For from the potentially existing the actually existing is always produced by an actually existing thing, e.g. man from man, musician by musician; there is always a first mover, and the mover already exists actually.
25) adibidez, gizaki bat beste gizaki batengandik sortzen da, eta musikari bat beste musikari batek sortua da, mugiarazle bat izanik beti, mugiarazlea dagoeneko egintzan delarik.