Strong AI definitely has the capability of being on the level of humans and surpassing them as well. The thing people doubt is whether we will ever be able to create a truly strong AI, @federicopiston also referred to this in his chapter regarding robots replacing humans in the work place, he referenced the Chinese Room Argument, which is often used to refute the notion that strong AI will one day become a reality. Personally, I think it's definitely possible, people used to come up with arguments against why humans could never be able to fly but we got around that with the airplane. Our imaginations are infinite, and I do truly believe that we have the capacity to build things that could take us out of this world (literally and figuratively).
Thanks for the insightful comment!
~ Np