How is the existence of other people proof of signalling theory? I believe you exist. Signalling theory could, for example, say I am holding up this argument

How is the existence of other people proof of signalling theory? I believe you exist. Signalling theory could, for example, say I am holding up this argument on the internet because I want to show others how persistent I am. How does your existence prove or disprove why I am saying what I am saying?