“There are, however, many ways to look at the evolution of mankind. Rescher stresses that, after all, intelligence has evolved not because it aids the survival of its possessors within nature. It arose because it represents one effective means of survival. Intelligence is our functional substitute for the numerousness of termites, the ferocity of lions, or the toughness of microorganisms. So, it might even be said that this is our specific manner of fighting the battle for survival: we would not be here if our intelligence-led rationality were not survival-conducive. But does all this mean that intelligence is an inevitable feature of conscious organic life? The answer to such a question is crucial and, as long as Rescher is concerned, is negative.”

From: Rescher, Nicholas | Internet Encyclopedia of Philosophy