Orders of Ignorance

In reading some of Phillip G. Armour's Orders of Ignorance, I had a couple of thoughts. He describes in the beginning the process of development as an acquiring of knowledge. He also states that unknowledge gained is not necessarily unimportant; he quotes Edison as saying something along the lines of, and I paraphrase, "Mistakes show us how not to do something, which is just as important." I think this is a very important point, and it leads to one of my main thoughts. One of Armour's questions that he raises multiple times is, if we've done something before, why are we doing it again? An answer I propose is what is known as a pattern in software, where we are required to do something very similar, but not the same, as what we've done before. If we've made mistakes before, we already know how not to build the new product, and by process of elimination, we know what will probably work. This cuts our development time drastically.