---------------------------------------------------------------------- This article was originally published in the July 1945 issue of TheAtlantic Monthly. It is reproduced here with their permission. The electronic version was prepared by Denys Duchier, April 1994.Please email comments and corrections to dduchier@csi.uottawa.ca. ---------------------------------------------------------------------- As Director of the Office of Scientific Research and Development, Dr.Vannevar Bush has coordinated the activities of some six thousandleading American scientists in the application of science to warfare.In this significant article he holds up an incentive for scientistswhen the fighting has ceased. He urges that men of science shouldthen turn to the massive task of making more accessible ourbewildering store of knowledge. For many years inventions haveextended man's physical powers rather than the powers of his mind.Trip hammers that multiply the fists, microscopes that sharpen theeye, and engines of destruction and detection are new results, but theend results, of modern science. Now, says Dr. Bush, instruments areat hand which, if properly developed, will give man access to andcommand over the inherited knowledge of the ages. The perfection ofthese pacific instruments should be the first objective of ourscientists as they emerge from their war work. Like Emerson's famousaddress of 1837 on ``The American Scholar,'' this paper by Dr. Bushcalls for a new relationship between thinking man and the sum of ourknowledge. - The Editor ---------------------------------------------------------------------- This has not been a scientist's war; it has been a war in which allhave had a part. The scientists, burying their old professionalcompetition in the demand of a common cause, have shared greatly andlearned much. It has been exhilarating to work in effectivepartnership. 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, therecan be little indecision, for their war work has hardly required themto leave the old paths. Many indeed have been able to carry on theirwar research in their familiar peacetime laboratories. Theirobjectives 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 destructivegadgets, who have had to devise new methods for their unanticipatedassignments. They have done their part on the devices that made itpossible to turn back the enemy. They have worked in combined effortwith the physicists of our allies. They have felt within themselvesthe stir of achievement. They have been part of a great team. Now,as peace approaches, one asks where they will find objectives worthyof their best. 1 Of what lasting benefit has been man's use of science and of the newinstruments which his research brought into existence? First, theyhave increased his control of his material environment. They haveimproved his food, his clothing, his shelter; they have increased hissecurity and released him partly from the bondage of bare existence.They have given him increased knowledge of his own biologicalprocesses so that he has had a progressive freedom from disease and anincreased span of life. They are illuminating the interactions of hisphysiological and psychological functions, giving the promise of animproved mental health. Science has provided the swiftest communication between individuals;it has provided a record of ideas and has enabled man to manipulateand to make extracts from that record so that knowledge evolves andendures throughout the life of a race rather than that of anindividual. There is a growing mountain of research. But there is increasedevidence that we are being bogged down today as specializationextends. The investigator is staggered by the findings andconclusions of thousands of other workers - conclusions which hecannot find time to grasp, much less to remember, as they appear. Yetspecialization becomes increasingly necessary for progress, and theeffort to bridge between disciplines is correspondingly superficial. Professionally our methods of transmitting and reviewing the resultsof research are generations old and by now are totally inadequate fortheir purpose. If the aggregate time spent in writing scholarly worksand in reading them could be evaluated, the ratio between theseamounts of time might well be startling. Those who conscientiouslyattempt to keep abreast of current thought, even in restricted fields,by close and continuous reading might well shy away from anexamination calculated to show how much of the previous month'sefforts could be produced on call. Mendel's concept of the laws ofgenetics was lost to the world for a generation because hispublication did not reach the few who were capable of grasping andextending it; and this sort of catastrophe is undoubtedly beingrepeated all about us, as truly significant attainments become lost inthe mass of the inconsequential. The difficulty seems to be, not so much that we publish unduly in viewof the extent and variety of present-day interests, but rather thatpublication has been extended far beyond our present ability to makereal use of the record. The summation of human experience is beingexpanded at a prodigious rate, and the means we use for threadingthrough the consequent maze to the momentarily important item is thesame as was used in the days of square-rigged ships. But there are signs of a change as new and powerful instrumentalitiescome into use. Photocells capable of seeing things in a physicalsense, advanced photography which can record what is seen or even whatis not, thermionic tubes capable of controlling potent forces underthe guidance of less power than a mosquito uses