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as we may think 中英文

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2021-01-22 18:54
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写景片段-电脑桌面图标有蓝色阴影怎么去掉

2021年1月22日发(作者:姜泗长)
by
Vannevar Bush


As We May Think
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
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 not 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
American Scholar,
man and the sum of our knowledge.

THE EDITOR

T
his 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 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, 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.
1

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 is
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 thousands 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 hundreds 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.
2

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 exposures, 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
two 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 in 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 would predict that such a process will always remain clumsy,
slow, and faulty in detail. Television equipment today transmits sixteen reasonably good
pictures 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 only 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 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 at 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.
3

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 is 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 chords entered into 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 a 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 in 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 whole roomful of
girls armed with simple key board 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.
4

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 machine. 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 strung 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 transformations 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 still 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.
5

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 of the
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 million 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 a thousand 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, then only to a subclass of this given by the second 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 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.
6

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 records have
relative permanency. The first idea, however, to be drawn from the analogy concerns
selection. Selection by association, rather than 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,
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

写景片段-电脑桌面图标有蓝色阴影怎么去掉


写景片段-电脑桌面图标有蓝色阴影怎么去掉


写景片段-电脑桌面图标有蓝色阴影怎么去掉


写景片段-电脑桌面图标有蓝色阴影怎么去掉


写景片段-电脑桌面图标有蓝色阴影怎么去掉


写景片段-电脑桌面图标有蓝色阴影怎么去掉


写景片段-电脑桌面图标有蓝色阴影怎么去掉


写景片段-电脑桌面图标有蓝色阴影怎么去掉



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