# “Wave-Packet Reduction” and the Quantum Character of the Actualization of Potentia

## Abstract

**:**

## 1. Introduction

## 2. Heisenberg’s Analogy

Citing this comment, Karl Popper later claimed that the “ ‘transition from the possible to the actual’ …Heisenberg himself …admits …is not a quantum effect” [7]. We may now ask: Is this so? Is there a basis in Heisenberg’s treatment of quantum mechanics for such a claim about the actualization of potentia?“If the observer later registers a certain behavior of the measuring apparatus as actual, then the mathematical representation changes discontinuously because a certain one among the various possibilities has proved to be the real one. The discontinuous “reduction of the wave packets,” which cannot be derived from Schrödinger’s equation, is a consequence of the transition from the possible to the actual. It is exactly analogous in Gibbs’ thermodynamics to a measurement restricting a system from a large ensemble to a smaller one.”([1], p. 27)

## 3. Is the Actualization of Potentia Classical?

## 4. Quantum State Change and Measurement

“Of course, it is entirely justified to imagine this transition, from the possible to the actual, moved to an earlier point of time, for the observer himself does not produce the transition; but it cannot be moved back to a time when the compound system was still separate from the external world [, which would] not be compatible with the validity of quantum mechanics for the closed system”.([1], p. 27)

## 5. Measurement without the “Cut”

## 6. The Actualization of Potentia Is Quantum

“Perhaps one might say that [potentiae] represent an intermediate between the possible and the factual, which can be called objective at most in the same sense as the temperature in the statistical theory of heat. This definite knowledge of the possible gives some definite predictions, but as a rule conclusions can only be drawn about the probability of a future event.”([20], pp. 54–55)

In both cases, it is also that there is no deterministic connection between the discovered state of the measured system and its previous description that is accessible via the fundamental deterministic equations of the respective theories.“The characterization of a system by a Hilbert vector is complementary to its description in classical terms, similar to the way that a microscopic state is complementary in Gibbs’ thermodynamics to the statement of the temperature.”([1], p. 27)

Upon the completion of measurement, new information is available to the observer, allowing a better fitting ensemble assignment and, therefore, more accurate predictions than provided via Equation (5).“The discontinuous change is naturally not contained in the mechanical equations of the system or of the ensemble which characterizes the system…the characterization of a system by an ensemble not only specifies the properties of this system, but also contains information about the extent of the observer’s knowledge of the system.”([1], p. 26)

## 7. The Role of the Actual

It is only that such a false impression may arise because constraints on our ability to measure the full set of properties of quantum systems render its state incompletely inaccessible; our knowledge of their objective being at any given instant is always limited.“The criticism of the Copenhagen interpretation of quantum theory reflects an anxiety that with this interpretation, the concept of ‘objective reality’ which forms the basis of classical physics might be driven out of physics. As we have shown here, this anxiety is groundless, since the ‘actual’ plays the same decisive part in quantum theory as it does in classical physics.”[1]

“…in the kinematic interpretation of thermodynamics [the degree of accuracy] always expresses [only] our lack of knowledge of the system concerned. But in quantum theory, ignorance of the result of future experiments can be compatible with the complete understanding—in the usual accepted sense—of the state of the system concerned. …in Heat, [by contrast,] ignorance about the results of certain experiments is always identified with ignorance of the true state of the system [itself] and is shown up in all experiments.”([21], pp. 50–51)

## 8. Conclusions

## Acknowledgments

## Conflicts of Interest

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Jaeger, G.
“Wave-Packet Reduction” and the Quantum Character of the Actualization of Potentia. *Entropy* **2017**, *19*, 513.
https://doi.org/10.3390/e19100513

**AMA Style**

Jaeger G.
“Wave-Packet Reduction” and the Quantum Character of the Actualization of Potentia. *Entropy*. 2017; 19(10):513.
https://doi.org/10.3390/e19100513

**Chicago/Turabian Style**

Jaeger, Gregg.
2017. "“Wave-Packet Reduction” and the Quantum Character of the Actualization of Potentia" *Entropy* 19, no. 10: 513.
https://doi.org/10.3390/e19100513