The success of the scaling-up process depends upon the fact that the conceptual integrity of each piece has been radically improved--that the number of minds determining the design has been divided by seven. So it is possible to put 200 people on a problem and face the problem of coordinating only 20 minds, those of the surgeons. For that coordination problem, however, separate techniques must be used, and these are discussed in succeeding chapters. Let it suffice here to say that the entire system also must have conceptual integrity, and that requires a system architect to design it all, from the top down. To make that job manageable, a sharp distinction must be made between architecture and implementation, and the system architect must confine himself scrupulously to architecture.