In classical philosophy, examples such as water becoming air, or air becoming water, served to illustrate a change of specific form. The proposed explanation was that different forms might successively inform a common underlying substrate.
This is a historical philosophical model, not a statement of modern experimental physics. Modern accounts of states and chemical composition use different explanatory frameworks.
The relevant logical lesson remains: observing change is one claim; asserting that the proposed underlying substrate is beginningless is another. The first alone does not establish the second.