Chris Argyris (1923 – 2013) clarified that there are two levels to learning, which he described as single-loop learning and double-loop learning.
Here are his definitions:
In the Agile space, you can think of “Inspect and Adapt” as single-loop learning in order to improve the process you are doing. For example, a sprint retrospective would have you look at how you could improve the what you did in the last sprint. Double-loop learning, would have you look at whether you should even be doing sprints. In other words, single loop learning is questioning how to do your process better while double loop learning questions the assumptions on which your process is based.
Here are a few excellent articles on double loop learning: