The goal of science, as we all know, is to discover simplicity in the midst of complexity. Yet when Paul Nurse, Tim Hunt and I and our students and colleagues began studying how cells divide, any sensible scientist should have expected to find only hopeless complexity. If you think of cell division as a symphony, we knew that the symphony had to be performed by thousands of musicians each playing a different instrument. So - our research can only be described as motivated by a kind of foolish optimist. Sometimes nature rewards foolish optimism. Continuing with the metaphor of cell division as a symphony, our research paths led each of us, independently and by great luck, smack into the conductor of the symphony. And, it turned out that the same conductor performed this symphony in all types of cells - yeast, fruit flies, sea urchins, frogs and humans. I really have no idea how often nature rewards such foolish optimism, but I am pleased to report that the Nobel committee is rather fond of foolish optimism.
That is Leland H. Hartwell's speech in 2001. He is a Nobel Laureate in psychology or medicine. Source.