Abstract: Philosophy is, for the most part, the study of what have turned out to be inconsistent concepts. An inconsistent concept is one whose constitutive principles are inconsistent with reality. The idea that most concepts studied by philosophers are inconsistent suggests conceptual engineering ought to be a central philosophical methodology. That is, philosophers ought to focus more on identifying defects in our concepts and improving our conceptual schemes. I focus on explaining these central claims, exploring some examples, and replying to a few objections. In particular, I consider the “omnicide” objection, which states that conceptual engineering for one single concept or word causes, as a side effect, changes in all the rest.