I stumbled across this book while browsing the shelves at my local library. The book is The Science Gap: Dispelling the Myths and Understanding the Reality of Science by Milton A. Rothman. There have been many books written to debunk various theories in pseudoscience. The best of these is Carl Sagan's Demon-Haunted World, which I read years ago and which greatly influenced my thinking (it was Sagan who persuaded me to quit watching programs about crop circles and the Loch Ness monster that I was so fond of as a child). However, Rothman's book is different in that in focuses not on specific pseudoscientific theories, but rather on myths about the nature of science itself. These myths are sayings often used by science-fiction writers to justify fantastic predictions about the future, such as "Nothing is impossible", "Any theories we believe today are likely to be overturned in the future", and "Advanced civilizations of the future will have the use of forces unknown to us at present." Rothman was the perfect person to write a book like this, because in addition to being a professional research physicist, he was also an avid science-fiction fan and writer. In fact, he was a co-founder of the Philadelphia Science Fiction Society, and he also ran his own fanzine called Milty's Mag. In one autobiographical article, Rothman talked about how his love of science-fiction inspired him: "I was already determined to do something about bringing the wonders of science fiction into reality ... My eyes were set on a higher purpose: becoming a scientist." So he was not hostile toward science-fiction, just tempered by the realities of a career in scientific research. He begins the book by discussing the distinction between metaphysical idealism and metaphysical realism, and pointing out that modern science is firmly grounded in realism, specifically, the position of ontological reductionism. That is, the assumption that everything is made of fundamental particles that obey the laws of nature, and that there is nothing else. Having laid this foundation, he goes on to explain how the Standard Model of particle physics allows us to make the negative prediction that no new forces strong enough to have macroscopic effects will be discovered in the future. This stems from the fact that forces are understood to be mutual interactions between two particles, and that new forces would require the creation of new particles which do not exist in our present universe. Furthermore, out of the four known forces -- gravity, electromagnetism, and the strong and weak nuclear forces -- only electromagnetism is within human ability to control, owing to the fact that there are two kinds of electrical charges. We are unable to manipulate gravitational fields because there is only one kind of mass. Nor is there anything we can do to manipulate the nuclear forces. All of the great technological developments of the past century are the result of our knowledge of electromagnetic fields. The sobering conclusion to all this is that there may be an ultimate limit to how far technology can advance, based on how far we can exploit the electromagnetic interaction. The other conclusion is that James Clerk Maxwell was one of the most influential people in human history. Carl Sagan echoed this thought in the closing chapters of Demon-Haunted World when he wrote that Maxwell had "done more to shape our civilization than any ten recent presidents and prime ministers." Rothman concludes his book by making a series of negative predictions about the future. The predictions are based on the fundamental symmetries of nature, and the principle (from ontological reductionism) that these symmetries apply to all particles, and to all objects built up out of particles, everywhere in the universe. Nobody is ever going to build a perpetual motion machine (or equivalent device). (Conservation of energy) Nobody is ever going to hang levitated between floor and ceiling without material support or other physical force such as magnetic fields. (Conservation of momentum) Nobody is going to travel to the distant stars at speeds faster than that of light. (Principle of relativity; Poincare symmetry) Nobody is going to send messages of any kind at speeds faster than that of light. (Poincare symmetry) Nobody is going to send any kind of message that does not get weaker as it travels away from the source. (Heisenberg uncertainty and conservation of energy) Nobody is going to send any message through space without the transmission of energy by a physical carrier (particle or photon). (Conservation of energy) Nobody is going to send messages directly from one mind to another. (At least not without an amplifier. Electromagnetic fields produced by the brain are too small to carry signals over any appreciable distance, and no other signal carrier is known.) Nobody is going to receive messages directly into his/her mind without the agency of a physical carrier. (This includes perception at a distance as well as perception of future events.) For me, the best quote in the book is from the chapter dealing with the myth that "Scientists don't have any imagination": Any scientist who refuses to waste time poring over the blueprints for a proposed perpetual motion machine is acccused of having a closed mind. Any scientist who ignores claims for ESP or UFOs or faster-than-light travel is accused of a deficiency of imagination. I suggest that the opposite is true. It takes very little imagination to believe naively that anything is possible. Any ten-year-old child can believe this. It takes a great deal of knowledge to know what things are possible and what things are impossible. A retrospective look at the lives of the most productive scientists indicates that each one had an interesting and hard-to-explain ability: a knack of choosing lines of research that led to important results. These scientists avoided new ideas that were so premature or so unfocused that nothing could be done with them ... What the successful scientists did was to use their imaginations to decide on research topics that were on the cutting edge: problems that could be solved with the tools at hand or with tools that they could invent, and which were broad enough to represent important advances in knowledge. All in all, The Science Gap is a highly informative, well-written and powerfully argued book. I am surprised that it is not more widely known. Anyone studying science should be familiar with the facts and ideas presented here.