We know how to train the brain of a human being to learn physics (well not always), but that doesn't means that we understand how that brain really works. The

We know how to train the brain of a human being to learn physics (well not always), but that doesn't means that we understand how that brain really works. The life if full of examples of things we know how to use but that we don't understand. Sometimes it's just impossible to control that things. Think in the stock market or economics. Chemist has been studying this type of things for centuries and you can see the result: there are chemical products everywhere you look. What the post attack is the concept of creating nanomachines that doesn't degrade (Cosmic rays! oxidation! temperature!!) and do exactly what we want. And about the "artificial DNA", it's something so simple... Really! the problem is in the emergent properties of DNA, proteins and environmental effects, this is where you loose control. Even nature has problems with that, life forms die, had cancer...