First of all, what is this thing called a Singularity? I think of it in two ways. First: Narrowly, as a tremendously rapid increase of the rate of technological progress (a "tech Singularity"). Second: More broadly, as the creation of intelligences that are so far beyond us that we can not understand most of what they're up to (a "subjective Singularity").
A "tech Singularity" is a projected brief interval of time in which the practical innovation rate becomes so fast as to seem essentially instantaneous to humans. For example, consider innovations such as the personal computer, the fax machine, the automobile, the gene chip, object-oriented programming, quark theory, abstract algebra, et cetera. Once a few hundred innovations of this magnitude occur each day, we will have definitely moved into the Singularity. Basically, a tech Singularity is a near-mathematical-singularity in the rate of technological advance.
In a broader sense, I think of a "subjective Singularity" as involving either:
Drastic alteration in human subjective experience. Technologies like virtual reality, genetic engineering, neuromodification, and uploading have the potential to drastically change the experience of being human. Once these technologies have transformed the subjective experience of a moderately large percentage of humans, in a highly significant way, then we will have reached a "subjective Singularity": a replacement of human mind with something different.
The creation of nonhuman intelligences that are tremendously smarter than us, and most of whose activities are as opaque to us as our activities are to a dog.
In principle, either variety of subjective Singularity could occur without a tech Singularity; but I think the two are likely to come together.... It is the combination that I refer to generically as "The Singularity."
As for what life or mind will be like after the Singularity, I think this is something we can not know. The most important aspects of post-Singularity reality and mind will likely be as opaque to an unimproved human as advanced mathematics is to a dog.
The advent of the Singularity is not certain, but given the exponential trends observable in technological and scientific progress, it seems very likely. The Singularity will probably be brought about by the convergence of a large number of interrelated technologies, a process that Kurzweil has described very well.
It seems likely that in the late pre-Singularity years, Artificial General Intelligence programs will play a starring role in bringing the Singularity about - because once such programs are able to invent things at the human level, they will probably be able to modify their design, enabling them to supersede human powers of invention. They will thus be able to push toward the Singularity faster than humans can.
How likely any of our present actions are to significantly affect the Singularity is difficult to say. On the one hand, huge processes like this tend to take their course independently of the actions of any one being. On the other hand, the Singularity may be a multifurcation point, so that a small nudge in one direction or another can have a big effect on what path is taken.
What can we do to encourage the Singularity to go well? Unfortunately,
all we have to guide us is human common sense; there is no science of such
complex processes. We all should ensure that human alterations and artificial
intelligences and other advanced technologies are constructed and deployed
in a morally acceptable way.
Singularity Action Group website frames version.