This philosophical movement of sophists was based on the view that there is a profusion of "truths" - perhaps as many as there are people to believe them - but no single, final Truth, and that language makes its own reality.
Through the Nominalism idea, an argument, however firmly it seems to stand up, however watertight its logic, can always be demolished by contrary argument, if made by a skilled debater. - Man is the measure of all things.
Every angle can supported in some way by infinite interpretations. Therefore falsehood and truth parish.
What about someone who believes in beautiful things, but doesn't believe in the beautiful itself…? Don't you think he is living in a dream rather than a wakened state? (Republic 476c)