to vibrate his wings,cathode ray tubes rendering visible an occurrence so brief that bycomparison a microsecond is a long time, relay combinations which willcarry out involved sequences of movements more reliably than any humanoperator and thousand of times as fast - there are plenty ofmechanical aids with which to effect a transformation in scientificrecords. Two centuries ago Leibnitz invented a calculating machine whichembodied most of the essential features of recent keyboard devices,but it could not then come into use. The economics of the situationwere against it: the labor involved in constructing it, before thedays of mass production, exceeded the labor to be saved by its use,since all it could accomplish could be duplicated by sufficient use ofpencil and paper. Moreover, it would have been subject to frequentbreakdown, so that it could not have been depended upon; for at thattime and long after, complexity and unreliability were synonymous. Babbage, even with remarkably generous support for his time, could notproduce his great arithmetical machine. His idea was sound enough,but construction and maintenance costs were then too heavy. Had aPharaoh been given detailed and explicit designs of an automobile, andhad he understood them completely, it would have taxed the resourcesof his kingdom to have fashioned the thousands of parts for a singlecar, and that car would have broken down on the first trip to Giza. Machines with interchangeable parts can now be constructed with greateconomy 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 thousandsof such contacts, and yet is reliable. A spider web of metal, sealedin 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! Itsgossamer parts, the precise location and alignment involved in itsconstruction, would have occupied a master craftsman of the guild formonths; now it is built for thirty cents. The world has arrived at anage of cheap complex devices of great reliability; and something isbound to come of it. 2 A record, if it is to be useful to science, must be continuouslyextended, 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 onmagnetic wires. Even if utterly new recording procedures do notappear, these present ones are certainly in the process ofmodification and extension. Certainly progress in photography is not going to stop. Fastermaterial and lenses, more automatic cameras, finer-grained sensitivecompounds to allow an extension of the minicamera idea, are allimminent. Let us project this trend ahead to a logical, if notinevitable, outcome. The camera hound of the future wears on hisforehead a lump a little larger than a walnut. It takes pictures 3millimeters square, later to be projected or enlarged, which after allinvolves only a factor of 10 beyond present practice. The lens is ofuniversal focus, down to any distance accommodated by the unaided eye,simply because it is of short focal length. There is a built-inphotocell 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 exposures, and the spring foroperating its shutter and shifting its film is wound once for all whenthe film clip is inserted. It produces its result in full color. Itmay well be stereoscopic, and record with spaced glass eyes, forstriking improvements in stereoscopic technique are just around thecorner. The cord which trips its shutter may reach down a man's sleeve withineasy 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 topof one lens, where it is out of the way of ordinary vision. When anobject appears in that square, it is lined up for its picture. As thescientist of the future moves about the laboratory or the field, everytime he looks at something worthy of the record, he trips the shutterand in it goes, without even an audible click. Is this all fantastic?The only fantastic thing about it is the idea of making as manypictures as would result from its use. Will there be dry photography? It is already here in two forms. WhenBrady made his Civil War pictures, the plate had to be wet at the timeof exposure. Now it has to be wet during development instead. In thefuture perhaps it need not be wetted at all. There have long beenfilms impregnated with diazo dyes which form a picture withoutdevelopment, so that it is already there as soon as the camera hasbeen 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 nograin difficulties such as now keep photographic researchers busy.Often it would be advantageous to be able to snap the camera and tolook at the picture immediately. Another process now in use is also slow, and more or less clumsy. Forfifty years impregnated papers have been used which turn dark at everypoint where an electrical contact touches them, by reason of thechemical change thus produced in an iodine compound included in thepaper. They have been used to make records, for a pointer movingacross them can leave a trail behind. If the electrical potential onthe pointer is varied as it moves, the line becomes light or dark inaccordance with the potential. This scheme is now used in facsimile transmission. The pointer drawsa set of closely spaced lines across the paper one after another. Asit moves, its potential is varied in accordance with a varying currentreceived over wires from a distant station, where these variations areproduced by a photocell which is similarly scanning a picture. Atevery instant the darkness of the line being drawn is made equal tothe darkness of the point on the picture being observed by thephotocell. Thus, when the whole picture has been covered, a replicaappears at the receiving end. A scene itself can be just as well looked over line by line by thephotocell