You might be forgiven for thinking that quantum mechanics doesn’t affect you in any way. Quantum theory only applies to objects at tiny scales, after all. Life is just fine and dandy using Newton’s classical physics to describe everything around us. But doing so would deprive ourselves of a unique perspective on life. In classical theory, our lives are pre-determined. Quantum mechanics transforms us from mere observers into meaningful players in the universe, giving us back our free will.
Origins of Quantum Theory
The source of countless discoveries, the scientific method remains to this day our best tool in humankind’s quest for knowledge. Theories are systematically and rigorously put to the test and promptly discarded when they fail. This approach led Isaac Newton to discover the Laws of Motion. Thanks to Isaac, we can mathematically describe an object falling from a tree, the same laws that govern how Earth revolves around the Sun. These laws would be known as ‘classical’ mechanics, able to describe all forms of matter. Classical mechanics is comforting to us as its laws apply to us, affecting how we behave and think about the world.
Early in the 20th century, several (now famous) experiments were performed that probed the behavior of matter at the atomic level. The results went against the laws of classical mechanics, but the experiments were sound. The experiments showed that particles could also behave as blurred versions with no fixed position. Forced to discard what they knew about classical mechanics, scientists created an entirely new set of physical laws, dubbed ‘quantum’ mechanics. This new theory yielded extremely accurate predictions when it was put to the test, confirming the quantum nature of the reality in which we live. However, quantum mechanics has big implications that affect our lives, especially in the area of determinism and free will.
Probability Defines Quantum Mechanics
As opposed to the concept of particles moving in set trajectories (that most of us can relate to), quantum objects are best described as waves. These waves represent a series of ‘states’ in which the object can exist. Each state is assigned a probability, such that when the object is eventually observed, it appears as a single, tangible particle with well-defined properties. The probabilities associated with each state can change with time or other external influences, but together they describe the behavior of the object in its entirety.
For example, we can measure the distance between two atoms in H2, a diatomic molecule of hydrogen. States exist in which the two atoms are exceedingly close together, as well as infinitely far apart. Most states, however, will correspond to the atoms being a comfortable distance from each other, not too near and not too far away.
The probabilities converge to a point of lowest energy, where we are most likely to observe the molecule if we chance a peek at it. But of course, there is also a small chance that we find them extremely close together or far apart. The idea that simple probability determines behavior is not confined to small, sub-atomic particles. Because everything is made up of such sub-atomic particles with quantum properties, this phenomenon extends to macroscopic objects that we can see and touch as well. Quantum physics transforms the world we live in from a series of mechanical processes to one that is governed by probability alone.
Observation Makes it Real
The magical and weird thing about having this uncertainty is that if we do not actively measure the interatomic distance between two atoms, they simultaneously occupy all possible distances at the same time (a la Schrodinger’s cat)! A thought experiment by Einstein involves a world in which nobody looks up at the moon at night. The unobserved moon starts to take on more and more states, ‘smearing’ its real position in relation to Earth. This is, of course, until an observer (a mouse, in Einstein’s world) looks up and says ‘aha! it is right there’.
By this principle, the mouse, the planet, and indeed everything in the Universe consists of ‘smears’ of probabilities. While the entire concept of quantum mechanics relies on the mathematics of probability, it is the simple act of observation that provides us with tangible, empirical outcomes.
This is not the case with classical mechanics, in which the observer plays no part in the process. Objects move and go about their business governed solely by the universal laws of motion, oblivious to our presence. In quantum mechanics, the observers are very much intertwined with reality. While the mathematical descriptions of this claim warrant an entire area of research, quantum mechanics also profoundly affect how we think about life.
Philosophical Implications of Quantum Mechanics
What Does it Mean to Observe?
If observation defines reality, is there more to the world than what is limited by our senses? And perhaps more importantly, does anything really happen if it isn’t observed? These are just two questions about how quantum mechanics affect us have yet to be answered.
Empirical evidence forms the basis of knowledge and logical thinking. We make decisions based on what we can see, touch, hear, taste and feel. In the quantum world, acquiring empirical data must disturb, or perhaps even bring into existence, the values that we observe. This doesn’t mean that what we observe is wrong, but that we cannot disentangle ourselves and our own perspectives from what we perceive as reality.
Werner Heisenberg, one of the founding fathers of quantum mechanics, once said ‘what we observe is not nature in itself but nature exposed to our method of questioning’. Our senses can only tell us so much; who knows what other facets of reality exist beyond our comprehension? What this also suggests is that while the ‘true’ nature of reality (regardless of whether or not such a concept exists) remains hidden from us, quantum mechanics tells us that our observations are no less valid in our description of reality.
To quote Neils Bohr, physicist and another pioneer of quantum theory: ‘There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature.’
How it Affects Determinism and Free Will
Quantum mechanics also puts the concept of free will into question. As humans, are we placed on a defined path before birth; can we not change our destiny? When Newton’s accurately predicted the path of planets with his laws of motion, he inadvertently transformed the universe into a fundamentally deterministic one. That is, if we have all the physical information about an object, we can calculate its past, present and future using Newton’s equations. Being physical objects, this extends to us; our entire lives would also be pre-determined. There would be no such thing as free will.
The link between classical mechanics and behavior inevitably leads to some moral dilemmas. If everything about your life was set in stone at the beginning of the universe, can you really be held responsible for any of your actions? Remember that under classical mechanics, rational thought and moral values are unable to influence the motion of particles that power your consciousness.
Quantum mechanics has the power to free us from the shackles of Newton. Let’s assume the thoughts and ideas in our brains are also subject to the processes of quantum mechanics. In this case, our choices are in states of superposition or ‘fuzziness’ until we consciously probe them. This conscious probing counts as an act of observation, producing an outcome in the form of a decision.
This transforms our mental constructs, our thoughts and choices, into a part of the same reality that we observe with our senses. Thus, our decisions are not pre-determined by the state of the universe, rather they are formed by the completely probability-based process of quantum mechanics!
The Quantum Nature of Life
Quantum mechanics provides us with a framework for turning our mental impetus into physical realities. As mentioned above, the act of observation is a fundamental principle of the quantum world. By observing a process, we reveal new insights that transcend existing values. Reality is as much constructed around us, as it is ourselves who give meaning to this reality!
The philosophical discussions arising from such a theory are extensive, and as such, continue to this day. ‘He does not play dice’, Albert Einstein famously wrote to Max Born in 1926. ‘He’ referring to Einstein’s concept of god—a collection of all the laws that govern our universe. Einstein was very much a realist, with an absolute belief in empirical methods and their results. The indeterminism and uncertainty surrounding quantum mechanics disturbed him greatly.
On the other hand, the indeterminate nature of quantum mechanics can bring meaning to our lives by redefining free will. The act of observation also contributes to what we perceive as physical reality. Just by being observers of the universe, we are able to shape the very fabric of it. However we look at it, quantum mechanics affects us in very real and profound ways.
Reference
- Zeilinger, A. (1999). A foundational principle for quantum mechanics. Foundations of Physics, 29(4), 631-643.
- Stapp, H. P. (2017). Quantum theory and free will: How mental intentions translate into bodily actions. Springer International Publishing. https://doi.org/10.1007/978-3-319-58301-3
About the Author
Sean is a consultant for clients in the pharmaceutical industry and is an associate lecturer at La Trobe University, where unfortunate undergrads are subject to his ramblings on chemistry and pharmacology.
