Another message from Vinge:
I prefer the term singularity for several reasons (and I think all or almost all of these points have been made by other posters):
o Very likely the degree of change is going to be on the order of difference between a chimpanzee (or a goldfish :-) and a human. "Horizon" sounds more like past tech horizons, which could be accomodated by the innate flexibility of the human mind. Very likely, the upcoming change will be qualitatively greater -- though augmented participants might take it in stride.
o The notion of "horizon" has the attendent notion of persistence
of identity. When change is large enough or fast enough, this
is a problem. I see two analogies on this:
+ The change that leads from a zygote (or 4-cell embryo) to a
human child. It might be argued that the early embyro has simply
been enhanced. Certainly the child encompasses the
embryo.... And yet the change is large enough that the horizon
metaphor does not seem appropriate (to me) to describe the
change. (I do see at least one advantage to the horizon
metaphor, however; it implies that change is ongoing.)
+ When I think about labile nature of processes in the
distributed systems that are being designed these days, and then
imagine what it would be like if the such systems could be
scaled up so that some of the processes were of human power or
greater -- then I see weird things being done to the notion of
persistent identity and the underlying notion of self. Again,
this makes it hard for me to see the process as one of "us" just
moving along to better things.