in this way as can a photograph of the scene. This wholeapparatus constitutes a camera, with the added feature, which can bedispensed with if desired, of making its picture at a distance. It isslow, and the picture is poor in detail. Still, it does give anotherprocess of dry photography, in which the picture is finished as soonas it is taken. It would be a brave man who could predict that such a process willalways remain clumsy, slow, and faulty in detail. Televisionequipment today transmits sixteen reasonably good images a second, andit involves only two essential differences from the process describedabove. For one, the record is made by a moving beam of electronsrather than a moving pointer, for the reason that an electron beam cansweep across the picture very rapidly indeed. The other differenceinvolves merely the use of a screen which glows momentarily when theelectrons hit, rather than a chemically treated paper or film which ispermanently altered. This speed is necessary in television, formotion pictures rather than stills are the object. Use chemically treated film in place of the glowing screen, allow theapparatus to transmit one picture rather than a succession, and arapid camera for dry photography results. The treated film needs tobe far faster in action than present examples, but it probably couldbe. More serious is the objection that this scheme would involveputting the film inside a vacuum chamber, for electron beams behavenormally only in such a rarefied environment. This difficulty couldbe avoided by allowing the electron beam to play on one side of apartition, and by pressing the film against the other side, if thispartition were such as to allow the electrons to go throughperpendicular to its surface, and to prevent them from spreading outsideways. Such partitions, in crude form, could certainly beconstructed, 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 itby projection rather than directly, has possibilities too great to beignored. The combination of optical projection and photographicreduction is already producing some results in microfilm for scholarlypurposes, and the potentialities are highly suggestive. Today, withmicrofilm, reductions by a linear factor of 20 can be employed andstill produce full clarity when the material is re-enlarged forexamination. The limits are set by the graininess of the film, theexcellence of the optical system, and the efficiency of the lightsources employed. All of these are rapidly improving. Assume a linear ratio of 100 for future use. Consider film of thesame thickness as paper, although thinner film will certainly beusable. Even under these conditions there would be a total factor of10,000 between the bulk of the ordinary record on books, and itsmicrofilm replica. The Encyclopoedia Britannica could be reduced tothe volume of a matchbox. A library of a million volumes could becompressed into one end of a desk. If the human race has producedsince the invention of movable type a total record, in the form ofmagazines, newspapers, books, tracts, advertising blurbs,correspondence, having a volume corresponding to a billion books, thewhole affair, assembled and compressed, could be lugged off in amoving van. Mere compression, of course, is not enough; one needs notonly to make and store a record but also to be able to consult it, andthis aspect of the matter comes later. Even the modern great libraryis not generally consulted; it is nibbled by a few. Compression is important, however, when it comes to costs. Thematerial for the microfilm Britannica would cost a nickel, and itcould be mailed anywhere for a cent. What would it cost to print amillion copies? To print a sheet of newspaper, in a large edition,costs a small fraction of a cent. The entire material of theBritannica in reduced microfilm form would go on a sheet eight andone-half by eleven inches. Once it is available, with thephotographic reproduction methods of the future, duplicates in largequantities could probably be turned out for a cent apiece beyond thecost of materials. The preparation of the original copy? Thatintroduces the next aspect of the subject. 3 To make the record, we now push a pencil or tap a typewriter. Thencomes the process of digestion and correction, followed by anintricate process of typesetting, printing, and distribution. Toconsider the first stage of the procedure, will the author of thefuture cease writing by hand or typewriter and talk directly to therecord? He does so indirectly, by talking to a stenographer or a waxcylinder; but the elements are all present if he wishes to have histalk directly produce a typed record. All he needs to do is to takeadvantage of existing mechanisms and to alter his language. At a recent World Fair a machine called a Voder was shown. A girlstroked its keys and it emitted recognizable speech. No human vocalcords entered in the procedure at any point; the keys simply combinedsome electrically produced vibrations and passed these on to aloud-speaker. In the Bell Laboratories there is the converse of thismachine, called a Vocoder. The loudspeaker is replaced by amicrophone, which picks up sound. Speak to it, and the correspondingkeys move. This may be one element of the postulated system. The other element is found in the stenotype, that somewhatdisconcerting device encountered usually at public meetings. A girlstrokes its keys languidly and looks about the room and sometimes atthe speaker with a disquieting gaze. From it emerges a typed stripwhich records in a phonetically simplified language a record of whatthe speaker is supposed to have said. Later this strip is retypedinto