Secrets of the Quantum

The history of the quantum

The word quantum was derived from Latin around the year 1600. A quantum refers to a quantity or unit of something. A quantum of water, for example, would be a specific quantity of water. A quantum of wood would be a certain amount of wood. And so on. But we never hear the word quantum used in these contexts. That’s because the word is now very strongly associated with the context of physics, as in quantum physics. How did this happen? 

About 300 years after the word quantum was coined, physicist Max Planck was trying to figure out the relationship between an object’s radiation and its temperature. He came up with a solution, but the only way he could make it work was to assume that energy came in discrete chunks, and not as a continuity. He decided to call these discrete chunks of energy quanta, the plural form of the Latin word quantum. With this single decision, the now famous phrase quantum physics was born. 

Since then, quantum physics has gone on to reveal seemingly astonishing facts about the nature of our world, such as the fact that communication can occur instantaneously between objects separated by vast distances. The mathematical success of quantum physics, its unexpected strangeness, its contribution to technology, and the wide ranging press it receives has made it nearly impossible to now separate the word quantum from the understanding of physics.

Knowing this brief history serves to highlight the following important points:

• The concept of a quantum precedes the ideas of quantum physics by several centuries.

• The concept of a quantum is not limited to its common use in quantum physics.

• The incomplete understanding and application of the concept of a quantum in physics is what leads to the range of interpretations of quantum physics.

• The incomplete understanding of a quantum in physics is now being applied to other fields, which threatens to limit the perspective of new fields like quantum biology.

What exactly is a quantum? 

We already know that a quantum is a discrete quantity or unit of something, but what exactly is it that defines a discrete unit? Let’s take some common objects for consideration.

A refrigerator is a discrete unit. What defines it as a unit? Since all aspects of the refrigerator are designed to cool its contents, we could say the cooling function defines it as a discrete unit. The kitchen counter that is adjacent to the refrigerator would not be considered part of the unit that is a refrigerator because the counter’s function is not to cool. That’s pretty straightforward.

Another answer to what defines the refrigerator as a unit might be its physical boundary. We can measure the dimensions of the refrigerator and find that it is 33 x 30 x 70 inches. The external lines of that refrigerator then define it as a unit. We might place a box on top of the refrigerator, but it would not be considered part of the unit since it falls outside the lines of the physical boundary. This concept of a boundary is immensely important. It is essential to understanding what a quantum fundamentally is, within and beyond physics.

Let’s go back to the example of the refrigerator’s cooling function for a moment. If we say that the kitchen counter adjacent to the refrigerator is not part of the unit because the counter doesn’t cool anything, what we have done is identify another kind of boundary—a functional boundary. So whether we’re talking about physical boundaries, functional boundaries, or any other kind of boundary, it is a boundary of some kind that defines a unit.

Let’s consider another discrete unit—a dozen eggs. What is the boundary that defines a dozen eggs? In this case, the boundary is entirely conceptual. It does not relate to physical dimensions because the size of the eggs is irrelevant. It does not relate to a function because the function of the twelve eggs is irrelevant. The only boundary that matters here is the conceptual boundary of “twelve things.” Any twelve eggs, regardless of size, shape, color, function, quality, or any other condition, would qualify as a dozen.

Boundaries are everything, literally

In the preceding examples, we identified three different types of boundaries—functional, physical, and conceptual. Although the type of boundary varies in each case, it is clear that in each case the detection of some kind of boundary is the very reason we perceive a discrete unit. 

Note also that if this boundary were to be violated or invalidated, we would no longer detect the unit as is. For example, a refrigerator that has no cooling function is not a refrigerator, but rather a storage shelf that is no better than the adjoining kitchen counter or closet. We might still call it a refrigerator if the cooling function breaks down, because we still associate it with the function of cooling and we still expect it to cool again when it’s fixed, but if there were no cooling system installed to begin with, we would not consider it a refrigeration unit.

Similarly, if the physical dimensions of the refrigerator were to melt away, leaving an amorphous mass that melts into its surroundings, we also would not detect a discrete unit that we call a refrigerator.

And finally, if I tried to sell you eleven eggs while calling it a dozen, you would not accept my offer, just as I would not accept your offer if you asked me for twenty eggs in your dozen. In both instances, we’ve violated the accepted boundary of “dozen.”

These examples demonstrate that the presence of a boundary defines a unit of anything. A human being is a unit. A family is a unit. A liter of milk is a unit. An atom is a unit. The electromagnetic field is a unit. All of these can be considered quanta in the most fundamental sense of the word. In the context of physics, however, only things recognized by physicists as indivisible bundles of energy qualify as quanta. The scientifically-interpreted quantum of physics is a subsidiary of the original quantum.

How do we detect boundaries?

If we are talking about a physical boundary, you might say our eyes (and ultimately the brain) detect the boundary. If we are talking about a functional or conceptual boundary, you might say the brain alone detects the boundary. Regardless of the type of boundary, the brain is typically considered the ultimate detector of the boundary since the brain is thought to be the epicenter of cognition. This suggests that boundaries are inevitable and intrinsic to the world, because they exist in the form of discrete objects out there and are merely picked up by the brain. But is this the case?

The idea that discrete objects are intrinsic to the world and exist independent of observation is not a scientific conclusion, it is a philosophical interpretation called realism. Even though realism is unofficially the most popular scientific view, all the evidence we have gathered is also perfectly compatible with a much simpler, though less familiar, interpretation—the world is mental in nature, and discrete objects are experienced as they are only in relationship to an observer. The last two lines deserve a second read.