The hand moving the stick is an illustration, so don't get too caught up in the details. It's intended to explain what's meant by a series in which every member except the "first" merely passes along some causal power to the next member. The argument is that in such a series, the causal power in question must have a source, and therefore the series can't just extend infinitely backward (any more than you could see a face in the last of an infinite series of mirrors each reflecting the one before it).
But the source of the causal power needn't be, and ultimately isn't, merely the "first" member of the series. In the hand/stick illustration, the ultimate "First Cause," God, is outside the series altogether, endowing each element with being and causal power.
I prefer one of Ed's other illustrations: a musician playing a song on an instrument. When the musician stops playing, the instrument stops making musical sounds, and the song ceases. But in this series, the musician is the "first cause" in only a limited sense; his own existence and causal powers still need to be accounted for. That's where God comes in.
Last edited by Scott (11/01/2015 2:41 pm)