Secrets weary of their tyranny: tyrants willing to be dethroned.
The claim that “no one understands quantum mechanics” is often attributed to Richard Feyman, who said that to illustrate the perceived “randomness” that is at the heart of quantum mechanics and the Copenhagen Interpretation of QM. The unfortunate consequence of this phrase is that we now have people using it to claim that we know NOTHING about QM, and that no one understands it.
Without even going into what QM is, let’s consider the following first and foremost: we have used QM to produce a zoo of devices and techniques ranging from your modern electronics to medical procedure such as MRI and PET scans, etc. Already one can question whether this is a symptom of something that no one understands? When was the last time you place your life and the lives of your loved ones in something that NO ONE understands? That is what you do when you fly in an airplane or drive in a car that nowadays use modern electronics. All of these depend on QM for their operations!
The issue here is what is meant by the word “understand”. In physics, and among physicists, we usually consider something to be “fully understood” when it has reached a universal consensus that this is the most valid description of a phenomenon. We say that we understand Newton’s Laws because it is well-tested and we know that it definitely work within a certainly range of condition. (…)
So in physics, the criteria to say that we understand something is very, very strict. It requires a well-verified theory that matches practically all of the empirical observations, and a general consensus among experts in the field that agree with it. This means that in many instances, physicists would tend to say that we don’t understand so-and-so, because there are many areas of physics that haven’t been fully answered, verified, or have reached a general consensus. To us, this does not allow us to say that we have understood it. But it certainly does not mean we know NOTHING about it. (…)
Do we understand QM? Damn right we do! Do we understand it COMPLETELY? Sure if what we mean by “completely” only includes things that we can test and measure. QM is THE most successful theory of the physical world that human has invented up to now and no experimental observation so far has contradicted it. So that alone is a very strong argument that we DO understand QM. However, if we ask if we understand how QM comes up with all the correct predictions of what nature does, or if there’s anything underlying all the QM’s predictions, then no, we don’t. (…)
I’ve been known to reply, whenever I get another question such as this, that we understand QM MORE than you understand your own family members. Why? I can use QM to make QUANTITATIVE predictions, not just qualitative ones, and make these predictions uncannily accurate. When was the last time you can do that with your family member consistently, day in, day out, a gazillion times a second? We use QM to do that and more.
artwork { Joseph Beuys }
