In a traditional academic model, the time allotted to learn something is fixed while the comprehension of the concept is variable. Washburne was advocating the opposite. What should be fixed is a high level of comprehension and what should be variable is the amount of time students have to understand a concept.
In gradually developing my own approach to teaching, one of my central objectives was to reverse this balkanizing tendency. In my view, no subject is ever finished. No concept is sealed off from other concepts. Knowledge is continuous; ideas flow.