Frequently-used codes are mnemonic, so that he seldom
    consults his code book; but when he does, a single tap of a key
    projects it for his use. Moreover, he has supplemental levers. On
    deflecting one of these levers to the right he runs through the book
    before him, each page in turn being projected at a speed which just
    allows a recognizing glance at each. If he deflects it further to the
    right, he steps through the book 10 pages at a time; still further at
    100 pages at a time. Deflection to the left gives him the same control
    backwards.

    A special button transfers him immediately to the first page of the
    index. Any given book of his library can thus be called up and
    consulted with far greater facility than if it were taken from a
    shelf. As he has several projection positions, he can leave one item
    in position while he calls up another. He can add marginal notes and
    comments, taking advantage of one possible type of dry photography,
    and it could even be arranged so that he can do this by a stylus
    scheme, such as is now employed in the telautograph seen in railroad
    waiting rooms, just as though he had the physical page before him.

VII

    All this is conventional, except for the projection forward of
    present-day mechanisms and gadgetry. If affords an immediate step,
    however, to associative indexing, the basic idea of which is a
    provision whereby any item may be caused at will to select immediately
    and automatically another. This is the essential feature of the memex.
    The process of tying two items together is the important thing.

    When the user is building a trail, he names it, inserts the name in
    his code book, and taps it out on his keyboard. Before him are the two
    items to be joined, projected onto adjacent viewing positions. At the
    bottom of each there are a number of blank code spaces, and a pointer
    is set to indicate one of these on each item. The user taps a single
    key, and the items are permanently joined. In each code space appears
    the code word. Out of view, but also in the code space, is inserted a
    set of dots for photocell viewing; and on each item these dots by
    their positions designate the index number of the other item.

    Thereafter, at any time, when one of these items is in view, the other
    can be instantly recalled merely by tapping a button below the
    corresponding code space. Moreover, when numerous items have been thus
    joined together to form a trail, they can be reviewed in turn, rapidly
    or slowly, by deflecting a lever like that used for turning the pages
    of a book. It is exactly as though the physical items had been
    gathered together to form a new book. It is more than this, for any
    item can be joined into numerous trails.

    The owner of the memex, let us say, is interested in the origin and
    properties of the bow and arrow. Specifically he is studying why the
    short Turkish bow was apparently superior to the English long bow in
    the skirmishes of the Crusades. He has dozens of possibly pertinent
    books and articles in his memex. First he runs through an
    encyclopedia, finds and interesting but sketchy article, leaves it
    projected, Next, in a history, he finds another pertinent item, and
    ties the two together. Thus he goes, building a trail of many items.
    Occasionally he inserts a comment of his own, either linking it into
    the main trail or joining it by a side trail to a particular item.
    When it becomes evident that the elastic properties of available
    materials had a great deal to do with the bow, he branches off on a
    side trail which takes him through textbooks on elasticity and tables
    of physical constants. He inserts a page of longhand analysis of his
    own. Thus he builds a trail of his interest through the maze of
    materials available to him.

    And his trails do not fade. Several years later, his talk with a
    friend turns to the queer ways in which a people resist innovations,
    even of vital interest. He has an example, in the fact that the
    outranged Europeans still failed to adopt the Turkish bow. In fact he
    has a trail on it. A touch brings up the code book. Tapping a few keys
    projects the head of the trail. A lever runs through it at will,
    stopping at interesting items, going off on side excursions. It is an
    interesting trail, pertinent to the discussion. So he sets a
    reproducer in action, photographs the whole trail out, and passes it
    to his friend for insertion in his own memex, there to be linked into
    the more general trail.

VIII

    Wholly new forms of encyclopedias will appear, ready-made with a mesh
    of associative trails running through them, ready to be dropped into
    the memex and there amplified. The lawyer has at his touch the
    associated opinions and decisions of his whole experience, and of the
    experience of friends and authorities. The patent attorney has on call
    the millions of issued patents, with familiar trails to every point of
    his client's interest. The physician, puzzled by its patient's
    reactions, strikes the trail established in studying an earlier
    similar case, and runs rapidly through analogous case histories, with
    side references to the classics for the pertinent anatomy and
    histology. The chemist, struggling with the synthesis of an organic
    compound, has all the chemical literature before him in his
    laboratory, with trails following the analogies of compounds, and side
    trails to their physical and chemical behavior.

