The disadvantages of being a purely rational person

Scientists and atheists are among groups of people who value rational thinking, the former because being rational and logical in one’s thinking is essential if one is to be able to navigate one’s way through the complexities of trying to understand the workings of nature, the latter because taking a rational approach to life would make the absurdities of religious beliefs and the behaviors they generate more manifest. But of course, none of us can be purely rational beings in every aspect of our lives. The emotional centers of our brains respond to stimuli in ways that can overpower the centers that govern rational and logical thinking, as all of us can testify from personal experience when we have done soothing impulsive and stupid.

But even if it were possible to be a purely rational being, would that even be a good thing? Probably not. Apart from the fact that life might be a little dry, we would be paralyzed with indecision about almost everything. Most of the decisions, big and small, that we make in our lives involve many variables and there is no obvious guidance as to the relative weights we should assign to them in order to arrive at a decision. Hence even in deciding something simple like what to eat for breakfast, it would be possible to go back and forth between many options weighing the merits and disadvantages of each. Should we go with the best price? The most tasty? The most healthy? The most attractive looking? The most convenient? It is often irrational emotions that enables us to avoid endless vacillations and decides things for us.

NPR had a story following the death of Leonard Nimoy who played the famously logical Mr. Spock on Star Trek.

There’s a scene toward the end of the 2009 “Star Trek” film in which Zachary Quinto, who now plays Spock, encounters his older self, Spock embodied by Leonard Nimoy. The metaphysics get a little confused, but wise, old Spock, who’s been around the heavens, advises his younger self to continue his mission among the stars.

NIMOY: (As Spock Prime) Spock, in this case, do yourself a favor – put aside logic. Do what feels right.

Sound advice from someone who lived long and prospered.


  1. flex says

    A number of years ago a friend wanted me to help him purchase a car. What he wanted was someone drive him around to various dealer, ride in the car during the test drive, and be a sounding board for his thoughts.

    Okay, not a problem. I rather enjoyed it. Until about the 4th car.

    By then it was clear that he really liked one model, and the only thing he was doing was criticizing every other model he drove in order to convince himself that he was making the most rational decision by choosing the car he liked.

    So I told him, “It’s clear you’ve made up your mind. Stop wasting your time, and mine, by looking at other cars. The car you want may not have the best mileage, or the most features, or be the lowest price. But if you will be unsatisfied with other models, you might as well get the car you want. It’s not beyond your means, it has decent mileage, and the features you desire. So go buy it already and don’t feel guilty about not comparing every possible vehicle to the one you have already decided to get.”

    Life is to short to waste time trying to make every decision on a strictly rational basis.
    Some decisions need to be data-driven and logically thought out.
    Other decisions, not so much.

  2. Chris J says

    I think “rational” is more flexible than you give it credit for, Mano. A lot of the definition of the word “rational” is linking it with being reasonable, or sensible. A person that becomes paralyzed with every decision is not behaving in a way we’d consider reasonable. A purely rational being would simply be one that always makes the best use of the evidence available, seeking out more if it’s necessary or useful or expedient, but falling back to intuition when practical. They wouldn’t get caught up in over-thinking mundane decisions.

    It still may not be something humans are capable of, but I hardly believe it’s a bad ideal.

    I really dislike the notion that rationality is somehow deficient, dry, or lacking in humanity. There is no aspect of a decision that doesn’t factor into rational thinking; if a supposedly “purely rational” wonders endlessly about what to eat for breakfast and ends up never eating, it just means they never factored in the detriments of taking too long to decide, or the fact that there are plenty of breakfast decisions to be made over the course of a lifetime and one choice isn’t going to make that big of a difference.

  3. Chris J says

    Hell, a purely rational being would probably make many decisions that are locally sub-optimal (if there were such a metric), but better in the larger picture of living a happy, low stress life.

  4. moarscienceplz says

    Unfortunately, the Spock character was often written by people who were self-selected to love art and expressions of emotion and to distrust science and reason, and thus had already decided for themselves that logic and reason were antithetical to happiness and ‘human-ness’. They then “proved” their own predjudices to be correct by having contests between the “logical” Mr. Spock and the intuitive Captain Kirk which Kirk always won, of course. An obviously ridiculous example of this is that Kirk could always defeat Spock at chess by making illogical moves. In the real world, an illogical chess move is one that places you in a less advantageous position, so it would actually make it easier for a skilled player to defeat you, not harder. But the “fully-human” Kirk had to be shown as superior to the “coldly logical” Spock, so Spock must lose, even if it makes no sense.

    The Straw Vulcan is a nice examination of this.

