Change

Change is the transition of a thing from one state to another. A leaf turns from green to brown. A task moves from pending to complete. A river shifts its course. For something to be changing, something must change—and for change to be real, something else must remain the same.

¶Four Types of Change

Aristotle’s Physics (Book III) distinguishes four types of change (metabole), and the distinction still holds. Not all changes are alike.

Generation and corruption are the most radical: coming to be and ceasing to be. When a thing begins to exist or ceases to exist, it has generated or corrupted. A table does not exist, then a carpenter acts, and the table is. The wood has become a table. This is generation of the table and corruption of the wood-as-mere-wood; the substance (wood) persists but the form changes. When a house is torn down, corruption occurs; the wooden beams persist but the house ceases to be.

Alteration is a change in quality while the thing persists. A cloth turns from white to blue. A room grows warm. A person changes from well to sick. The substance stays: it is still cloth, still a room, still a person. What changes is a quality.

Growth and diminution are changes in quantity. A child grows taller. A tree gains girth. A pile loses stones. Again, the thing persists—still a child, still a tree, still a pile—but its size changes.

Locomotion is change of place. A car moves from the parking lot to the street. A bird flies from tree to ground. The thing persists in all its qualities; it is in a new location.

These are not one phenomenon with four names. They have different ontological status. Generation addresses whether a thing exists at all. Alteration addresses its qualities. Growth addresses its extent. Locomotion addresses its position. Understanding which type of change is happening is essential to understanding what is happening.

¶Persistence Through Change

Change requires persistence. For something to change, it must be something that changes. If a caterpillar becomes a butterfly, there must be something—call it the organism—that persists through the transformation. Otherwise it is not change but replacement. One thing ceases, another begins.

This is why Aristotle grounds change in substance. The substance is what persists. When the substance loses one quality and gains another, that is alteration. When the substance moves, that is locomotion. The substance is the constant through which change occurs.

But what counts as substance? A river changes course but remains a river. The water molecules flow through, but the river persists. The river’s identity is in the flowing pattern, not in any particular water molecule. Similarly, a person persists through hair loss, weight gain, and all manner of alteration. The cells of the body are replaced entirely over seven years, yet the person remains.

This suggests that persistence is not about material identity but about continuity of form and pattern. What persists is not a stuff but a structure. The river persists as the valley shape and the flow pattern. The person persists as the body’s organization and the continuity of consciousness and character.

¶Process and Becoming

Heraclitus said you cannot step in the same river twice. This is not because the water is different—it is because both you and the river have changed. Heraclitus goes deeper: the river IS flowing. To be a river is to flow. Change is not secondary to the river’s existence; it is what makes the river a river. If you stopped the water, you would have water in a valley, not a river.

Bergson (Creative Evolution, 1907) argues that change is more fundamental than states. What we call “states”—the river as it is now, the color as it appears to be now—are artificial snapshots we take of continuous becoming. Real time is durée, duration, the interpenetration of moments. The past is not gone; it lives in the present, shaping what comes next. The future is genuinely open.

On this view, there are no unchanging states. There is only change. What we perceive as a “state” is a threshold or grain in the flux—a level at which we conventionally divide the continuous change into discrete moments. But the continuity is more real than the divisions.

Whitehead (Process and Reality, 1929) makes becoming itself the ultimate unit of reality. An actual occasion is an act of becoming. When it completes its becoming, it perishes—not in the sense of being annihilated, but in the sense of achieving its full actuality. It becomes data for the next occasion. The perishing is not loss; it is the occasion achieving its completeness. Persistence emerges from the continuous succession of occasions, each prehending (taking into account) the occasions that came before.

On this view, a “thing” is not a substance that endures unchanged through time. A thing is a vessel—a society of occasions, a pattern that persists through repeated succession. The thing persists because the pattern continues, not because any substance remains identical.

¶What Drives Change

Deleuze (Difference and Repetition, 1968) distinguishes intensive and extensive properties. An extensive property is one that can be divided: length, weight, number. An intensive property cannot be divided without changing: temperature, pressure, potential. A difference in temperature drives change. When there is a temperature difference, heat flows from hot to cold. The intensive difference is the engine; the resulting extensive rearrangement (new temperature distribution) is the product.

This is why Deleuze says intensive differences are more fundamental than extensive states. Change is not a transition from one state to another. Change is the resolution of tensions and gradients in the situation. Before a new temperature distribution settles, the situation is one of intensity—tension, difference, gradient. The temperature difference creates pressure (in the literal sense) toward equilibrium. Heat flows until the gradient is resolved. The resulting uniform temperature is the stabilized extensive product.

This applies beyond physics. A difference in knowledge creates intellectual tension—curiosity, confusion, the drive to resolve the difference. A social difference creates pressure toward either accommodation or conflict. The intensive difference is what makes change real and directs it. The extensive change is the result: the new knowledge acquired, the social structure altered.

¶What Change Is Not

Change is not mere motion. A wheel spinning in place is moving, but if it returns to its original position and state, it has not changed. Motion is change of place. Change is broader: it includes alteration of quality, growth or diminution, even coming to be and ceasing to be.

Change is not an illusion. Some philosophers have argued that true reality is unchanging and that change is mere appearance—a confusion caused by our limited perception. But this contradicts what we observe. Seeds become plants. People age. Civilizations rise and fall. To call all this appearance is to deny what is most manifest. Change is real.

Change is not random. Aristotle grounds change in actuality of potentiality—the realization of what is possible but not yet real. The wood has the potential to be a table; the carpenter actualizes that potential. The change is directed by what the thing can become. Bergson grounds change in creative advance—the genuine emergence of novelty constrained by what came before and what the system can sustain. The change is neither predetermined nor arbitrary; it is the creative development of possibility into actuality.