A good reference for this hierarchy is in the works of Russell Ackof. He
explains the difference between each one of those and their implications
for learning. He claims that most management education and practices are
at the level of knowledge or you know what to do but do not know Why you
are doing it. He claims that systems thinking takes you to the
Understanding level, where you know the why of what you are doing.
-- Manuel Manga <email@example.com>