  5. David Wilford says

    The common sense take on emotion vs. logic is played out on Star Trek by having the emotional Doctor McCoy and the logical Spock argue about what to do, but it’s generally Captain Kirk who makes the final decision after hearing both of them out. It’s formulaic of course, but it’s a formula that helped the Star Trek franchise last for decades so it works as a storytelling device well enough.

    Emotions themselves however aren’t really illogical, and do have a critical purpose for social animals, which we human beings are of course. One, they serve as ways for us to quickly respond to certain situations. Anger, for instance, when we want to fight. Fear, when we want to flee, etc. Second, emotions also serve as a way to signal others about our intentions. Calmly saying “I’m upset about this situation” isn’t the same thing as yelling it as you’re seeing red.

  6. doublereed says

    I greatly dislike characterizations that assume that emotions and rationality are opposed to each other. The fact is that emotions are far from random, and usually have extremely easy-to-trace causation. Emotions have a very clear logic to them, and suppressing that is completely irrational. Most instances where people are angry, sad, and frustrated are quite logical.

    Furthermore, phrasing them as opposed is often used as a rhetorical trick by conservatives and right-wing to dehumanize and marginalize people. When marginalized groups (especially blacks and women) get justifiably angry, the conservatives will simply speak calmly and declare themselves the victor because they were not emotional.

    The only real defense I’ve seen against this tactic is sarcasm (which allows someone to be biting and emotional without revealing it in their tone).

  7. brucegee1962 says

    Great point about sarcasm at the end, there, doublereed.

    I ask my students what the underlying emotional source of Swift’s “A Modest Proposal” is. Most of them don’t recognize (until I point it out to them) the consuming, burning, spittle-flecked anger that informs every line of that essay. He only reveals it once or twice, but when he does, it’s white-hot.

    Swift had on his tombstone ‘Here lies Jonathan Swift, where savage indignation can no longer lacerate his breast.’ What social good was ever achieved by emotionless people?

  8. Mano Singham says

    Whether emotions are logical/rational or not depends on the emotion. Some emotions (the reaction to danger that causes us to act instinctively without thinking things through) can be viewed as evolutionarily developed short-cuts to arrive at decisions that we would subsequently agree were perfectly logical/rational though we did not arrive at them that way, at least consciously.

    But other emotions are different. I don’t think that we can view as rational the emotions that drive us to do things that we know are bad for us, such as eat too much or the wrong kinds of food, smoke, drink to excess, etc. In those cases we are going against rational thought.

  9. Pierce R. Butler says

    In those cases we are going against rational thought.

    Not to mention the cases where we abuse others or get violent (with the usual self-defense etc exceptions), allow ourselves to be exploited, or self-delude. Rationality shapes relatively little in most people’s lives, iow.

  10. dmcclean says

    The fact is that emotions are far from random, and usually have extremely easy-to-trace causation.

    Easy for you to say, doublereed @6. I’m starting to agree with you, but that’s after several years of training on how to identify them and trace their causation.

    I agree with the larger thrust of your comment, though.

  11. EnlightenmentLiberal says

    I accuse you of a clear straw Vulcan. Your response in #8 still completely misses the point.

    In a certain sense, all of us here are hedonists. We live our life for our enjoyment (and the enjoyment of others [which might just be the result of our own enjoyment -- but that’s a separate discussion]). Enjoyment, satisfaction, fulfillment, happiness -- those are all emotions. The general metric of human well-being is a metric of emotional states. There is nothing irrational about wanting to live a good life and to take a rational set of actions to get you there and keep you there. Putting rationality on one end and emotions on the other end of a single spectrum is wrong. The straw Vulcan is a critique of that wrong move.

    Of course, there are times when short term pleasure and long term pleasure come into conflict. The rational answer isn’t necessarily to choose long term pleasure. It depends on the particulars. Even then, it’s a genuine question with lots of room for honest, rational, reasoned debate and disagreement.

    Of course, there are also times when instinctual reactions -- emotional reactions if you will -- come into conflict with reason. That alone doesn’t justify saying that rationality and emotions are incompatible.

    Spock’s character itself often understood this, but equally often Spock was completely oblivious. It depended on the writer. The very idea of a “purely logical” character devoid of emotion makes no sense -- there would be no motivation to get out of bed in the morning. Some of the writers of Spock understood this, and some of them did not. I much liked the writers who understood this, and properly portrayed Spock and the other Vulcans as merely being very good at controlling, perhaps suppressing, their violent emotions and their strong emotions, to avoid the pitfalls we mentioned above. Vulcans still operate with motivations, desires, wants, needs, etc.

  12. EnlightenmentLiberal says

    To be clear, one does not need to suppress strong emotions to the extend of your average Vulcan in order to avoid the aforementioned pitfalls and be rational. You can have (controlled) bouts of unmitigated joy and happiness, and still be rational. No contradiction here folks.

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