Those who believe in telekinetics, raise my hand.

The line is a compact joke built on self-reference and the logic of “testing” paranormal claims. If someone truly believes in telekinesis (moving objects with the mind), the speaker invites them to demonstrate it by raising the speaker’s hand—an action that would require telekinetic power rather than mere assent. The humor comes from the mismatch between belief and verifiable ability, and from the speaker’s sly refusal to participate in the usual way (raising his own hand). As a Vonnegut-attributed quip, it fits his broader satirical skepticism toward credulity and fashionable irrationalism, using a one-liner to puncture grand claims with a simple empirical challenge.