There are two kinds of failures: those who thought and never did, and those who did and never thought.

The aphorism divides “failure” into two complementary errors: paralysis by analysis (thinking without acting) and impulsive action without reflection (doing without thinking). By framing both as failures, it rejects the comforting idea that caution alone is virtuous or that energetic activity alone is sufficient. The implied ideal is a balance—thought that leads to action, and action informed by thought—suggesting that effective living and work require iterative movement between planning and execution. Attributed to Laurence J. Peter, it aligns with his broader satirical interest in organizational and personal incompetence: people and institutions often err by over-deliberating or by charging ahead blindly.