Dr. Jones, however, divides his time among a variety of occupations. Along with performing neurosurgery, he practices dentistry, gynecology, podiatry, and radiology. He also spends part of each day teaching political science at the local college, and another part of each day as an investment counselor. If your brain tumor hasn't yet seriously diminished your capacity for rational thought, you'll choose Dr. Smith the specialist. Dr. Jones might well be more brilliant than Dr. Smith, but common sense correctly tells you that even the world's smartest person can never master a complex task if that person spreads himself too thin.
Mastery requires specialization.
In our everyday lives, we all grasp this fundamental truth about the importance of specialization. Each of us is trained through schooling, experience, or both to do a particular job. None of us grows his own food, weaves his own cloth, brews his own beer, mixes his own toothpaste, and works as a CPA or a pipefitter. In fact, none of us even thinks to try to do all these things. Nor do we purchase goods and services from non-specialists with one big exception.