Can Change Be a Contradiction?

Imagine you’re watching a video of a soccer ball rolling across a field. At exactly 3:00:00 PM, freeze the frame. Where is the ball? At one specific spot on the grass. Now unfreeze it, and a fraction of a second later it’s at a slightly different spot. That seems straightforward enough. The ball changed position over time. Nothing mysterious.

But here’s a weird question that won’t leave philosophers alone: What is the ball doing at the exact instant it’s changing?

At that frozen moment, is it moving or is it still? If it’s moving, it must be going somewhere—but a frozen instant doesn’t give it any time to go anywhere. If it’s still, then how does it ever start moving? This might sound like a silly puzzle you’d invent to annoy your math teacher, but it turns out to connect to some very deep questions about what change really is, and whether it might actually involve a contradiction.

The Problem of the Starting Car

Suppose a car sits motionless at a red light. At exactly noon, the light turns green and the car starts moving. What is the car doing at noon?

If you say it’s moving, then there must be some moment before noon when it started—but you just said it started at noon. If you say it’s motionless, then there’s a problem too: if it’s motionless at noon, when does it ever begin to move? Every moment after noon is a moment when it’s already moving, so there’s no moment where the change itself happens. The change seems to happen “between” moments, but there’s no “between” if time is made of instants.

You might think this is just a puzzle about how we define things. If the car’s speed is given by a nice mathematical function (like position = time²), then at noon its speed is zero—it’s not moving—but for every fraction of a second after noon, it’s moving. The car doesn’t need a “first instant” of motion; it just starts moving immediately after noon. Problem solved, right?

Not so fast. Philosopher Graham Priest argues that this “solution” actually shows something troubling. In this picture, there is no instant at which the car is changing. Every single instant is either a time when it’s still or a time when it’s moving. The changing itself never happens at a time. But change ought to happen at some time, or else what does it mean to say the car changes at all?

Two Ways to Think About Change

Philosophers have noticed that when something changes, it seems to have incompatible properties. Your younger self was short; your current self is tall. If they’re the same person (you), then you are both short and tall—which looks like a contradiction. The obvious way out is to say: “No, you were short then and you’re tall now.” The contradiction disappears because we add a time-stamp: short-at-age-8, tall-at-age-13. Different times, no conflict.

This is the most common view, and it’s called the cinematic view of change. It says change is just like a movie: a series of still frames (instants) where an object has one property at one frame and a different property at the next. There’s nothing mysterious happening at any single frame; the “change” is just the difference between frames.

The alternative view, championed by Priest and inspired by the philosopher Hegel, says that this misses something essential. When something is really changing, it’s not just that it’s different at different times. At the very moment of change, the thing is in between states—it is both what it was and what it is becoming. A moving arrow, at any instant, is both here and not-here. That sounds like a contradiction, and Priest thinks that’s exactly what change is: a genuine, real contradiction in the world.

Zeno’s Arrow Rides Again

You might have heard of Zeno’s paradoxes from ancient Greece. One of them goes like this: an arrow in flight is motionless at every instant (since at any single instant it’s only in one place). If it’s motionless at every instant, how does it ever move? The usual response is that motion isn’t something that happens at an instant—it’s something that happens across instants. The arrow’s velocity isn’t a property of a single moment; it’s a relationship between positions at different moments.

Priest thinks this response is unsatisfying. He puts it bluntly: “A sum of nothings, even infinitely many nothings, is nothing.” If at each individual instant the arrow isn’t moving at all, how does adding up a bunch of non-moving instants produce motion? Mathematicians have a way of handling this (using something called measure theory), but Priest says that’s just a mathematical trick—it doesn’t explain how the arrow actually achieves its motion. At any point in its journey, the arrow advances not at all. Yet somehow, over many points, it advances. That seems like magic.

For Priest, the only way to make sense of this is to say that at the instant of change, the arrow is moving—which means it’s both at its current position and not at its current position. That’s a contradiction, but it’s a real one.

The Buddhist Argument

Here’s another way to arrive at a similar puzzle. Suppose you have a person, let’s call her Maya. At age 8, Maya is 4 feet tall. At age 13, Maya is 5 feet tall. Now, there’s a logical principle called Leibniz’s Law: if two things are identical (the very same thing), then they must share all their properties. If 8-year-old Maya and 13-year-old Maya are the same person, then they must have all the same properties. But one is 4 feet tall and the other is 5 feet tall. Those are different properties. So they can’t be identical.

Something has to give. Either:

Maya at 8 and Maya at 13 are not the same person (they’re just connected in a way that feels like sameness), or
Being 4 feet tall and being 5 feet tall aren’t really incompatible (maybe height is relative to time), or
Change involves a real contradiction after all.

The Buddhist philosopher Dharmakirti (around the 7th century CE) chose option 1. He argued that nothing persists through time. What we call a “person” is really just a series of momentary stages, each one distinct. There is no enduring self that changes; there are only different selves at different times. This fits nicely with the Buddhist idea that everything is impermanent.

