We're told that nothing lasts forever, but we don't want to believe it. We want to believe that some things transcend time. We want to believe that some things beat the odds, that some things will remain a constant. We do this so we can have a reference point in our minds and our hearts. While the confusing world rushes past us day by day, while situations and people change like the autumn leaves on a tree, while our image in the mirror quickly distorts with age, we hold on to our secret reference point. We hold on to that "one" thing, even if we don't know what that one thing is, because if we don't hold on to it, we have to face that all of the created world is just an ever-flowing river of energy with no constants, no shores, no beginning, and no end. And that frightens us more than anything else.
But nature never lies. You can see that this solid rock has begun the process of not being a solid rock after all. It cracks, erodes, and slowly becomes the soft plant life around it. Who knew the moss could be so hard? Nothing lasts forever, of that you can be sure. Perhaps that in itself can be the "one" thing.