ordinary language, for in its nascent form it is intelligibleonly to the initiated. Combine these two elements, let the Vocoderrun the stenotype, and the result is a machine which types when talkedto. Our present languages are not especially adapted to this sort ofmechanization, it is true. It is strange that the inventors ofuniversal languages have not seized upon the idea of producing onewhich better fitted the technique for transmitting and recordingspeech. Mechanization may yet force the issue, especially in thescientific field; whereupon scientific jargon would become still lessintelligible to the layman. One can now picture a future investigator in his laboratory. Hishands are free, and he is not anchored. As he moves about andobserves, he photographs and comments. Time is automatically recordedto tie the two records together. If he goes into the field, he may beconnected by radio to his recorder. As he ponders over his notes inthe evening, he again talks his comments into the record. His typedrecord, as well as his photographs, may both be in miniature, so thathe projects them for examination. Much needs to occur, however, between the collection of data andobservations, the extraction of parallel material from the existingrecord, and the final insertion of new material into the general bodyof the common record. For mature thought there is no mechanicalsubstitute. But creative thought and essentially repetitive thoughtare 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 waslong ago properly relegated to the machine. True, the machine issometimes controlled by the keyboard, and thought of a sort enters inreading the figures and poking the corresponding keys, but even thisis avoidable. Machines have been made which will read typed figuresby photocells and then depress the corresponding keys; these arecombinations of photocells for scanning the type, electric circuitsfor sorting the consequent variations, and relay circuits forinterpreting the result into the action of solenoids to pull the keysdown. All this complication is needed because of the clumsy way in which wehave learned to write figures. If we recorded them positionally,simply by the configuration of a set of dots on a card, the automaticreading mechanism would become comparatively simple. In fact, if thedots are holes, we have the punched-card machine long ago produced byHollorith for the purposes of the census, and now used throughoutbusiness. Some types of complex businesses could hardly operatewithout these machines. Adding is only one operation. To perform arithmetical computationinvolves also subtraction, multiplication, and division, and inaddition some method for temporary storage of results, removal fromstorage for further manipulation, and recording of final results byprinting. Machines for these purposes are now of two types: keyboardmachines for accounting and the like, manually controlled for theinsertion of data, and usually automatically controlled as far as thesequence of operations is concerned; and punched-card machines inwhich separate operations are usually delegated to a series ofmachines, and the cards then transferred bodily from one to another.Both forms are very useful; but as far as complex computations areconcerned, both are still embryo. Rapid electrical counting appeared soon after the physicists found itdesirable to count cosmic rays. For their own purposes the physicistspromptly constructed thermionic-tube equipment capable of countingelectrical impulses at the rate of 100,000 a second. The advancedarithmetical machines of the future will be electrical in nature, andthey will perform at 100 times present speeds, or more. Moreover, they will be far more versatile than present commercialmachines, so that they may readily be adapted for a wide variety ofoperations. They will be controlled by a control card or film, theywill select their own data and manipulate it in accordance with theinstructions thus inserted, they will perform complex arithmeticalcomputations at exceedingly high speeds, and they will record resultsin such form as to be readily available for distribution or for laterfurther manipulation. Such machines will have enormous appetites.One of them will take instructions and data from a roomful of girlsarmed with simple keyboard punches, and will deliver sheets ofcomputed results every few minutes. There will always be plenty ofthings to compute in the detailed affairs of millions of people doingcomplicated things. 4 The repetitive processes of thought are not confined, however, tomatters of arithmetic and statistics. In fact, every time onecombines and records facts in accordance with established logicalprocesses, the creative aspect of thinking is concerned only with theselection of the data and the process to be employed, and themanipulation thereafter is repetitive in nature and hence a fit matterto be relegated to the machines. Not so much has been done alongthese lines, beyond the bounds of arithmetic, as might be done,primarily because of the economics of the situation. The needs ofbusiness, and the extensive market obviously waiting, assured theadvent of mass-produced arithmetical machines just as soon asproduction methods were sufficiently advanced. With machines for advanced analysis no such situation existed; forthere was and is no extensive market; the users of advanced methods ofmanipulating data are a very small part of the population. There are,however, machines for solving differential equations - and functionaland integral equations, for that matter. There are many specialmachines, such as the harmonic synthesizer