When I taught physics I found that that most students approached the subject with the belief that the concepts would be simple to master, but that they would have to struggle with the mathematics. It turned out that the reverse was nearer to the truth. Although the mathematical language of physics does take time and effort to learn, (and the beginner has to learn to use equations as part of his thinking -- which takes practice) the concepts are often harder to master at every level. A student who can use the concepts of momentum and energy to solve simple mechanics problems, for example, has already learned to think like a physicist and will often impress his teachers, even though he may know only rudimentary mathematics. I found that coming to terms with the basic concepts underlying quantum mechanics took me more than a decade, while deeper conceptual issues remain unresolved for me even now. Learning the mathematical framework, while taxing, was not nearly as difficult.

With this observation in mind, as a neophyte in economics, I worked especially hard to understand the division of labor and its consequences. The results surprised me. I was especially surprised at how difficult it is to get one's mind around all of the contributions to and consequences of the division of labor and to come to grips with this elusive concept.

The difficulty has its roots in the nature of science. The problem is described in a section titled "The Method of Elementary Abstraction" in Chapter 1 of Lindsay and Margenau's book *Foundations of Physics *(first published in the nineteen thirties, reprinted in 1981)*.* These two philosophers of science noted that the physical world is immensely complicated, so that when we attempt to isolate the fundamentals -- a central part of the scientific enterprise -- we may find the task to be challenging. This difficulty is much worse in economics and the division of labor presents special problems. The division of labor is what makes economics complicated and messy, but its effects are essential and universal, and therefore difficult to isolate so that we can see them clearly.

Nailing down a concept such as the division of labor precisely may involve tediously going over old ideas. It can be very pedantic. But sometimes this pedantry is essential if mistakes are to be avoided. For example, I suspect that the effects of the division of labor have often been incorrectly attributed to some kind of economic "friction" -- a serious conceptual error that is explored in several of the posts below.