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

The sentence expresses a broadly Kantian concern—philosophy must unite empirical content (experience) with guiding concepts or principles (theory). Read in that light, it warns against two one-sided approaches: raw experience unguided by concepts cannot yield clear knowledge (“blind”), while abstract theorizing detached from what is given in experience becomes empty or merely speculative “play.” Although the wording here is not securely traceable to Kant, the underlying idea parallels his critical project of explaining how experience and a priori concepts cooperate in cognition, and it also resembles later formulations about the mutual dependence of practice and theory.