Cogito ergo sum. You may recognize this phrase as “I think, therefore I am.” While I won’t play philosopher here and examine Descartes’ words, I will discuss the importance of doubt and critical thinking in this letter.

Attacking a problem can be daunting. Whether in a classroom, a laboratory, or the “real world,” you often won’t find the solution on your first try. That’s okay. The more times you don’t get the “right” answer, the better your thinking can become. To paraphrase Descartes: “I learn, therefore I succeed.”

You have to question what went wrong, analyze the evidence, and draw a conclusion. This process develops critical thinking skills. Additionally, the experience can lead you to new results that are often more interesting than what you were originally trying to find.

I know because I had a seven-year version of such an experience, namely, my entire PhD.

In graduate school I wanted a thesis project involving quantum mechanics and high-power lasers. When I heard a talk about how quantum fluctuations might cause laser beams to break apart, I was hooked. The talk was on the theory—no one had observed the effect experimentally. I went to the professor who led that group and told him I wanted to be the one to do it.

For the next seven years, I tried. Along the way, I found many interesting results, published several papers, and ultimately wrote my thesis. However, I never observed the effect.

After I defended my thesis, my advisor told me he had never really expected the experiment to work, but he let me do it because he knew it would lead me down many new paths as I tried to overcome the challenges of the project. To him the outcome was as expected. It was not a failure, and I earned my PhD.

I learned much from that experience, most importantly that science isn’t the papers, it’s the process. Education should not be about simply learning facts, but rather about learning to think. Virtually any known fact can be found via your smartphone in a matter of seconds. Our goal (as humans and physicists) should be to look at the world around us, the problems we face, and be able to think critically and creatively to make things better.

So keep questioning, keep thinking, and don’t be discouraged when things don’t go as planned. As long as you learn from all that you do, you will never truly fail. //