If you want to understand the universe, you can't just look at what's there. You have to imagine what isn't, but was. This is a picture of an arch. It's a marvel of primitive architecture. In fact, the similarity of those two words is not a coincidence. All of those stones are slightly wedge-shaped, and when they are put together like that, gravity alone holds them in place. And the more you load them from above, the more firmly wedged together they become. But... how do you build it? It isn't stable until the last stone is in place. If you try to add one stone at a time, they'll just fall down. And it's not like you have as many hands as stones. If you look at an arch, and see only what is there, it looks like it can't be built. So you have to look at it and see what is no longer there. You need to see, in your imagination, the support that held the stones in place, and was taken away when it was no longer needed. In the simplest form, it could be just a pile of rocks in the shape of that doorway. When I wrote my first novel, tens of thousands of words flowed out of my keyboard which never made it onto the pages of what I published. And you can read it and say, "how brilliant!" "Look at all these wonderful ideas, and how they fit together, like stones in an arch!" But it's easy to look brilliant, as an author. You can make mistake after mistake, throw them all away, keep the good ideas that came in between the mistakes, and release a version that is every good idea you had in a year, with all the mistakes missing. Then someone reads it in two days. The point here is, if you see an achievement, any achievement, which seems so genius, or so far-fetched, or so complicated, that you can't imagine how someone came up with it all at once, the answer is probably that he didn't. It emerged step by step, with intermediate forms, or scaffolding that's no longer there, or a lot of mistakes that now lie on the cutting room floor. ...