Fire is a chemical reaction. In a chemical reaction, molecules (themselves composed of a set of atoms) are rearranged in new molecules by creating and/or removing bound between atoms. Creating/removing these bounds will either release or absorb some amount of energy. When the reaction release energy, it is an exothermic reaction. When it absorb energy it is an endothermic reaction. Fire is the energy released by some exothermic reactions, in the form of heat and light.

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.

We decided to call what fire does to us “hot” and what ice does to us as “cold”. They are physically both different manifestations of the same thing, temperature.