I am not sure if this makes sense. How would you build anything of some complexity? At some point you have to use components that are probably understood by som

I am not sure if this makes sense. How would you build anything of some complexity? At some point you have to use components that are probably understood by someone else but I don't think a single person can understood the whole system. How would you build a big rocket or an OS that way? EDIT: A good principle would be that every software author should understand his own code in detail. This is often not the case.