Imagine a rock has become dislodged, rolling down a hill just on the outskirts of town. As it's rolling, it picks up an amount of money, which sticks to it. The rock has just enough momentum to roll into a pie shop. The money falls on the counter, a pie is given to the rock, along with the change, and the rock and the pie are then carried out by another customer and placed on a bench.
Did that rock just buy a pie!?