Experience without theory is blind, but theory without experience is mere intellectual play. – Kant Quote

Kant’s treatment of the transcendental logic in the First Critique contains a portion, of which this quote may be an ambiguously worded paraphrase. Kant, claiming that both reason and the senses are essential to the formation of our understanding of the world, writes: “Without sensibility no object would be given to us, and without understanding none would be thought. Thoughts without content are empty, intuitions without concepts are blind”.

Related Quotes
“Experience arises together with theoretical assumptions not before them, and an experience without theory is just as incomprehensible as is (allegedly) a theory without experience.”
Paul Karl Feyerabend, Against Method pg 151. Against Method (1975)

“Experience by itself teaches nothing…Without theory, experience has no meaning. Without theory, one has no questions to ask. Hence without theory there is no learning.”
W. Edwards Deming, The New Economics for Industry, Government, Education (1993)