The Quantum Theory and Uncertainty Principles: Some Philosophical Implications

 

By: Abonyi, Hyginus Ebuka


1.0 Introduction

A German physicist named Max Planck, explained that radiation from a sparkling body changed its shades from red to orange to blue when the temperature was increased and it was known as black body radiation; the quantum hypothesis. Hence, comes quantum mechanics, which completely altered the fundamental precepts of physics.[1] Planck’s theory held that radiant energy is made up of particle-like components, known as “quanta.”[2]

Nonetheless, in 1927, in the field of quantum mechanics, another German physicist, Werner Heisenberg proposed the Uncertainty Principle. The uncertainty principle is certainly one of the most famous aspects of quantum mechanics[3] and it helped to establish the foundations of quantum physics. It has often been regarded as the most distinctive feature in which quantum mechanics differs from classical theories of the physical world. Nonetheless, the bone of contention in this article is the philosophical implication of Quantum Physic and Uncertainty principle. However, an exposition of quantum physic and uncertainty principle is first and foremost, exposed.

2.0 Exposition of Quantum Theory

Quantum theory (otherwise known as quantum physics or quantum mechanics) is one of the two main Planck’s of modern physics, along with general relativity, and between them the two theories claim to explain virtually everything about the universe. General relativity gives us our picture of the very big (space-time and gravity), while quantum theory gives us our picture of the very small (atoms and their constituents).

However, Planck had sought to discover the reason that radiation from a glowing body changes in color from red, to orange, and, finally, to blue as its temperature rises. He found that by making the assumption that energy existed in individual units in the same way that matter does, rather than just as a constant electromagnetic wave - as had been formerly assumed - and was therefore quantifiable, he could find the answer to his question.

The existence of these units became the first assumption of quantum theory. Planck wrote a mathematical equation involving a figure to represent these individual units of energy, which he called quanta. The equation explained the phenomenon very well; Planck found that at certain discrete temperature levels (exact multiples of a basic minimum value); energy from a glowing body will occupy different areas of the color spectrum. Planck assumed there was a theory yet to emerge from the discovery of quanta, but, in fact, their very existence implied a completely new and fundamental understanding of the laws of nature.

Nonetheless, Quantum theory is a modern physical theory concerned with the emission and absorption of energy by matter and with the motion of material particles. Just as the theory of relativity assumes importance in the special situation where very large speeds are involved, so the quantum theory is necessary for the special situation where very small quantities are involved, i.e., on the scale of  molecules, atoms, and elementary particles. Aspects of the quantum theory have provoked vigorous philosophical debates concerning, for example, the uncertainty principle and the statistical nature of all the predictions of the theory.

2.1 Relationship of Energy and Matter

According to the older theories of classical physics, energy is treated solely as a continuous phenomenon, while matter is assumed to occupy a very specific region of space and to move in a continuous manner. According to the quantum theory, energy is held to be emitted and absorbed in tiny, discrete amounts. An individual bundle or packet of energy, called a quantum (plural is quanta), thus behaves in some situations much like particles of matter; particles are found to exhibit certain wavelike properties when in motion and are no longer viewed as localized in a given region but rather as spread out to some degree.

2.2 Dual Nature of Waves and Particles

 The restriction of the energy levels of the electrons is explained in terms of the wavelike properties of their motions: electrons occupy only those orbits for which their associated wave is a standing wave (i.e., the circumference of the orbit is exactly equal to a whole number of wavelengths) and thus can have only those energies that correspond to such orbits. Moreover, the electrons are no longer thought of as being at a particular point in the orbit but rather as being spread out over the entire orbit. Just as the results of relativity approximate those of Newtonian physics when ordinary speeds are involved, the results of the quantum theory agree with those of classical physics when very large "quantum numbers" are involved.[4]

3.0 The Uncertainty Principle

Heisenberg’s uncertainty principle states that it is impossible to measure or calculate exactly, both the position and the momentum of an object. This principle is based on the wave-particle duality of matter. Although, Heisenberg’s uncertainty principle can be ignored in the macroscopic world (the uncertainties in the position and velocity of objects with relatively large masses are negligible), it holds significant value in the quantum world. Since atoms and subatomic particles have very small masses, any increase in the accuracy of their positions will be accompanied by an increase in the uncertainty associated with their velocities.

