Philosophy trips us up by asking us to look for the common factor shared by two uses of the same word. Wittgenstein introduces another idea that will become more central in his later thought: when one catch-all definition falls short, we are tempted to refine this definition rather than take a step back and ask whether such a definition can be found. Wittgenstein will later characterize the complexities of modern philosophy as the result of increased refinements of ideas that were misguided from the outset.