I think of a plot, I think of an idea, and then I wonder, How can I get that onto the stage? . . . Whatever devices you use should always be there to serve the theme. If the theme has been overtaken by the device, then something's wrong.
There is an idea abroad among moral people that they should make their neighbors good. One person I have to make good: Myself. But my duty to my neighbor is much more nearly expressed by saying that I have to make him happy if I may.
If we could travel into the past, it's mind-boggling what would be possible. For one thing, history would become an experimental science, which it certainly isn't today. The possible insights into our own past and nature and origins would be dazzling. For another, we would be facing the deep paradoxes of interfering with the scheme of causality that has led to our own time and ourselves. I have no idea whether it's possible, but it's certainly worth exploring.
We are the prisoners of ideas. They catch us up for moments into their heaven, and so fully engage us, that we take no thought forthe morrow, gaze like children, without an effort to make them our own.
When I get an idea I start at once building it up in my imagination. I change the construction, make improvements and operate the device in my mind. It is absolutely immaterial to me whether I run my turbine in my thought or test it in my shop. I even note if it is out of balance.