Einstein's Unfinished Revolution: The Search for What Lies Beyond the Quantum (Lee Smolin, 2019)

Quantum physics principles

1. If we know both A and B at a given time, we could precisely predict the future of the system.
2. We can choose to measure A or we can choose to measure B; and in each case we will succeed. But we can’t do better. We cannot choose to simultaneously measure both A and B.
3. Given the quantum state of an isolated system at one time, there is a law that will predict the precise quantum state of that system at any other time.

Uncertainty principle

1. (Uncertainty in A) x (Uncertainty in B) > a constant
2. (Uncertainty in position) x (Uncertainty in momentum) > a constant

Superposition principle

1. Any 2 quantum states may be superposed together to define a third quantum state. This is done by adding together the waves that correspond to the 2 states. This corresponds to a physical process that forgets the property that distinguished the 2.

Born rule

1. The probability of finding the particle at a particular location in space is proportional to the square of the height of the corresponding wave at that point.
2. The outcome of a measurement can only be predicted probabilistically. But afterward, the measurement changes the quantum state of the system being measured, by putting it in the state corresponding to the result of the measurement. This is called collapse of the wave function.

Pearle

1. Continuous spontaneous localisation (CSL): collapse occurs often for microscopic systems containing many atoms.

Quantum poincare recurrence theorem: quantum state will return arbitrarily close to its initial state.

Principal principle

1. It is most rational, in a situation where you have limited knowledge, to choose to align your subjective betting odds with the frequencies observed in the historical record.

Principles for fundamental physics

1. Background independence
2. Space and time are relational
3. Principle of causal completeness
4. Principle of reciprocity
5. Principle of the identity of indiscernible

Hypotheses that lies beyond spacetime and quantum

1. Time, in the sense of causation, is fundamental
2. Time is irreversible
3. Space is emergent