Product Description

Nobel Prize winner Werner Heisenberg's classic account explains the central ideas of the quantum revolution, and his celebrated Uncertainty Principle. Heisenberg reveals how words and concepts familiar in daily life can lose their meaning in the world of relativity and quantum physics.This in turn has profound philosophical implications for the nature of reality.

Product Details

• Amazon Sales Rank: #80399 in Books
• Published on: 2000-08-03
• Original language: German
• Binding: Paperback
• 176 pages

About the Author
Werner Heisenberg's celebrated Uncertainty Principle is one of the cornerstones of modern physics. He was awarded the Nobel Prize in 1932 and received numerous other awards. As a public figure he actively promoted the peaceful use of atomic power, and in 1957 led other German scientists in opposing a move to equip the West German army with nuclear weapons. He died in 1976. Paul Davies is the author of many books, including God and the New Physics and The Fifth Miracle.

Customer Reviews

Quantum theory explained by the master for the masses
Heisenberg explains the basics of quantum theory in his own words (rather than by formulas) making it also accessible to people with little knowledge of mathematics or physics. In addition he provides a to-the-point elaboration on the enormous implications his findings have for science in general. The excellent introduction of Paul Davies is the icing on the cake.

Fantastically easy to read, although a bit disappointing in the philosophy department
I may have read too much into the title of this book, the key words are 'and' and 'revolution'. The book compares the "revolutions" in modern physics to those in ancient philosophy, and does so in a very straightforward and easily digestible manner. My only disappointment really is that I was hoping to read more on the philosophical implications of modern physics, and the book was rather light on that. Still, the physics is handled deftly and well explained, and the philosophy appears to be well understood (although I must admit I'm not that familiar with ancient philosophers).

All in all, a very enlightening short read.

Existence and physical reality according to physicist Werner Heisenberg
At the turn of 20th century when quantum physics was born; the founding fathers of this scientific revolution were thinking deeply about the philosophical consequences of the new physics in terms of existence and physical reality (ontology). The reality perceived through the laws of classical physics provided strong challenges to quantum reality and human knowledge of quantum physical concepts (epistemology). In addition, the theory of relativity, which also came into existence at about the same time, altered the concept of space and time (consequently their relationship to matter, and the concept of gravity) radically from the existing knowledge of Newtonian physics. In this book, physicist Heisenberg gives a brilliant account of physical reality after reviewing the works of notable philosophers like; Kant, Descartes, Locke, Berkeley, and Hume. You get to read the physical and philosophical analysis of one of the founding fathers of quantum physics using both classical and quantum physics. His philosophical ideas are summarized below:

Physical theories had to be proposed speculatively and pursued deductively with respect to their many consequences that can be put to theoretical and experimental verifications. It turns out that the theory makes more physical and philosophical assumptions than the facts alone imply. The assumptions could be ontological or epistemological in nature. For example, the concept of space and time (and its relation to matter) is independent of the observer, which would be ontological in nature since the subject matter of scientific knowledge is independent of the perceiver (consequences of relativity). The nature of quantum physics introduces indeterminacy to nature of things which would be epistemological since the experiment performer (and knowledge-seeker) influences the subject matter (the outcome his experiments) by his physical observation. The state of a quantum object is undetermined until an observation is recorded. Hence, the author's argument is that the potentiality is a part of physical reality. Einstein's contention was that the potentiality, probability or chance is due to epistemological limitations of our knowledge in knowing the entire picture, the Omni-complete, and hence misapplied to the object itself. The Omni-complete object is omniferous, omnifarious, omniparous, omnipotent and omniscient and therefore the concept of chance or probability is inappropriate in the description of a real object. Both Einstein and Heisenberg admitted that the experimental data does not lead to concepts of physics, and hence the object of scientific knowledge remains unknown, but it is known through the theoretical constructs or axiomatic postulation verified indirectly by experiments and its deduced consequences. To find the object of scientific knowledge one must go to the theoretical assumptions of a physical law; the concept of probability and chance figures into the definition of the state of a physical system (due to statistical nature of things, and also use of statistical analysis in understanding the results of an experiment) in both classical and quantum physics. In quantum physics it also figures in the subject matter, but not in classical physics. This is the major difference between two disciplines that separated Einstein from Copenhagen school of thought. Author Heisenberg suggests that the concept of potentiality very much a part of subjective reality contrary to classical reality.

The probability function represents a mixture of two things, partly a fact and partly our knowledge of a fact. An atom consists of a nucleus and electrons (wave) moving around the nucleus; from the classical standpoint it is difficult to conceive how an electron orbit around the nucleus without changing its energy. Then again the electron is a wave until detected; therefore the energy is constant as long as it stays in the same orbit. The second point is that the act of determining the position becomes a measurement problem since light quanta is absorbed during its detection and the electron is displaced (change its position) to a higher electronic state. Thus the spacetime descrip¬tion of the atomic events is complementary to their deterministic description. The probability function obeys equations of motion as in Newtonian mechanics; its change in the course of time is completely determined by the quantum mechanical equation, but it does not allow a descrip¬tion in space and time. The observation, on the other hand, enforces the description in space and time but breaks the determined continuity of the probability function by changing our knowledge of the system. The mechanism and the results of an observation of atomic events can be described in classical concepts, but the deductions from observations results in probability functions which combines the statements about possibilities with statements about our knowledge of facts. Therefore we can not completely objectify the results of an observation. What happens between an observation and the next depends on the way we observe or on the fact we observe. This becomes subjectivism. Since the probability function combines objective and subjective elements. It contains statements about possibilities or better tendencies ("potentia" in Aristotelian philosophy), and these statements are completely objective, they do not depend on any observer, but it contains statements about our knowledge of the system, which of course are subjective in so far as they may be different for different observers. In ideal cases the subjective element in the probability function may be practically negligible as com¬pared with the objective one.

1. Uncertainty: Einstein, Heisenberg, Bohr, and the Struggle for the Soul of Science
2. What is Life?: With Mind and Matter and Autobiographical Sketches (Canto)
3. Schrodinger: Life and Thought
4. Niels Bohr's Times: In Physics, Philosophy and Polity