Fire is not fire. Therefore fire is not hot.

The distinction is between a thing in relation to other things and for us and a thing in itself. To the extent that water cannot wet, it is not water. To the extent that fire cannot burn, it is not fire. Yet precisely for not burning itself, fire is fire; and for not wetting itself, water is water. X is not X, therefore it is X. For precisely in its act of burning firewood, fire does not burn itself; and in not burning itself, it burns firewood. It burns in relation to something else, but in-itself (in relation to itself) it does not burn.

The burning that takes place when the fire burns firewood points to the selfness of fire, but so does the fact that fire does not burn itself. The two are here one and the same. As something that burns firewood, fire does not burn itself; as something that does not burn itself, it burns firewood. This is the mode of being of fire as fire, the self-identity of fire. Only where it does not burn itself is fire truly on its own home-ground. In other words, we speak not only of the selfness of fire for us, but also of the selfness of fire for itself … That a fire sustains itself while it is in the act of burning means precisely that it does not burn itself. Combustion has its ground in non-combustion. Because of non-combustion, combustion is combustion. The non-self-nature of fire is its home-ground of being.

https://buddhism-thewayofemptiness.blog.nomagic.uk/the-logic-of-soku-fire-is-not-fire-therefore-it-is-fire/