It doesn't have a presence in reality, it apparently won't have a presence in reality any time soon, but saying it can't happen is about as egotistical as we could be. Our generation has not yet discovered a means to synthesize this type of intelligence, but there is still plenty of time left to figure it out. We just don't know yet if it can happen or not.
The credibility of the claims is somewhat diminished by the convenience. His argument is literally "I am going to be able to live just long enough to live forever and resurrect my dead father."
And assuming we did invent strong AI, so what? It doesn't necessarily or immediately lead to a singularity. We already have several billion human brains and have had them for quite some time.
You can rewrite your neurons too. It's called learning.
Here's a thought experiment though, more in the direction you meant. Imagine you had a tool that let you rewire your own neurons however you wanted. Again, so what? There are something like 100 trillion synapses in an adult brain. What are the chances that you'll use this tool to actually improve your own intelligence (when evolution has been playing that game for millions of years) vs just giving yourself a lobotomy?
Now, how is it any different in the hands of an artificial intelligence that is no more intelligent than us?
All of this futurism just seems like bad assumptions stacked on top of more bad assumptions. I still think Pinker said it best:
"There is not the slightest reason to believe in a coming singularity. The fact that you can visualize a future in your imagination is not evidence that it is likely or even possible. Look at domed cities, jet-pack commuting, underwater cities, mile-high buildings, and nuclear-powered automobiles—all staples of futuristic fantasies when I was a child that have never arrived. Sheer processing power is not a pixie dust that magically solves all your problems."
That seems like a pretty terrible analogy. All of those examples are possible today, but their cost doesn't justify their utility, and nobody pursues them. On the other hand, it's fairly easy to think of practical uses for artificial intelligence, and research in this area is actively pursued by researchers around the world.
Like I said, it would take someone incredibly egotistical (apparently such as a Harvard psychology professor) to suggest artificial intelligence isn't possible based on where we are right now, where we were 30 years ago, or where it appears we're headed over the next 30 years. Based on this quote, Pinker's conception of the world doesn't appear to extend beyond the span of his own lifetime.
"The fact that you can visualize a future in your imagination is not evidence that it is likely or even possible."
Nor is the fact that some of his childhood fantasies didn't come to fruition evidence that it's impossible or even unlikely. What's his point? One bad argument doesn't right another.
There is a difference between a strong AI position and the statement that such an intelligence would be qualitatively different than currently operating, natural intelligence, and a further one between that and the statement that such an intelligence would be quantitatively better (whatever that means), which is the "singularity" as far as I can tell.
Only fools speak in absolute terms about unknowns.
That is a tautology (because the inverse is a paradox: If you prove something has travelled faster than light, that would invalidate the current definition of "faster.")
But! I think the singularity deserves to have a presence in fiction, even if it can't have one in reality. Some of the best sci-fi is built on whimsical and unrealistic technologies.