The moon is at its highest point in the sky. Sirens sit on rocks by the sea, fluting and singing. Thales and Homunculus arrive at the shore, the philosopher urging the creature to speak with the prophetic sea-god Nereus. Homunculus decides to take a chance, and he knocks at the door of Nereus’ cave. Nereus is enraged to hear human voices, for people seek to be gods but never heed his godly advice. He moves away toward the sea to be with his daughters, the nymphs, advising Homunculus to speak with the powerful shape-shifter Proteus instead about changing his form and achieving a real existence.
Homunculus is seeking at the Aegean Sea nothing less than life. He wants to be transformed from his unnatural state into a natural one. The sea is an appropriate place to do this, of course, because it is the origin of life itself. Nereus recommends Homunculus speak to Proteus because Proteus is a master of shifting his shape, and this is exactly what Homunculus is looking to do. Proteus represents the power and diversity of life.
Homunculus and Thales withdraw to speak with Proteus. They lure him over to them by shining the lamp of Homunculus’s vial. The tricky shape-shifter comes in the form of a giant turtle and then, at Thales’ request, transforms into a stately human figure. Proteus advises Homunculus to achieve his real existence by going out into the open sea, where life began.
Like Chiron, Proteus integrates the animal and the human, the intellectual and the sensual. The devil earlier told Homunculus that he can only learn from his own mistakes, but because he is an unnatural creature, Homunculus must rely on nature outside of himself for his education in existence.
Proteus transforms into a dolphin, on whose back Homunculus rides to the open waters. There his lamp illuminates the grace and beauty in the waters. From afar Thales sees Homunculus’ flame burn brighter with passion, till at last Homunculus shatters his vial and his fiery being embraces the waves. Everyone praises the elements.
Homunculus goes out into the sea, where he learns the laws of nature to which he must accommodate himself if he is to really live. He lovingly surrenders his unnatural body to the natural waters, becoming one with the whole of nature. This scene foreshadows Faust’s ascension into heaven at the end of the play.