In the field of quantum mechanics, Heisenberg’s uncertainty principle is a fundamental theory that explains why it is impossible to measure more than one quantum variable simultaneously. Another implication of the uncertainty principle is that it is impossible to accurately measure the energy of a system in some finite amount of time. Heisenberg’s uncertainty principle states that for particles exhibiting both particle and wave nature, it will not be possible to accurately determine both the position and velocity at the same time.[5] The principle is named after German physicist, Werner Heisenberg who proposed the uncertainty principle in the year 1927.[6] 

A preliminary and simplistic formulation of the quantum mechanical uncertainty principle for momentum and position can be found in Heisenberg’s article of 1927, entitled as Über den anschaulichen Inhalt der quanten-theoretischen Kinematik und Mechanik as 

Im Augenblick der Ortsbestimmung… verändert das Elektron seinen Impuls unstetig. Diese Änderung istum so größer, je kleiner die Wellenlänge des  benutzten Lichtes, d. h. je genauer die Ortsbestimmung ist …also je genauer der Ort bestimmt ist, desto ungenauer ist der Impuls bekannt und umgekehrt”.[7] Translated into English: “When the position is determined… the electron undergoes a discontinuous change in momentum. This change is the greater the smaller the wavelength of the light employed, i.e., the more exact the determination of the position… thus, the more precisely the position is determined, the less precisely the momentum is known, and conversely.”

4.0 Philosophical Implications of Quantum Theory

4.1 On Epistemology

The epistemological question of how we can have knowledge of the properties of an object is answered in physics by the notion of observables. The notion of an object as the focus of determinative properties lies at the heart of classical realism –which is one of the main Western- common sense philosophical positions.[8] It is encoded in the structure of our language itself: the subject-predicate form of simple sentences reflects the idea of properties adhering to things, and plays a crucial role in determining how we understand truth; in particular, what is meant by true statement.

4.1.1 The Observableness

It is a measurement for a statement to be claimed as true. It is because the realism claims that the true statement or knowledge is what is in accordance with the object under observation. So, Quantum Physics that shows object on atomic level is in uncertain condition implies that there is no true statement that can be gained. What seems to be coming under increasing pressure, at least in the realm of quantum physics (and in cosmology as well) is the further and more specific claim of correspondence, that the structure of the theoretical concepts corresponds to some extent with the structure of their references in nature. Also the claim of convergence, that the sequence of these terms generated by successive theories stand in increasingly more accurate correspondence to these structure.

4.2 On Logic

It says that under Aristotelian logic, the statement is under two classifications: true or false, no intermediate. But under Quantum Physics with its wave-particle experience, it gives the intermediate-condition between false-true. It is because it cannot be said that the statement: the light is particle, is true and the statement: the light is wave, is false, or each as being true or false. But both are correct and it implies light is in intermediate condition between particle and wave. Though some say that it is just because of the limits of our language to describe a new phenomenon that is not under known classification, here is particle and wave.

Philosophical Implications of Heisenberg’s uncertainty principle

a.       Heisenberg was openly a subjective idealist as a student and fought against the workers in the revolution of Germany 1919. As a reactionary, bourgeois scientist advocating subjective idealism, his studies were even self-contradictory. Commencing from a rejection of science to a studying of the world and that to concluding illegitimately his idealist presumptions, that the world is unknowable, he maintains his bias against the facts.

b.      The uncertainty principle embodies indeterminism at the subatomic level. The possible implication is that a perfect knowledge about a particle state cannot be achieved which implies indeterminism specially in case of chaotic systems in which any tiny change of initial conditions may result in a completely different final result of the system evolution.

There are other two implications[9] - one is ontological, the other is epistemological.

Ontology and epistemology are the two branches of metaphysics. Ontology tells us what there is and epistemology tells us how we know what there is. Ontology therefore relates to reality and epistemology relates to consciousness. Note that Metaphysics is about the relationship between reality and consciousness.

There is nothing mysterious about the uncertainty principle – it simply declares the fact that when we try to measure position and momentum, we can establish either one or the other but not both. This is because we can’t establish one without disturbing the other. This uncertainty relates to what we can and cannot know – so it is a question of epistemology. Our inability to know both position and momentum is an epistemological issue. The philosophical implications of this limitation depend entirely on your ontology; in other words, they depend on the philosophical assumptions embodied in your view of reality. If you subscribe to realist ontology, then you believe reality exists independently of consciousness.

