1. Change occurs (objects and states are being actualized, or made real)
2. Whatever is being actualized is being actualized by something already actual (i.e., existent, real)
3. Either there is a transmitter of actuality, or nothing is being actualized
4. Therefore, there is a transmitter of actuality
The transmitter of actuality cannot be being actualized by something else, because then it would just be yet another receiver of actuality and hence not the transmitter/source of actuality. So there is, in other words, an UNactualized actualizer.