'The fundamental laws are already known, and Kaku tells us we’ll soon be manipulating the stuff of consciousness with the same acuity we push electrons around in our digital devices. This singular confidence is both strength and weakness as Kaku unspools his narrative, and doubts about his core convictions begin to trail the reader like a parade of ghosts.
'Kaku takes us to laboratories where researchers are studying the microscopic dynamics of the brain’s wiring. For example, using functional magnetic resonance imaging (fMRI), which tracks neural activity, researchers have recorded how the brain lights up when shown fragments of a video. Scientists can then determine a subject’s neural response to seeing various things. Comparing this dictionary of neural responses to the observed fMRI patterns in a person viewing a different film, researchers can reconstruct a reasonable facsimile of the film based purely on brain activity. With this kind of technique it may even be possible for scientists to crudely identify what people hooked to fMRI machines are dreaming about.
'From these developments, Kaku imagines an era when memories can be recorded and then played back into someone else’s head by stimulating the same pattern of neural activity. Going one step further, machines wired directly to brains will be able to read and transmit our thoughts instantaneously.
Minds made of meat (ours) are just one of Kaku’s concerns. He is also interested in the possibilities of silicon and even alien minds. A compelling chapter on artificial intelligence describes the explosion in robotics and the new research that seeks to broaden the requirements for silicon self-consciousness, including a capacity to feel emotion.'