> However, I strongly suspect that it's theoretically possible to build a machine that "thinks" as well as a human

Not any time soon. Modern "AI" research built on completely wrong assumptions about how neurons work from the middle of XX century. It turned out they are much more complex than that (long story short every single neuron is analogous to the "neural network" as AI researchers understand them). See more at https://www.youtube.com/watch?v=hmtQPrH-gC4