which predicts the tides.There will be many more, appearing certainly first in the hands of thescientist and in small numbers. If scientific reasoning were limited to the logical processes ofarithmetic, we should not get far in our understanding of the physicalworld. One might as well attempt to grasp the game of poker entirelyby the use of the mathematics of probability. The abacus, with itsbeads string on parallel wires, led the Arabs to positional numerationand 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 accountingmachine. It will be an equal step to the arithmetical machine of thefuture. But even this new machine will not take the scientist wherehe needs to go. Relief must be secured from laborious detailedmanipulation of higher mathematics as well, if the users of it are tofree their brains for something more than repetitive detailedtransformations in accordance with established rules. A mathematicianis not a man who can readily manipulate figures; often he cannot. Heis not even a man who can readily perform the transformation ofequations by the use of calculus. He is primarily an individual whois skilled in the use of symbolic logic on a high plane, andespecially he is a man of intuitive judgment in the choice of themanipulative processes he employs. All else he should be able to turn over to his mechanism, just asconfidently as he turns over the propelling of his car to theintricate mechanism under the hood. Only then will mathematics bepractically effective in bringing the growing knowledge of atomisticsto the useful solution of the advanced problems of chemistry,metallurgy, and biology. For this reason there will come moremachines to handle advanced mathematics for the scientist. Some ofthem will be sufficiently bizarre to suit the most fastidiousconnoisseur of the present artifacts of civilization. 5 The scientist, however, is not the only person who manipulates dataand examines the world about him by the use of logical processes,although he sometimes preserves this appearance by adopting into thefold anyone who becomes logical, much in the manner in which a Britishlabor leader is elevated to knighthood. Whenever logical processes ofthought are employed - that is, whenever thought for a time runs alongan accepted groove - there is an opportunity for the machine. Formallogic used to be a keen instrument in the hands of the teacher in histrying of students' souls. It is readily possible to construct amachine which will manipulate premises in accordance with formallogic, simply by the clever use of relay circuits. Put a set ofpremises into such a device and turn the crank, and it will readilypass out conclusion after conclusion, all in accordance with logicallaw, and with no more slips than would be expected of a keyboardadding machine. Logic can become enormously difficult, and it would undoubtedly bewell to produce more assurance in its use. The machines for higheranalysis have usually been equation solvers. Ideas are beginning toappear for equation transformers, which will rearrange therelationship expressed by an equation in accordance with strict andrather advanced logic. Progress is inhibited by the exceedingly crudeway in which mathematicians express their relationships. They employa symbolism which grew like Topsy and has little consistency; astrange fact in that most logical field. A new symbolism, probably positional, must apparently precede thereduction of mathematical transformations to machine processes. Then,on beyond the strict logic of the mathematician, lies the applicationof logic in everyday affairs. We may some day click off arguments ona machine with the same assurance that we now enter sales on a cashregister. But the machine of logic will not look like a cashregister, even a streamlined model. So much for the manipulation of ideas and their insertion into therecord. Thus far we seem to be worse off than before - for we canenormously extend the record; yet even in its present bulk we canhardly consult it. This is a much larger matter than merely theextraction of data for the purposes of scientific research; itinvolves the entire process by which man profits by his inheritance ofacquired knowledge. The prime action of use is selection, and here weare halting indeed. There may be millions of fine thoughts, and theaccount of the experience on which they are based, all encased withinstone walls of acceptable architectural form; but if the scholar canget at only one a week by diligent search, his syntheses are notlikely to keep up with the current scene. Selection, in this broad sense, is a stone adze in the hands of acabinetmaker. Yet, in a narrow sense and in other areas, somethinghas already been done mechanically on selection. The personnelofficer of a factory drops a stack of a few thousand employee cardsinto a selecting machine, sets a code in accordance with anestablished convention, and produces in a short time a list of allemployees who live in Trenton and know Spanish. Even such devices aremuch too slow when it comes, for example, to matching a set offingerprints with one of five millions on file. Selection devices ofthis sort will soon be speeded up from their present rate of reviewingdata at a few hundred a minute. By the use of photocells andmicrofilm 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 examiningin turn every one of a large set of items, and by picking out thosewhich have certain specified characteristics. There is another formof selection best illustrated by the automatic telephone exchange.You dial a number and the machine selects and connects just one of amillion possible stations. It