 It is important to emphasize that Carnap’s Principle of Tolerance introduces a new conception of philosophy with far-ranging implications beyond those just discussed concerning verification. The idea that philosophy is concerned with language and its analysis was not new. What is novel is the idea that what had been seen as philosophical claims were better understood as proposals for structuring the language of science. Since these languages and the concepts they contained were to be thought of as tools, none of which was uniquely correct, the choice among the alternatives was a practical decision about usefulness for certain purposes rather than a theoretical question. Philosophy still has important work to do: It can analyze existing concepts. And since many existing concepts are vague, it can also make them more precise in a variety of ways through explication. Philosophy can also investigate wholly new concepts. In all this, philosophy explores the consequences of structuring the language of science in this way or that. It becomes, thus, a kind of conceptual engineering. Conceptual analysis, explication, construction, and engineering continue to be fruitful ideas in philosophy, though it is not always understood how much of this was initiated or shaped by Carnap and other logical empiricists.