REO Speedwagon asked that question in Hi Infidelity. Ilsa faced it at the end of
Things exist for a reason. Reason and instinct are no different. Both are means of survival. Instinct, present in all forms of animal life, provides instantaneous decisions that increase the odds of survival in cases of immediate danger. There is no time for reason when one is pursued by a dangerous animal, so it is instinct that keeps one alive. For humans, whose physical capabilities are less than those of most animals, reason allowed for the creation of tools and other methods to overcome their physical deficiencies, thus increasing survival rates. An unarmed human stands little chance to defeat a buffalo, but working in tandem with others armed with weapons, humans can defeat the animal and enjoy all the benefits it provides.
Likewise, both instinct and reason have times and places where they are more useful. Instinct’s ability to provide one with a rapid response is critical in situations where time is of the essence while reason is necessary when one has adequate time and is attempting to find a solution that works in all situations and not just the present moment. In situations like sports and battle where time to react is measured in increments smaller than a second, decisions based on instinct are the only way to go. However, instinct will provide little help in finding a solution to a scientific problem because it only considers the present moment and cannot consider the full possibilities and limitations of different circumstances. In long-term projects reason dominates.
Clearly, both reason and instinct have their places in life and to give one such heavy preference that the other is completely excluded would be a grave mistake. As depicted in popular media, humans have a strong aversion to being reduced to a computer or animal, the respective epitomes of dominance by reason and instinct. But, as is the case of many dualities, granting greater weight to one is appropriate. Aristotle in his formulation of the Golden Mean, an idea that continues to inform our practice of virtue today, admitted that courage is not found square in the middle of foolhardiness and cowardice but more on the side of foolhardiness.
Thus I give priority to reason. Between it and instinct, reason is the only one that can take advantage of the benefits of each. Should the situation demand it, reason can recognize the instinctive choice, abdicate decision-making to it and take control again when the situation has changed. In contrast, should preference be given to instinct in the decision-making process, reason will not have the opportunity to surface and its advantages will never be known because instinct is instantaneous and offers no time for the reflection required for reasoned choices.
Furthermore, reason can form positive instincts, but instinct can never make reason sharper. For example, many aspects of the martial arts are antithetical to a natural, instinctive response; one steps into an attack rather than flees, attacks are carefully restrained to prevent a powerful counter. One fails in the martial arts not only if they trust completely to their natural instincts but also because they are too slow if they attempt to reason through every move. Through practices constructed and guided by reason, however, poor instincts can be replaced with superior ones. Thus instinct retains its usefulness through the use of reason.