does not run over them all. It paysattention only to a class given by a first digit, and so on; and thusproceeds rapidly and almost unerringly to the selected station. Itrequires a few seconds to make the selection, although the processcould be speeded up if increased speed were economically warranted.If necessary, it could be made extremely fast by substitutingthermionic-tube switching for mechanical switching, so that the fullselection could be made in one-hundredth of a second. No one wouldwish to spend the money necessary to make this change in the telephonesystem, but the general idea is applicable elsewhere. Take the prosaic problem of the great department store. Every time acharge sale is made, there are a number of things to be done.. Theinventory needs to be revised, the salesman needs to be given creditfor the sale, the general accounts need an entry, and, most important,the customer needs to be charged. A central records device has beendeveloped in which much of this work is done conveniently. Thesalesman places on a stand the customer's identification card, his owncard, and the card taken from the article sold - all punched cards.When he pulls a lever, contacts are made through the holes, machineryat a central point makes the necessary computations and entries, andthe proper receipt is printed for the salesman to pass to thecustomer. But there may be ten thousand charge customers doing business with thestore, and before the full operation can be completed someone has toselect the right card and insert it at the central office. Now rapidselection can slide just the proper card into position in an instantor two, and return it afterward. Another difficulty occurs, however.Someone must read a total on the card, so that the machine can add itscomputed item to it. Conceivably the cards might be of the dryphotography type I have described. Existing totals could then be readby photocell, and the new total entered by an electron beam. The cards may be in miniature, so that they occupy little space. Theymust move quickly. They need not be transferred far, but merely intoposition so that the photocell and recorder can operate on them.Positional dots can enter the data. At the end of the month a machinecan readily be made to read these and to print an ordinary bill. Withtube selection, in which no mechanical parts are involved in theswitches, little time need be occupied in bringing the correct cardinto use - a second should suffice for the entire operation. Thewhole record on the card may be made by magnetic dots on a steel sheetif desired, instead of dots to be observed optically, following thescheme by which Poulsen long ago put speech on a magnetic wire. Thismethod has the advantage of simplicity and ease of erasure. By usingphotography, however, one can arrange to project the record inenlarged form, and at a distance by using the process common intelevision equipment. One can consider rapid selection of this form, and distant projectionfor other purposes. To be able to key one sheet of a million beforean operator in a second or two, with the possibility of then addingnotes thereto, is suggestive in many ways. It might even be of use inlibraries, but that is another story. At any rate, there are now someinteresting combinations possible. One might, for example, speak to amicrophone, in the manner described in connection with thespeech-controlled typewriter, and thus make his selections. It wouldcertainly beat the usual file clerk. 6 The real heart of the matter of selection, however, goes deeper than alag in the adoption of mechanisms by libraries, or a lack ofdevelopment of devices for their use. Our ineptitude in getting atthe record is largely caused by the artificiality of systems ofindexing. When data of any sort are placed in storage, they are filedalphabetically or numerically, and information is found (when it is)by tracing it down from subclass to subclass. It can be in only oneplace, unless duplicates are used; one has to have rules as to whichpath will locate it, and the rules are cumbersome. Having found oneitem, moreover, one has to emerge from the system and re-enter on anew 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 issuggested by the association of thoughts, in accordance with someintricate web of trails carried by the cells of the brain. It hasother characteristics, of course; trails that are not frequentlyfollowed are prone to fade, items are not fully permanent, memory istransitory. Yet the speed of action, the intricacy of trails, thedetail 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 hemay even improve, for his records have relative permanency. The firstidea, however, to be drawn from the analogy concerns selection.Selection by association, rather than by indexing, may yet bemechanized. One cannot hope thus to equal the speed and flexibilitywith which the mind follows an associative trail, but it should bepossible to beat the mind decisively in regard to the permanence andclarity of the items resurrected from storage. Consider a future device for individual use, which is a sort ofmechanized private file and library. It needs a name, and to coinone at random, ``memex'' will do. A memex is a device in which anindividual stores all his books, records, and communications, andwhich is mechanized so that it may be consulted with exceeding speedand flexibility. It is an enlarged intimate supplement to his memory. It consists of a desk, and while it can presumably be operated from adistance, it is primarily the piece of furniture at which he works.On the top are slanting translucent screens, on which material