    The historian, with a vast chronological account of a people,
    parallels it with a skip trail which stops only at the salient items,
    and can follow at any time contemporary trails which lead him all over
    civilization at a particular epoch. There is a new profession of trail
    blazers, those who find delight in the task of establishing useful
    trails through the enormous mass of the common record. The inheritance
    from the master becomes, not only his additions to the world's record,
    but for his disciples the entire scaffolding by which they were
    erected.

    Thus science may implement the ways in which man produces, stores, and
    consults the record of the race. It might be striking to outline the
    instrumentalities of the future more spectacularly, rather than to
    stick closely to the methods and elements now known and undergoing
    rapid development, as has been done here. Technical difficulties of
    all sorts have been ignored, certainly, but also ignored are means as
    yet unknown which may come any day to accelerate technical progress as
    violently as did the advent of the thermionic tube. In order that the
    picture may not be too commonplace, by reason of sticking to
    present-day patterns, it may be well to mention one such possibility,
    not to prophesy but merely to suggest, for prophecy based on extension
    of the known has substance, while prophecy founded on the unknown is
    only a doubly involved guess.

    All our steps in creating or absorbing material of the record proceed
    through one of the senses - the tactile when we touch keys, the oral
    when we speak or listen, the visual when we read. Is it not possible
    that some day the path may be established more directly?

    We know that when the eye sees, all the consequent information is
    transmitted to the brain by means of electrical vibrations in the
    channel of the optic nerve. This is an exact analogy with the
    electrical vibrations which occur in the cable of a television set:
    they convey the picture from the photocells which see it to the radio
    transmitter from which it is broadcast. We know further that if we can
    approach that cable with the proper instruments, we do not need to
    touch it; we can pick up those vibrations by electrical induction and
    thus discover and reproduce the scene which is being transmitted, just
    as a telephone wire may be tapped for its message.

    The impulse which flow in the arm nerves of a typist convey to her
    fingers the translated information which reaches her eye or ear, in
    order that the fingers may be caused to strike the proper keys. Might
    not these currents be intercepted, either in the original form in
    which information is conveyed to the brain, or in the marvelously
    metamorphosed form in which they then proceed to the hand?

    By bone conduction we already introduce sounds into the nerve channels
    of the deaf in order that they may hear. Is it not possible that we
    may learn to introduce them without the present cumbersomeness of
    first transforming electrical vibrations to mechanical ones, which the
    human mechanism promptly transforms back to the electrical form? With
    a couple of electrodes on the skull the encephalograph now produces
    pen-and-ink traces which bear some relation to the electrical
    phenomena going on in the brain itself. True, the record is
    unintelligible, except as it points out certain gross misfunctioning
    of the cerebral mechanism; but who would now place bounds on where
    such a thing may lead?

    In the outside world, all forms of intelligence, whether of sound or
    sight, have been reduced to the form of varying currents in an
    electric circuit in order that they may be transmitted. Inside the
    human frame exactly the same sort of process occurs. Must we always
    transform to mechanical movements in order to proceed from one
    electrical phenomenon to another? It is a suggestive thought, but it
    hardly warrants prediction without losing touch with reality and
    immediateness.

    Presumably man's spirit should be elevated if he can better review his
    shady past and analyze more completely and objectively his present
    problems. He has built a civilization so complex that he needs to
    mechanize his record more fully if he is to push his experiment to its
    logical conclusion and not merely become bogged down part way there by
    overtaxing his limited memory. His excursion may be more enjoyable if
    he can reacquire the privilege of forgetting the manifold things he
    does not need to have immediately at hand, with some assurance that he
    can find them again if they prove important.

    The applications of science have built man a well-supplied house, and
    are teaching him to live healthily therein. They have enabled him to
    throw masses of people against another with cruel weapons. They may
    yet allow him truly to encompass the great record and to grow in the
    wisdom of race experience. He may perish in conflict before he learns
    to wield that record for his true good. Yet, in the application of
    science to the needs and desires of man, it would seem to be a
    singularly unfortunate stage at which to terminate the process, or to
    lose hope as to the outcome.

[Thanks to John for this.]