H.W.: In July, 1945, the US magazine 'The Atlantic Monthly' published an essay by Vannevar Bush, head of one of the US governement's think tanks. In retrospect, the piece was almost visionary. It pre-empts some of the main developments in computing and is meanwhile considered one of the key texts in the history of computer theory. Moreover, it focuses attention on problems for which computers possibly provide the answers. This is the first time the essay has been printed in German; for reasons of space we have, however, had to cut it by about two thirds.
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 the 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 Emersons' 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 of 'The Atlantic Monthly' -
This has not been an 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? [...] 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. [...]
H.W.: In the four subsequent sections, which we cannot reprint here, Bush summarizes the recording technology available in his day: the development of calculators since Leibniz and Babbage, microphotography as a way of compressing large amounts, Facsimile transmission, TV, the first attempts at mechanical speech synthesis and voice recognition, Hollorith punch-card machines and electron valves. He speculates that it may be necessary to develop a universal language - 'a new symbolism, probably positional' - and distinguishes within intellectual thought between 'creative' and 'repetitive thought'. He believes mechanical assistance is only of use for repetitive activities. And he frequenthy returns to the problem of identifying and absorbing in the first place those items of information that are of relevance for one's own work: "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."
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 concern 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 o furniture at which be 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 take the same
path. And there is provision for direct entry. On the top of the memex
is a transparent plate. On this are placed long hand notes, photographs,
memoranda, all sorts 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 defecting 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. Deflection
to the left gives him the same control backwards.
A special button transfers him immediatly 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 been in railroad waiting rooms, just as though he had the
physical page before him.
7
All this is conventional, except for the projection forward of present-day
mechanisms and gadgetry. If affords an immediat step, however, to associative
indexing, the basic idea of which is a provision whereby any item may be
caused at will to select immediatly 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 positons 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 use for turning the pages of a book. It is exactly as
though the physical items had been gathered together from widely separated
sources and bound 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 an 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 be builds
a trail of his interst 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 out-ranged 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.
8
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 a 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 labratory,
with trails following the analogies of compounds, and side trails to their
physical an chemical behavior.
The historian, with a vast chronological account of a people, parallels
it with a skip trail which stops only on 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 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 therminonic tube, In order that the picture my not be too commonplace,
by reason of sticking to present-day patterns, it may be well to mention
one such posibility, 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 proper instruments, we
do not need to touch it, can pick up those vibrations by electrical induction
thus discover and reproduce the scene which is be transmitted, just as
a telephone wire may be tapped its message.
By bone conduction we already introduce sound into the nerve channels
of the deaf in order that .... may hear. Is it not possible that we may
learn to introduce them without the present cumbersomeness first transforming
electrical vibrations to mechanic ones, which the human mechansim 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 the brain itself. True,
the record is unintelligible, except as it point 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 fram 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 per diction without
losing touch with reality and immediateness.
Presumably man's spirit should be elevated if it 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 records more fully if he is to push his experiment to its logical conclusion
and not merely become bogged down part way there by overtaxim his limited
memory. His excursions may be more enjoyable if he can reacquire the privilege
of forgetting the mainifold things he does not need to have immediately
at hand, with some assurance that he can firm 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 one 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 singularly unfortunate stage at which
to terminate the process, or to lose hope as to the outcome.
H.W.: A postscript is in order here: Only recently have we learned
to regard the computer not as a thinking machine but as a medium. And in
this regard, Bush is truly astonishing. For his essay essentially starts
from the assumption that a communication problem exists. The individual
scientist, so the initial proposition, has an ever harder time using the
results of his colleagues' studies in his own work; the amount of relevant
material increases exponentially, and the proportion of it he reads becomes
ever smaller. As a consequence, there is a crisis in his exchange of information
with others, above all within the pool of knowledge per se.
A classical communications problem. And Bush_s answer is to develop
a machine that at first is only intended for the individual_s desk-top.
The memex makes work faster, simpler and more efficient, and Bush even
expressly foresees the transfer of materials. But would now one really
have been confident that the scientist would be able to keep pace with
the growth in available material? I contend that the memex, while supporting
scientific interchange with individual colleagues, more or less leaves
the core problem, namely communication with the pool of knowledge, untouched.
The initial problem of 'inundation with information' and the technological
answer to it, the memex, do not match up.
And it is all the more astonishing that the development of computers
has gone in exactly the same direction once again. After having for many
years given us stand-alone machines (first of all main frames and then
desk-top computers) now, with networking, access to outside data is possible.
Access - 'our ineptitude in getting at the record' - also appears to have
been regulated to a certain extent. The real problem, however, Bush says,
stems from the amount of data itself. And it would not seem possible to
solve this by mechanical selection and associative mnemonic storage.