137 - Arthur I. Miller [99]
So can there be predictability, that is, causality, in quantum mechanics? The conservation laws of energy and momentum state that the amount of energy and momentum in a system cannot change. Scientists can apply these laws to predict the final condition of a system from its initial state.
If a quantum of light striking an electron is like two billiard balls, then it should be possible to use the laws of conservation of energy and momentum to work out where to set up instruments to detect the light quantum and the electron after they collide. In quantum physics the law of causality of classical physics—which requires precise measurements of position and momentum in the same experiment—is replaced by predictions made by the laws of conservation of energy and momentum.
A new mandala
In response to Jung’s analysis of his dream, Pauli commented that he agreed that the stranger conveyed a holistic view of nature quite different from the “conventional scientific point of view.” Unlike his colleagues, Pauli wrote, he considered the quantum mechanics as incomplete. What was required was a fusion with psychology. He had “no shortage of ‘not-yet-assimilated thoughts’,” he added wryly.
He disagreed, however, with Jung’s mandala primarily because it showed space and time as separate, whereas scientists understood that they were one—the space-time continuum. He suggested another one which included space-time while retaining the psychological element of Jung’s:
Pauli’s suggested improvement to Jung’s mandala.
Here he lays out complementary pairs, causality—the chain of cause and effect—against synchronicity; and conservation of energy against the space-time continuum, in agreement with Bohr’s complementarity principle. Classical physics pairs causality with a description in space and time. But this is an idealization. And so Pauli set in its place the law of conservation of energy; to be more precise the law of conservation of momentum should be included too.
Synchronicity in physics and psychology
The essential question Pauli felt needed to be asked was, “How do the facts that make up modern quantum physics relate to those of other phenomena explained by [Jung] with the aid of the new principle of synchronicity?” How did quantum physics sit in relation to synchronicity and other psychological phenomena. Both types of phenomena, he noted, went beyond “classical determinism.”
In Pauli’s mandala, energy and space-time, and causality and synchronicity, are complementary but mutually exclusive, like light and dark and life and death. Both arms are necessary. It is the tension between them that gives physical meaning to reality.
Pauli also noted that when Jung used “physical terms to explain psychological terms or findings,” to Jung these were “dreamlike images of the imagination.” Jung, for example, referred to radioactivity as a physical analogy for a coincidence in time—total nonsense to a physicist. Pauli proceeded to explain to Jung the notion of probability in quantum physics using radioactive decay.
In quantum physics there is a law for determining how many of a large sample of nuclei will undergo radioactive decay by emitting particles and light. But it cannot determine at what precise point in time a single nucleus will decay because it is impossible to investigate a single atom and how it develops in space and time. In other words, individual events are outside of the chain of cause and effect.
On average, half the total sample will decay in the “half-life”—a period of time that is a characteristic property of each radioactive element. After another half-life, another half of the sample will decay. But it is impossible to know when any particular nucleus