How exactly is change the only constant in the world?

It is sometimes said that the only constant in this world is change. But the meanings of those very words do not change so quickly—or at least, they change very slowly.

For example, we eat food with our hands. That basic action hasn’t changed. The food goes into our body through our mouth—that also hasn’t changed.

This brings to mind a foundational verse of the Bhagavad-gita (2.16):
“Na sato vidyate bhavo na bhavo vidyate satah”
—”Of the non-existent (temporary), there is no endurance. Of the eternal, there is no cessation.”

This truth may be phrased differently at different times. Some phrasings may be more rhetorical than literal. So, when we hear statements like “everything is constantly changing,” do we take them literally? Not exactly—it’s more of a rhetorical truth than a literal one. After all, for someone to perceive change, some part of the observer must remain unchanged. Without a relatively stable observer, how could we even register change?

Now, do things in the material world change? Yes, certainly. But does everything change at every moment? Not necessarily—different things change at different paces.

Take eating, for instance. We generally eat food with our hands. But that’s not universal. When we’re infants, others feed us. In old age or during illness, we might be fed through tubes or intravenously. So even basic actions like eating change over the course of a lifetime.

If the soul enters a tree body, it absorbs nourishment not through a mouth or hands, but through its roots. If we were to apply human anatomical assumptions to trees, we’d say they “eat” through their legs. This shows how even what seems unchanging can change depending on perspective.

Even when we say, “I’m eating with the same hand, using the same mouth,” biologically, that’s not entirely true. The cells in our hands and mouths are constantly dying and regenerating. At the cellular level, change is ongoing.

Going deeper, the Bhagavatam compares the material world to a movie. To us, it appears as a smooth, continuous experience. But in reality, a movie is a series of still images projected rapidly, creating the illusion of seamless motion. Similarly, the material world may appear to change gradually, but in many ways, it’s a rapid succession of changes, one frame replacing another.

Some philosophical perspectives even describe the material world itself as operating this way—like frames flickering across the screen of time. Of course, no metaphor can fully capture the nature of material existence, so this too must be taken with qualification.

Still, the broader principle remains: change is universal. And to the extent that we accept this truth, we can free ourselves from being overly attached to the changing nature of this world. We become less fixated, less dependent on material stability, and more grounded in the eternal.

Yes, things keep changing. The pace of change may differ. The nature of change may differ. But change itself is constant in the material world.