The math of quantum physics allows us to do engineering, like in designing computers. That’s very valuable. But what if people want to understand the universe that they live in? What if they are trying to form a concept of how its fundamentals work? Most people aren’t going to be able to picture the workings of the universe by looking at equations.

One of the most compelling reasons that people become scientists is that they are curious about how things really work. For this reason, they look at the equations and come up with explanations (interpretations) as to how the equations describe nature. So, the first reason for the various interpretations is the reason that scientists do science to begin with — they are led by their curiosity to increase their understanding of how the universe works—how its forces and principles interact.

Beyond fulfilling curiosity, there is another usefulness to interpretations: they allow expansion of the theory, which can lead to practical applications — like engineering. For example, let’s say that quantum physicists did no more than write equations in physics papers. Well, the quantum behavior of photons in photosynthesis might never have become a developing part of botany. What botanist would sit around poring through equations in a physics journal? But because physicists have tried to explain quantum physics conceptually in popular articles, usually via the Copenhagen Interpretation, botanists were alerted to a possible explanation for the mysterious workings of photosynthesis.

The theorized quantum behavior of photons in photosynthesis might turn out to very important; photosynthesis is a fundamental biochemical reaction that feeds us. And, who knows—understanding a potential quantum aspect of photosynthesis might lead to more efficient solar panels.

Interpretations of equations are needed throughout physics because we are human beings, not robots. If we were robots, we could just program ourselves with equations and shush ourselves with, “Shut up and calculate.” But we are human beings who like to turn things over in our minds, relate one scientific principle to another, and make progress by deepening our understanding of the universe.

For a bit more about quantum behavior and photosynthesis, see the end of this article about the Copenhagen Interpretation of quantum physics.