Modern philosopher Derek Parfit made a similar argument: what principle could possibly unite your 8-year-old self with your 13-year-old self closely enough to call them the same person? He concluded that none could, and that realizing we’re just sequences of stages might actually help us face death more calmly.

What About Our Experience?

Here’s where things get really interesting. Even if change could be described consistently (by saying that different time-slices have different properties), our experience of change might actually be contradictory.

Think about watching a moving dot on a screen. If you slow it down enough, you see it jump from position to position. But at normal speed, you don’t see jumps—you see a single dot moving. Your brain is doing something remarkable: it’s taking information from different times and treating them as one thing. The dot at time 1 is identified with the dot at time 2, even though they’re at different places. That identification creates a contradiction: the same thing is both here and there.

This isn’t just philosophical speculation. There’s a well-known phenomenon called the phi phenomenon (or apparent motion): if you flash two lights in slightly different positions at just the right interval, people see a single light moving between them. Your brain automatically constructs an enduring object where there are really just two separate flashes. The experience itself has a contradictory structure—the thing you see is both one thing (it moves) and not one thing (there are really two lights).

Some philosophers and cognitive scientists think that our perception of all motion works this way. The brain has a “now box” that briefly holds information from recent moments and compares them. The delay-and-compare mechanism (called a Reichardt detector) basically superimposes information from different times, treating them as if they belong to the same thing. This is a kind of contradiction built into our hardware.

A Halfway House

Not everyone goes as far as Priest. Some philosophers think that change only looks contradictory because of our limited perspective or the way our minds work. They argue that the world itself is perfectly consistent; it’s just that when we perceive motion, our brains create a contradictory representation. The contradiction is in our minds, not in reality.

Others think there might be special cases where real contradictions happen. For instance, in quantum mechanics, certain measurements seem to involve discontinuous changes that are hard to square with ordinary ideas about causation. Some philosophers have suggested that these quantum jumps might be genuinely inconsistent: a particle is both here and not-here, and that’s not just a limitation of our knowledge but a fact about reality.

So What’s the Answer?

Nobody really knows. Philosophers still argue about whether change is consistent or inconsistent, and the arguments on both sides are surprisingly strong.

What’s clear is that change is stranger than it seems. When you watch a ball roll across a field, or a friend smile, or a leaf fall from a tree, you’re watching something that has puzzled thinkers for over two thousand years. The obvious, commonsense view of change—things just, you know, change—turns out to be surprisingly hard to make sense of without running into contradictions.

Maybe that’s okay. Maybe the world is full of contradictions, and change is one of them. Or maybe we just haven’t found the right way to think about it yet. Either way, the next time you see something change, you might wonder: is this a contradiction happening right in front of me?

Appendix

Key Terms

Term	What it does in this debate
Cinematic view	The idea that change is just different properties at different times, like frames of a movie—no contradiction needed
Instant of change	The problematic moment when a thing is switching from one state to another, which seems hard to describe without contradiction
Leibniz’s Law	The principle that if two things are identical, they must share all the same properties—which creates a puzzle for identity through change
Phi phenomenon	A perceptual illusion where two separate flashes are seen as a single moving object—showing how the brain creates contradictory experiences
Reichardt detector	A mechanism in the brain (or a model of one) that compares information from different times by delaying one signal and superimposing it on another
Enduring vs. Perduring	Two ways to persist through time: enduring means the same thing exists at each moment; perduring means the thing is made of different temporal parts

Key People

Graham Priest – A contemporary philosopher who argues that change and motion are genuinely contradictory, not just apparently so
Hegel – An early 19th-century German philosopher who said motion is “existing contradiction itself,” and that things move because they contain their own opposites
Dharmakirti – A 7th-century Buddhist logician who argued that nothing persists through time; what we call a “person” is just a series of distinct momentary stages
Zeno of Elea – An ancient Greek philosopher who invented paradoxes (like the arrow) to show that motion and change are impossible if you think about them logically
Derek Parfit – A recent philosopher who argued that personal identity isn’t as solid as we think, and that we’re more like temporal sequences than enduring selves

Things to Think About

If change really is contradictory, what would that mean for science? Could a scientific theory contain contradictions and still be useful or true?
The phi phenomenon shows that our brains treat separate events as one thing. Are there other places where our experience might be systematically contradictory without us noticing?
If you’re not really the same person you were at age 8 (as Dharmakirti and Parfit suggest), should that change how you think about responsibility? Should you be punished for what “you” did years ago?
The “instant of change” problem seems like a puzzle about time. But what if time isn’t made of instants at all? What if it’s more like a continuous stretch where there are no exact points?

Where This Shows Up

Video games and animation: The cinematic view of change is literally how animation works—a series of still frames that create the illusion of motion
Quantum mechanics: Some interpretations of quantum physics involve particles being in multiple states at once, which looks a lot like the contradictory account of change
Your own experience: The phi phenomenon is why movies and TV work—your brain constructs continuous motion from discrete frames, and this creates a kind of contradiction in your perception
Artificial intelligence: Self-driving cars and robot vision systems have to solve the problem of tracking objects through time, and they run into versions of the same puzzles about identity and change