The acceleration of technological progress has been the central
         feature of this century. I argue in this paper that we are on the edge
         of change comparable to the rise of human life on Earth. The precise
         cause of this change is the imminent creation by technology of
         entities with greater than human intelligence. There are several means
         by which science may achieve this breakthrough (and this is another
         reason for having confidence that the event will occur):
            o The development of computers that are "awake" and
              superhumanly intelligent. (To date, most controversy in the
              area of AI relates to whether we can create human equivalence
              in a machine. But if the answer is "yes, we can", then there
              is little doubt that beings more intelligent can be constructed
              shortly thereafter.
            o Large computer networks (and their associated users) may "wake
              up" as a superhumanly intelligent entity.
            o Computer/human interfaces may become so intimate that users
              may reasonably be considered superhumanly intelligent.
            o Biological science may find ways to improve upon the natural
              human intellect.

              The first three possibilities depend in large part on 
         improvements in computer hardware. Progress in computer hardware has
         followed an amazingly steady curve in the last few decades [16]. Based
         largely on this trend, I believe that the creation of greater than
         human intelligence will occur during the next thirty years.  (Charles
         Platt [19] has pointed out the AI enthusiasts have been making claims
         like this for the last thirty years. Just so I'm not guilty of a
         relative-time ambiguity, let me more specific: I'll be surprised if
         this event occurs before 2005 or after 2030.)

              What are the consequences of this event? When greater-than-human
         intelligence drives progress, that progress will be much more rapid.
         In fact, there seems no reason why progress itself would not involve
         the creation of still more intelligent entities -- on a still-shorter
         time scale. The best analogy that I see is with the evolutionary past:
         Animals can adapt to problems and make inventions, but often no faster
         than natural selection can do its work -- the world acts as its own
         simulator in the case of natural selection. We humans have the ability
         to internalize the world and conduct "what if's" in our heads; we can
         solve many problems thousands of times faster than natural selection.
         Now, by creating the means to execute those simulations at much higher
         speeds, we are entering a regime as radically different from our human
         past as we humans are from the lower animals.

              From the human point of view this change will be a throwing away
         of all the previous rules, perhaps in the blink of an eye, an
         exponential runaway beyond any hope of control. Developments that
         before were thought might only happen in "a million years" (if ever)
         will likely happen in the next century. (In [4], Greg Bear paints a
         picture of the major changes happening in a matter of hours.)

              I think it's fair to call this event a singularity ("the
         Singularity" for the purposes of this paper). It is a point where our
         models must be discarded and a new reality rules. As we move closer
         and closer to this point, it will loom vaster and vaster over human
         affairs till the notion becomes a commonplace. Yet when it finally
         happens it may still be a great surprise and a greater unknown.  In
         the 1950s there were very few who saw it: Stan Ulam [27] paraphrased
         John von Neumann as saying:

              One conversation centered on the ever accelerating progress of
              technology and changes in the mode of human life, which gives the
              appearance of approaching some essential singularity in the
              history of the race beyond which human affairs, as we know them,
              could not continue.

              Von Neumann even uses the term singularity, though it appears he
         is still thinking of normal progress, not the creation of superhuman
         intellect. (For me, the superhumanity is the essence of the
         Singularity. Without that we would get a glut of technical riches,
         never properly absorbed (see [24]).)

              In the 1960s there was recognition of some of the implications of
         superhuman intelligence. I. J. Good wrote [10]:

              Let an ultraintelligent machine be defined as a machine
              that can far surpass all the intellectual activities of any
              any man however clever.  Since the design of machines is one of
              these intellectual activities, an ultraintelligent machine could
              design even better machines; there would then unquestionably
              be an "intelligence explosion," and the intelligence of man
              would be left far behind.  Thus the first ultraintelligent
              machine is the _last_ invention that man need ever make, 
              provided that the machine is docile enough to tell us how to
              keep it under control.
              ...
              It is more probable than not that, within the twentieth century,
              an ultraintelligent machine will be built and that it will be
              the last invention that man need make.

              Good has captured the essence of the runaway, but does not pursue
         its most disturbing consequences. Any intelligent machine of the sort
         he describes would not be humankind's "tool" -- any more than humans
         are the tools of rabbits or robins or chimpanzees. 

              Through the '60s and '70s and '80s, recognition of the cataclysm
         spread [28] [1] [30] [4]. Perhaps it was the science-fiction writers
         who felt the first concrete impact.  After all, the "hard"
         science-fiction writers are the ones who try to write specific stories
         about all that technology may do for us.  More and more, these writers
         felt an opaque wall across the future. Once, they could put such
         fantasies millions of years in the future [23].  Now they saw that
         their most diligent extrapolations resulted in the unknowable ...
         soon. Once, galactic empires might have seemed a Post-Human domain.
         Now, sadly, even interplanetary ones are.

              What about the '90s and the '00s and the '10s, as we slide toward
         the edge? How will the approach of the Singularity spread across the
         human world view? For a while yet, the general critics of machine
         sapience will have good press. After all, till we have hardware as
         powerful as a human brain it is probably foolish to think we'll be
         able to create human equivalent (or greater) intelligence. (There is
         the far-fetched possibility that we could make a human equivalent out
         of less powerful hardware, if were willing to give up speed, if we
         were willing to settle for an artificial being who was literally slow
         [29]. But it's much more likely that devising the software will be a
         tricky process, involving lots of false starts and experimentation. If
         so, then the arrival of self-aware machines will not happen till after
         the development of hardware that is substantially more powerful than
         humans' natural equipment.)

              But as time passes, we should see more symptoms. The dilemma felt
         by science fiction writers will be perceived in other creative
         endeavors.  (I have heard thoughtful comic book writers worry about
         how to have spectacular effects when everything visible can be
         produced by the technically commonplace.) We will see automation
         replacing higher and higher level jobs. We have tools right now
         (symbolic math programs, cad/cam) that release us from most low-level
         drudgery. Or put another way: The work that is truly productive is the
         domain of a steadily smaller and more elite fraction of humanity. In
         the coming of the Singularity, we are seeing the predictions of _true_
         technological unemployment finally come true.

              Another symptom of progress toward the Singularity: ideas
         themselves should spread ever faster, and even the most radical will
         quickly become commonplace.  When I began writing, it seemed very easy
         to come up with ideas that took decades to percolate into the cultural
         consciousness; now the lead time seems more like eighteen months. (Of
         course, this could just be me losing my imagination as I get old, but
         I see the effect in others too.) Like the shock in a compressible
         flow, the Singularity moves closer as we accelerate through the
         critical speed.

              And what of the arrival of the Singularity itself? What can be 
         said of its actual appearance? Since it involves an intellectual
         runaway, it will probably occur faster than any technical revolution
         seen so far.  The precipitating event will likely be unexpected --
         perhaps even to the researchers involved. ("But all our previous
         models were catatonic! We were just tweaking some parameters....") If
         networking is widespread enough (into ubiquitous embedded systems), it
         may seem as if our artifacts as a whole had suddenly wakened.

              And what happens a month or two (or a day or two) after that? I 
         have only analogies to point to: The rise of humankind. We will be in
         the Post-Human era. And for all my rampant technological optimism,
         sometimes I think I'd be more comfortable if I were regarding these
         transcendental events from one thousand years remove ... instead of
         twenty.