Every occurrence is the result of prior events, and is a contributing cause of future events.
The easiest way to view this concept, is to consider the universe as flowing through time, rather than as a static conglomeration. Every electron within every atom of the stone has changed position. Some mass has been converted to energy, the surface has altered in reaction to the atmosphere, and all the components of the stone are further along in their change into another form. Nothing about that stone is exactly the same as it was a moment ago. All of this applies to humans, with the addition of elements that pertain to living things.