The Physical Worldornament
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The Restless universe
Introduction to The restless Universe

1 The lawful Universe

2 The clockwork Universe

3 The irreversible Universe

4 The intangible Universe

5 The uncertain Universe

6 Closing items


Other titles in the Physical World series

Describing motion

Predicting motion

Classical physics of matter

Static fields and potentials

Dynamic fields and waves

Quantum physics: an introduction

Quantum physics of matter

Answer and comments

See Question 1.6 with its relevant text

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Question 1.6
In Section 1 it was said that the notion of scientific law was based on the fact that identical situations produced identical outcomes. To what extent does this remain true in quantum physics where identical experiments may produce different outcomes?

Q1.6 In quantum mechanics, identical situations do not always produce identical outcomes. Nevertheless, a certain regularity remains because if an experimental arrangement has a variety of possible outcomes, each occurring with a definite probability, subsequent repetitions of the experiment will have the same outcomes occurring with the same probabilities. By repeating the experiment a large number of times we can check whether the probabilities predicted by quantum mechanics are valid. The most important characteristic of a scientific law is that it should be open to experimental tests. Quantum mechanics has introduced a new type of scientific law - one based on probability which embraces the fact that identical situations do not produce identical outcomes.

See Question 1.6 with its relevant text

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