Life, just simply is. Nor is there evidence to explain the other big abstract, love. Neither scientist nor philosopher has any clue as to why love exists, yet I, who has been more often than not been called a madman with a pen, has the answer. One cannot exist without the other. A symbiotic relationship.
Heat therefore exists.
Cold, however, does not. It is the absence of heat, as surely as darkness is the absence of light. The sun goes down at night and the Earth cools because there is no sun. We all know hate exists. It surrounds us.