I've yet to get a hold of Michio Kaku's new book The Physics of the Impossible, and most likely it'll be a while before I get round to it. But I'm intrigued by the publicity it's been getting, and its possible implications for parapsychology.
Kaku is a theoretical physicist at City University in New York, and a big player in the field of string theory. He's also a pretty effective science popularizer. He has got big attention with this book, only published in the UK today, by arguing that a lot of wacky ideas we associate with science fiction may not be completely impossible after all.
Kaku puts forward three categories of 'impossibilities'. In reverse order, what he calls 'Type 3' include technologies that absolutely violate the known laws of physics, such as perpetual motion machines and precognition. These would require a fundamental shift in our understanding of physics. Type 2 are technologies currently at the edge of our understanding, but that might be possible one day, such as time travel.
Under Type 1, Kaku groups a number of things that are impossible today, but which do not violate the known laws of physics and so might one day become possible. These include: force fields, invisibility, phasers and death stars, teleportation, telepathy and psychokinesis, robots, UFOs and aliens, starships, antimatter and anti-universes.
This is a pretty eclectic mix of ideas, theories and technologies. As to his reasoning, I'm a bit in the dark, as I haven't read the book. I understand that Kaku argues teleportation in terms of quantum entanglement - it's being done on the level of particles, so the principle is already there. Alien contact becomes more probable as astronomers scan planets in other solar systems, so that too is feasible. Robots already exist. He talks of invisibility on the basis of new materials that eliminate reflections and shadows.
What gets my attention is the presence in the list of telepathy and psychokinesis. As I say, it'll be a while before I find out what his thinking is (comments welcome, in the meantime), but I'm guessing his approach is technology-based and that he proposes they will become possible when we figure out how to do them (in terms of parallel universes?)
Parapsychologists would have a couple of things to say about that: a) telepathy and psychokinesis are here now, and b) they don't involve technology. They would add that precognition, which Kaku thinks is really impossible, is closely associated with these things. But what interests me is how sceptics will respond. Normally they can't stand it when a high-profile scientists comes out in favour of telepathy, and they try to drown him out with a cacophony of jeering. I guess that won't happen here, though, because Kaku's idea of telepathy is precisely that it doesn't contradict known laws of physics, which is their main stated reason for objecting to it.
This is an interesting development. One outcome could be that Kaku's ideas could turn out to be too simplistic, and will be shot down by parapsychologists, pointing out that they don't relate to the considerable existing data. That would be a pity, although ironically since parapsychologists are so little regarded in the scientific community perhaps no one would notice. For even if the theory is not wholly convincing, it can only be a good thing if serious scientists bring psychism in the scientific arena. If the concept of telepathy can be raised without sceptics popping a fuse in public, perhaps the scientific world will start to calm down and talk about it rationally.