The barnyard rooster Chanticleer had a theory. He crowed every morning, putting forth all his energy, flapped his wings. The sun came up.

The connexion was clear: His crowing caused the sun to come up; there was no question about his importance. There came a snag. He forgot one morning to crow. The sun came up anyhow. Crestfallen, he saw his theory in need of revision.
Without his theory, he would have had nothing to revise, nothing to learn.

It is extension of application that discloses inadequacy of a theory, and need for revision, or even new theory. Again, without theory, there is nothing to revise. Without theory, one has no questions to ask. Hence without theory, there is no learning.

Theory is a window into the world. Theory leads to prediction. Without prediction, experience and examples teach nothing. To copy an example of success, without understanding it with the aid of theory, may lead to disaster.

Any rational plan, however simple, is prediction concerning conditions, behavior, performance of people, procedures, equipment, or materials… A statement devoid of rational prediction does not convey knowledge.

No number of examples establishes a theory, yet a single unexplained failure of a theory requires modification or even abandonment of the theory.

Deming WE 1994 ‘The New Economics: For Industry, Government, Education’ MIT Press: Massachusetts pp102-3