As it happens, in the last five years or so arguments about computer sentience have started to subside. The idea is assumed to be true by most of my colleagues; for them, the argument is over. It is not over for me.
I must report that back when the arguments were still white hot, it was the oddest feeling to debate someone like Cybernetic Totalist philosopher Daniel Dennett. He would state that humans were simply specialized computers, and that imposing some fundamental ontological distinction between humans and computers was a sentimental waste of time.
"But don't you experience your life? Isn't experience something apart from what you could measure in a computer?", I would say. My debating opponent would typically say something like "Experience is just an illusion created because there is one part of a machine (you) that needs to create a model of the function of the rest of the machine- that part is your experiential center."
I would retort that experience is the only thing that isn't reduced by illusion. That even illusion is itself experience. A correlate, alas, is that experience is the very thing that can only be experienced. This lead me into the odd position of publicly wondering if some of my opponents simply lacked internal experience. (I once suggested that among all humanity, one could only definitively prove a lack of internal experience in certain professional philosophers.)
In truth, I think my perennial antagonists do have internal experience but choose not to admit it in public for a variety of reasons, most often because they enjoy annoying others.
Another motivation might be the "Campus Imperialism" I invoked earlier. Representatives of each academic discipline occasionally assert that they possess a most privileged viewpoint that somehow contains or subsumes the viewpoints of their rivals. Physicists were the alpha-academics for much of the twentieth century, though in recent decades "postmodern" humanities thinkers managed to stage something of a comeback, at least in their own minds. But technologists are the inevitable winners of this game, as they change the very components of our lives out from under us. It is tempting to many of them, apparently, to leverage this power to suggest that they also possess an ultimate understanding of reality, which is something quite apart from having tremendous influence on it.
Another avenue of explanation might be neo-Freudian, considering that the primary inventor of the idea of machine sentience, Alan Turing, was such a tortured soul. Turing died in an apparent suicide brought on by his having developed breasts as a result of enduring a hormonal regimen intended to reverse his homosexuality. It was during this tragic final period of his life that he argued passionately for machine sentience, and I have wondered whether he was engaging in a highly original new form of psychological escape and denial; running away from sexuality and mortality by becoming a computer.
At any rate, what is peculiar and revealing is that my cybernetic totalist friends confuse the viability of a perspective with its triumphant superiority. It is perfectly true that one can think of a person as a gene's way of propagating itself, as per Dawkins, or as a sexual organ used by machines to make more machines, as per McLuhan (as quoted in the masthead of every issue of Wired Magazine), and indeed it can even be beautiful to think from these perspectives from time to time. As the anthropologist Steve Barnett pointed out, however, it would be just as reasonable to assert that "A person is shit's way of making more shit."