Machines that think? That's as fallacious as people that think! Thinking involves processing information, begetting new physical order from incoming streams of physical order. Thinking is a precious ability, which unfortunately, is not the privilege of single units, such as machines or people, but a property of the systems in which these units come to "life."
Of course I am being provocative here, since at the individual level we do process information. We do think—sometimes—or at least we feel like we do. But "our" ability to think is not entirely "ours," it is borrowed since the hardware and software that we use to think were not begot by us. You and I did not evolve the genes that helped organize our brains or the language we use to structure our thoughts. Our capacity to think is completely dependent on events that happened prior to our mundane existence: the past chapters of biological and cultural evolution. So we can only understand our ability to think, and the ability of machines to mimic thought, by considering how the ability of a unit to process information relates to its context.
Think of a human that was born in the dark solitude of empty space. She would have nothing to think about. The same would be true for an isolated and inputless computing machine. In this context, we can call our borrowed ability to process information "little" thinking—since it is a context dependent ability that happens at the individual level. "Large" thinking, on the other hand, is the ability to process information that is embodied in systems, where units like machines or us, are mere pawns.
Separating the little thinking of humans from the larger thinking of systems (which involves the process that begets the hardware and software that allow units to "little think") helps us understand the role of thinking machines in this larger context. Our ability to think is not only borrowed. It also hinges on the use and abuse of mediated interactions. For human-machine systems to think, humans need to eat and regurgitate each other's mental vomit, which sometimes takes the form of words. But since words vanish in the wind, our species' enormous ability to think hinges on more sophisticated techniques to communicate and preserve the information that we generate: our ability to encode information in matter.
For a hundred thousand years our species has been busy transforming our planet into a giant tape player. The planet earth is the medium where we print our ideas, sometimes in symbolic form, such as text and paintings, but more importantly in objects, like hair driers, vacuum cleaners, buildings, and cars, which are built from the mineral loins of planet earth. Our society has a great collective ability to process information because our communication involves more than words, it involves the creation of objects, which do not transmit something as flimsy as an idea, but something as concrete as the practical uses of knowledge and knowhow. Objects augment us, as they allow us to do things without knowing how. We all get to enjoy the teeth preserving powers of toothpaste without knowing how to synthesize Sodium Fluoride, or the benefits of long distance travel without knowing how to build a plane. By the same token, we all enjoy the benefits of sending texts throughout the world in seconds through social media, or of performing complex mathematical operations by pressing a few keys on a laptop computer.
But our ability to create the trinkets that augment us has also evolved—of course—as a result of our collective willingness to eat each other's mental vomit. This evolution is the one that brings us now to the point in which we have "media" that is beginning to rival our ability to process information, or "little think."
For most of our history our trinkets were static objects. Even our tools were solidified chunks of order, such as stone axes, knives, and knitting needles. A few centuries ago we developed the ability to outsource muscle and motion to machines, causing one of the greatest economic expansions of history. Now, we have evolved our collective capacity to process information by creating objects that are endowed with the ability to beget and recombine physical order. These are machines with the ability to process information; steam engines that produce numbers, like the ones that Charles Babbage dreamed about.
So we have evolved our ability to think collectively by first gaining domain over matter, then over energy, and now over physical order, or information. Yet, this should not fool us to believe that we think, or that machines do. The large evolution of human thought requires mediated interactions, and the future of thinking machines will also happen at the interface where humans connect with humans through objects.
As we speak, nerds in the best universities of the world are mapping out the brain, building robotic limbs, and developing primitive versions of technologies that will open up the future where your great grandchild will get high by plugging his brain directly into the web. The augmentation that these kids will get is unimaginable to us, and is so bizarre for our modern ethical standards, that we are not even in a position to properly judge it (it would be like a sixteenth century puritan judging present day San Francisco). Yet, in the grand scheme of the universe, these new human machine networks will be nothing other than the next natural step in the evolution of our species' ability to beget information. Together, humans and our extensions—machines—will continue to evolve networks that are enslaved to the universe's main glorious purpose: the creation of pockets where information does not dwindle, but grows.