Being, difference, and falsehood › A sentence can mean something and still be wrong

Imagine a consultant telling a client, "This system has passed the safety review." The system exists. The review exists. The sentence is easy to understand. But suppose the review has never been completed. The consultant has made a false assertion by joining familiar things in a way that misrepresents their relationship. Calling the sentence meaningless would miss what makes it dangerous: someone can understand it, believe it, and act on it.

This is a modern illustration of the difficulty Plato examines in the Sophist. How can a statement say what is not the case without becoming speech about nothing? The question sounds abstract until someone tries to use it to make error impossible. If every meaningful statement must concern what is, and falsehood concerns what is not, perhaps there cannot be meaningful false statements at all. A theory that reaches that conclusion needs to explain the ordinary mistakes it appears to eliminate.

Plato approaches the problem through a search for the sophist, a figure who appears knowledgeable without possessing the knowledge he displays. Defining that figure requires an account of appearances and deception. The search consequently becomes an inquiry into being, difference, and the structure of statements. Its useful lesson is precise: an assertion can fail because of what it says about its subject, even when its subject is perfectly real.