There is another way I have found to divide the processes. Growth, digestion, and crime all have the property that they occur in chains: in the growth of a human being from a cell, the transformation of a meal in the body, or the development of a cancer, we can trace link after link, each following on naturally from the preceding one, the last term of one triad becoming the first term of the next, and changing its function accordingly. We may call these processes `open'.
On the other hand, there is no chain of reduction: the product of reduction usually becomes the starting point for a different chain of digestion. Nor is there a chain of invention: the goal of this process is always a single, definite transmutation. And work, being a process of self-overcoming, can never be self-perpetuating. These three processes ---reduction, invention, and work---we may call `closed'.