dhūmād vāpi sva-sambhavāt
yathāgniḥ pṛthag ulmukāt
Although the blazing firewood, the sparks, the smoke and the flame cannot stay apart because each of them is part and parcel of the fire, still they are different from one another. A less intelligent person accepts the smoke as fire, although fire and smoke are completely different. The heat and light of the fire are separate, although one cannot differentiate fire from heat and light.