You live your life the way a film projector turns separate frames into movement.
Immanuel Kant is saying that everything we experience appears in time. We experience events as happening one after another or at the same time. But time itself is not something we can directly see or touch. We never perceive “time itself” floating independently. We only perceive changing things. So if we are able to notice succession, continuity, and change, there must be something within experience that stays stable enough to function as a reference point. Otherwise experience would dissolve into disconnected fragments. Imagine trying to notice movement on a screen if the entire screen, memory, and perspective all changed completely every instant. You would not perceive movement. You would only have unrelated flashes.
Kant therefore says that in experience there must be some persistent background that allows change to be organized in time. He calls this persistent element “substance” that does not mean here a mystical hidden material. It means whatever remains sufficiently stable so changes can be recognized as changes of something. For example, when you watch a tree through the seasons, the leaves change, colors shift, branches grow, parts decay. Yet you still experience “the same tree” undergoing changes. The persistent object allows time-relations to make sense.
Kant's argument goes like this: we can't directly see time itself, but we can notice changes happening around us. To understand these changes, we need something stable to compare them to. This means that our experiences are shaped by a constant background that helps us make sense of what we see. Kant refers to this constant background as substance.
Then he adds another claim. Since substance is the underlying continuity that makes temporal experience possible, it cannot simply appear or disappear arbitrarily within experience. Its total quantity in nature remains constant. Things transform, rearrange, dissolve, and recombine, but nature does not suddenly gain or lose underlying reality itself. In modern terms, this resembles conservation principles in physics. Matter and energy change forms, but are not simply created from nothing or erased into nothing within ordinary natural processes.
But Kant’s main point is transcendental, not scientific. He is asking what conditions must already exist for coherent experience to happen at all. The point about duality fits here very well. Kant is effectively describing cognition as requiring stable relations within flux. The mind needs both difference and persistence. Difference alone gives chaos. Persistence alone gives frozen sameness. Experience emerges from stable patterns changing over time.
So the human world is neither pure permanence nor pure flow. It is organized continuity. The organism stitches succession into identity the way a film projector turns separate frames into movement. Without the stitching, there is no world. Only flashes no one could survive inside.