An argument in classical geometry constructs a circle by keeping one endpoint of a line fixed while rotating the other. The moving end traces the circumference, and the fixed end is treated as the center.
This construction explains a geometric relation, but the metaphysical question remains: does that construction and the continuity of the motion prove the existence of indivisible material substances in the body?
Critical distinction: a center, circumference and rotating radius can be defined within a geometrical model. Inferring the presence or absence of ultimate physical atoms requires an additional and justified argument.