My approach to what I do in my job — and it might even be the approach to my life — is that everything I do is the most important thing I do. Whether it’s a play or the next film. It is the most important thing. I know it’s not going to be the most important thing, and it might not be close to being the best, but I have to make it the most important thing. That means I will be ambitious with my job and not with my career. That’s a very big difference, because if I’m ambitious with my career, everything I do now is just stepping-stones leading to something — a goal I might never reach, and so everything will be disappointing. But if I make everything important, then eventually it will become a career. Big or small, we don’t know. But at least everything was important.
A theory of change is the opposite of a theory of action — it works backwards from the goal, in concrete steps, to figure out what you can do to achieve it. To develop a theory of change, you need to start at the end and repeatedly ask yourself, “Concretely, how does one achieve that?”
These days I am more interested in the reverse case [of Da Vinci's helicopter]: ideas that could have worked many centuries before they actually appeared. The economist Alex Tabarrok calls these “ideas behind their time”
Curious minds want to know why these ideas appeared so late — and whether there might be anything that would prevent delays in future. One explanation is that the ideas aren’t as simple as they appear.
The bicycle is not as straightforward an invention as it seems. To move from ox-hauled cart to human-powered bicycle requires smooth-rolling wheel bearings, which in turn need precisely engineered bearing balls. Modern steel ball bearings were not patented until the late 1700s, and demand from the 19th-century bicycle industry helped to improve their design.