can beprojected for convenient reading. There is a keyboard, and sets ofbuttons and levers. Otherwise it looks like an ordinary desk. In one end is the stored material. The matter of bulk is well takencare of by improved microfilm. Only a small part of the interior ofthe memex is devoted to storage, the rest to mechanism. Yet if theuser inserted 5000 pages of material a day it would take him hundredsof years to fill the repository, so he can be profligate and entermaterial freely. Most of the memex contents are purchased on microfilm ready forinsertion. Books of all sorts, pictures, current periodicals,newspapers, are thus obtained and dropped into place. Businesscorrespondence takes the same path. And there is provision for directentry. On the top of the memex is a transparent platen. On this areplaced longhand notes, photographs, memoranda, all sort of things.When one is in place, the depression of a lever causes it to bephotographed 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 theusual scheme of indexing. If the user wishes to consult a certainbook, he taps its code on the keyboard, and the title page of the bookpromptly appears before him, projected onto one of his viewingpositions. Frequently-used codes are mnemonic, so that he seldomconsults his code book; but when he does, a single tap of a keyprojects it for his use. Moreover, he has supplemental levers. Ondeflecting one of these levers to the right he runs through the bookbefore him, each page in turn being projected at a speed which justallows a recognizing glance at each. If he deflects it further to theright, he steps through the book 10 pages at a time; still further at100 pages at a time. Deflection to the left gives him the samecontrol backwards. A special button transfers him immediately to the first page of theindex. Any given book of his library can thus be called up andconsulted with far greater facility than if it were taken from ashelf. As he has several projection positions, he can leave one itemin position while he calls up another. He can add marginal notes andcomments, taking advantage of one possible type of dry photography,and it could even be arranged so that he can do this by a stylusscheme, such as is now employed in the telautograph seen in railroadwaiting rooms, just as though he had the physical page before him. 7 All this is conventional, except for the projection forward ofpresent-day mechanisms and gadgetry. It affords an immediate step,however, to associative indexing, the basic idea of which is aprovision whereby any item may be caused at will to select immediatelyand automatically another. This is the essential feature of thememex. The process of tying two items together is the importantthing. When the user is building a trail, he names it, inserts the name inhis code book, and taps it out on his keyboard. Before him are thetwo items to be joined, projected onto adjacent viewing positions. Atthe bottom of each there are a number of blank code spaces, and apointer is set to indicate one of these on each item. The user taps asingle key, and the items are permanently joined. In each code spaceappears the code word. Out of view, but also in the code space, isinserted a set of dots for photocell viewing; and on each item thesedots by their positions designate the index number of the other item. Thereafter, at any time, when one of these items is in view, the othercan be instantly recalled merely by tapping a button below thecorresponding code space. Moreover, when numerous items have beenthus joined together to form a trail, they can be reviewed in turn,rapidly or slowly, by deflecting a lever like that used for turningthe pages of a book. It is exactly as though the physical items hadbeen gathered together to form a new book. It is more than this, forany item can be joined into numerous trails. The owner of the memex, let us say, is interested in the origin andproperties of the bow and arrow. Specifically he is studying why theshort Turkish bow was apparently superior to the English long bow inthe skirmishes of the Crusades. He has dozens of possibly pertinentbooks and articles in his memex. First he runs through anencyclopedia, finds an interesting but sketchy article, leaves itprojected. Next, in a history, he finds another pertinent item, andties the two together. Thus he goes, building a trail of many items.Occasionally he inserts a comment of his own, either linking it intothe main trail or joining it by a side trail to a particular item.When it becomes evident that the elastic properties of availablematerials had a great deal to do with the bow, he branches off on aside trail which takes him through textbooks on elasticity and tablesof physical constants. He inserts a page of longhand analysis of hisown. Thus he builds a trail of his interest through the maze ofmaterials available to him. And his trails do not fade. Several years later, his talk with afriend turns to the queer ways in which a people resist innovations,even of vital interest. He has an example, in the fact that theoutranged Europeans still failed to adopt the Turkish bow. In fact hehas a trail on it. A touch brings up the code book. Tapping a fewkeys projects the head of the trail. A lever runs through it at will,stopping at interesting items, going off on side excursions. It is aninteresting trail, pertinent to the discussion. So he sets areproducer in action, photographs the whole trail out, and passes itto his friend for insertion in his own memex, there to be linked intothe more general trail. 