I applied to two PhD programs: the neurobiology department and the biological-chemistry department. What I really wanted to do was understand how synapses work; I wanted to be a neuroscientist. But I was not accepted by the neurobiology department. I was absolutely, flatly rejected. As a result, I could not work on synapses. Instead I worked in the biochemistry department and became a probably pretty decent biochemist, working on membranes.
Now the reason I mention all this is that it illustrates something, which is, I wanted to understand how a synapse worked. Had I been accepted as a neuroscientist, I would have probably worked on it. But I wouldn’t have solved it. The tools weren’t there. The time wasn’t right. Instead, I became a biochemist. I took on a much broader view of the same subject. And I ended up, somewhat by accident, solving the fundamental problem of how synapses work. Had I set out to solve that problem in a more direct way, I might not actually have gotten there first. It’s always good to know what you want to do, but be prepared for what comes. Luck plays a significant role. I went into cell biology wanting to be a neuroscientist, and I ended up a neuroscientist by accident.