Realists therefore believe a particle actually has both position and momentum regardless of whether you attempt to measure them. The fact that it is not possible to state with total accuracy both the position and momentum of a particle leaves realists in a predicament. On the one hand, they cannot reject the reality of these variables – on the other, if these entities can’t be simultaneously measured, do they really exist? Whether or not a particle actually has both position and momentum is an ontological issue.

If, however you adopt non-realist ontology, one that sees matter as dependent on mind, then this ontology does not view a particle as something that actually has both position and momentum prior to any attempt at measurement. In this view of reality, position and momentum are quantities that are created as and when they are measured – and not before. With this ontology there is no uncertainty – there is only the inexorable fact that we can’t establish position and without disturbing momentum and vice-versa.

Non-realist ontology does not therefore require an uncertainty principle. So, whether or not the uncertainty principle has philosophical implications depends entirely on your ontology – and on the assumptions embodied in it. Realists have had to postulate the (ontological) uncertainty principle to explain away the (epistemological) difficulty in measurement.

The choice is yours: an ontology that gives rise to epistemological difficulties – or one that doesn’t. Of course realist / materialist beliefs are so entrenched, that they’re not going to be relinquished overnight. Even, so I look forward to seeing what science might achieve, once it shakes off the shackles of its realists preconceptions. In a sense, this is already happening in QM where many of the concepts it is currently exploring are ‘accommodations’ it is being forced to embrace in order to adapt its realist foundations without ostensibly abandoning them.

5.0 Conclusion

Notwithstanding the implications of Quantum theory and uncertainty principle, Quantum theory is used in a huge variety of applications in everyday life, including lasers, CDs, DVDs, solar cells, fibre-optics, digital cameras, photocopiers, bar-code readers, fluorescent lights, LED lights, computer screens, transistors, semi-conductors, super-conductors, spectroscopy, MRI scanners, etc, etc. By some estimates, over 25% of the GDP of developed countries is directly based on quantum physics. It even explains the nuclear fusion processes taking place inside stars. In the other hand, uncertainty principle, in its most common form, states that there’s a fundamental relationship between our knowledge of a quantum particle’s position and momentum of a physical system. Rather, these quantities can only be determined with some characteristic “uncertainties” that cannot become arbitrarily small simultaneously.[10]

 

Endnotes



[1] Quantum Theory. The Columbia Electronic Encyclopedia®. 2013. Columbia University Press 21 Apr. 2022 https://encyclopedia2.thefreedictionary.com/quantum+theory

[2] History.com Editors. “The birth of quantum theory”. History,  A&E Television Networks, July 21, 2010, https://www.history.com/this-day-in-history/the-birth-of-quantum-theory

[3] Hilgevoord, Jan and Jos Uffink, "The Uncertainty Principle", The Stanford Encyclopedia of Philosophy (Winter 2016 Edition), Edward N. Zalta (ed.), URL = <https://plato.stanford.edu/archives/win2016/entries/qt-uncertainty/>.

[4] Abhay Ashtekar, T. S. (1998). Geometrical Formulation of Quantum Mechanics. In A. Harvey, On Einstein's Path  (pp. 23-63). New York: Springer-Verlag.Albert, D. (1992)

[5] Heisenberg, W.K. The Physical Principles of Quantum Theory. University of Chicago Press, Chicago, 1930, 15-19.

[6] W. JohnWheeler. Quantum Theory and Measurement. Princeton: Princeton University Press. Maudlin, T. (1994)

[7] Kennard, E.H. (1927) Zur Quantenmechanik einfacher Bewegungstypen.  Zeitschrift für Physik, 44, 326-352.http://dx.doi.org/10.1007/BF01391200

[8] Jonathan Power. Philosophy and the New Physics, Rutledge, New York , 1991. P.54

[9] Barukčić, I. (2014) Anti Heisenberg—Refutation of Heisenberg’s Uncertainty Principle. International Journal of Applied Physics and Mathematics, 4, 244-250. http://dx.doi.org/10.7763/IJAPM.2014.V4.292

[10] Phillips, Thomas. The Mathematical Uncertainty Principle. (2005, November). Retrieved May 27, 2020, from American Mathematical Society: http://www.ams.org/publicoutreach/feature-column/fcarc-uncertainty

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