8 Wholly new forms of encyclopedias will appear, ready-made with a meshof associative trails running through them, ready to be dropped intothe memex and there amplified. The lawyer has at his touch theassociated opinions and decisions of his whole experience, and of theexperience of friends and authorities. The patent attorney has oncall the millions of issued patents, with familiar trails to everypoint of his client's interest. The physician, puzzled by itspatient's reactions, strikes the trail established in studying anearlier similar case, and runs rapidly through analogous casehistories, with side references to the classics for the pertinentanatomy and histology. The chemist, struggling with the synthesis ofan organic compound, has all the chemical literature before him in hislaboratory, with trails following the analogies of compounds, and sidetrails 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 overcivilization at a particular epoch. There is a new profession oftrail blazers, those who find delight in the task of establishinguseful trails through the enormous mass of the common record. Theinheritance from the master becomes, not only his additions to theworld's record, but for his disciples the entire scaffolding by whichthey were erected. Thus science may implement the ways in which man produces, stores, andconsults the record of the race. It might be striking to outline theinstrumentalities of the future more spectacularly, rather than tostick closely to the methods and elements now known and undergoingrapid development, as has been done here. Technical difficulties ofall sorts have been ignored, certainly, but also ignored are means asyet unknown which may come any day to accelerate technical progress asviolently as did the advent of the thermionic tube. In order that thepicture may not be too commonplace, by reason of sticking topresent-day patterns, it may be well to mention one such possibility,not to prophesy but merely to suggest, for prophecy based on extensionof the known has substance, while prophecy founded on the unknown isonly a doubly involved guess. All our steps in creating or absorbing material of the record proceedthrough one of the senses - the tactile when we touch keys, the oralwhen we speak or listen, the visual when we read. Is it not possiblethat some day the path may be established more directly? We know that when the eye sees, all the consequent information istransmitted to the brain by means of electrical vibrations in thechannel of the optic nerve. This is an exact analogy with theelectrical vibrations which occur in the cable of a television set:they convey the picture from the photocells which see it to the radiotransmitter from which it is broadcast. We know further that if wecan approach that cable with the proper instruments, we do not need totouch it; we can pick up those vibrations by electrical induction andthus discover and reproduce the scene which is being transmitted, justas a telephone wire may be tapped for its message. The impulses which flow in the arm nerves of a typist convey to herfingers the translated information which reaches her eye or ear, inorder that the fingers may be caused to strike the proper keys. Mightnot these currents be intercepted, either in the original form inwhich information is conveyed to the brain, or in the marvelouslymetamorphosed form in which they then proceed to the hand? By bone conduction we already introduce sounds into the nerve channelsof the deaf in order that they may hear. Is it not possible that wemay learn to introduce them without the present cumbersomeness offirst transforming electrical vibrations to mechanical ones, which thehuman mechanism promptly transforms back to the electrical form? Witha couple of electrodes on the skull the encephalograph now producespen-and-ink traces which bear some relation to the electricalphenomena going on in the brain itself. True, the record isunintelligible, except as it points out certain gross misfunctioningof the cerebral mechanism; but who would now place bounds on wheresuch a thing may lead? In the outside world, all forms of intelligence, whether of sound orsight, have been reduced to the form of varying currents in anelectric circuit in order that they may be transmitted. Inside thehuman frame exactly the same sort of process occurs. Must we alwaystransform to mechanical movements in order to proceed from oneelectrical phenomenon to another? It is a suggestive thought, but ithardly warrants prediction without losing touch with reality andimmediateness. Presumably man's spirit should be elevated if he can better review hisshady past and analyze more completely and objectively his presentproblems. He has built a civilization so complex that he needs tomechanize his record more fully if he is to push his experiment to itslogical conclusion and not merely become bogged down part way there byovertaxing his limited memory. His excursion may be more enjoyable ifhe can reacquire the privilege of forgetting the manifold things hedoes not need to have immediately at hand, with some assurance that hecan find them again if they prove important. The applications of science have built man a well-supplied house, andare teaching him to live healthily therein. They have enabled him tothrow masses of people against another with cruel weapons. They mayyet allow him truly to encompass the great record and to grow in thewisdom of race experience. He may perish in conflict before he learnsto wield that record for his true good. Yet, in the application ofscience to the needs and desires of man, it would seem to be asingularly unfortunate stage at which to terminate the process, or tolose hope as to the outcome.
