The error was essential?

Does " the error was essential" mean "the error was absolutely necessary"?

Context:

The role of failure[http://en.wikipedia.org/w/index.php?title=Freeman_Dyson&action=edit§ion=20]

You can't possibly get a good technology going without an enormous number of failures. It's a universal rule. If you look at http://en.wikipedia.org/wiki/Bicycles, there were thousands of weird models built and tried before they found the one that really worked. You could never design a bicycle theoretically. Even now, after we've been building them for 100 years, it's very difficult to understand just why a bicycle works – it's even difficult to formulate it as a mathematical problem. But just by trial and error, we found out how to do it, and the error was essential.^{http://en.wikipedia.org/wiki/Freeman_Dyson#cite_note-BrandInterview-56}