The uncertainty relation does not refer to the past; if the velocity of the electron is at first known and the position then exactly measured, the position for times previous to the measurement may be calculated.
Interpretation
This quote explains the concept that knowing an electron's position does not retroactively affect its velocity in the past.
Werner Heisenberg's statement highlights a key aspect of quantum mechanics known as the uncertainty principle. It emphasizes that while we can measure and know certain properties of particles, such as the position of an electron, this does not imply knowledge about its past states or velocity before the measurement, illustrating the limits of our knowledge in the quantum realm.
In practice
In a lecture on quantum physics, to explain the nuances of the uncertainty principle.
Although the theory of relativity makes the greatest of demands on the ability for abstract thought, still it fulfills the traditional requirements of science insofar as it permits a division of the world into subject and object (observer and observed) and, hence, a clear formulation of the law of causality.
It was about three o'clock at night when the final result of the calculation [which gave birth to quantum mechanics] lay before me ... At first I was deeply shaken ... I was so excited that I could not think of sleep. So I left the house ... and awaited the sunrise on top of a rock.
It is generally believed that our science is empirical and that we draw our concepts and our mathematical constructs from the empirical data. If this were the whole truth, we should, when entering into a new field, introduce only such quantities as can directly be observed, and formulate natural laws only by means of these quantities.
When I meet God, I am going to ask him two questions: Why relativity ? And why turbulence ? I really believe he will have an answer for the first.
The end of the First World War had thrown Germany's youth into great turmoil. The reins of power had fallen from the hands of a deeply disillusioned older generation, and the younger ones drew together in larger and smaller groups to blaze new paths or, at least, to discover a new star to steer by.
The Same organizing forces that have shaped nature in all her forms are also responsible for the structure of our minds.
We've been modifying the biological world at the level of DNA for thousands of years. Somehow there is this new fear of what we already have been doing and that fear has limited our ability to provide real solutions.
The smaller the planets are, they are, other things being equal, of so much the greater density; for so the powers of gravity on their several surfaces come nearer to equality. They are likewise, other things being equal, of the greater density, as they are nearer to the sun.
The fact that all Mathematics is Symbolic Logic is one of the greatest discoveries of our age; and when this fact has been established, the remainder of the principles of mathematics consists of the analysis of Symbolic Logic itself.
In the process of natural selection, then, any device that can insert a higher proportion of certain genes into subsequent generations will come to characterize the species.
Physical concepts are free creations of the human mind, and are not, however it may seem, uniquely determined by the external world.
Mathematics deals exclusively with the relations of concepts to each other without consideration of their relation to experience.
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