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  • Brittany

The Reason for Reason

Exploring the Interaction Between Rationality and Sociability

I’m always looking for a deeper understanding of human nature, particularly about the relationship between our rationality and sociability. The ancient Stoics, as you know, posited that our reasoning ability and our social gregariousness are the defining features of humanity. They make us who we are and undergird the instincts that drive our development toward virtue. However, the ancient Stoics didn’t really address the relationship between our rationality and sociability.[1] This is an important question for us moderns to answer in our own interpretation of Stoicism.

So I was delighted to come across an excellent book, The Enigma of Reason, that answers this question in a novel and, for Stoics, very relevant way. Cognitive psychologists Hugo Mercier and Dan Sperber argue that reason didn’t evolve as a solitary endeavor to improve our powers of logical abstraction. Instead, reason is the result of our ecological niche as a hypersocial species:

Whereas reason is commonly viewed as a superior means to think better on one’s own, we argue that it is mainly used in our interactions with others. We produce reasons in order to justify our thoughts and actions to others and produce arguments to convince others to think and act as we suggest. We also use reason to evaluate not so much our own thought as the reasons others use to justify themselves or to convince us.[2]

Calling their theory an “interactionist” account of reason, Mercier and Sperber present compelling evidence that our reasoning ability evolved to grease the wheels of social cooperation. In a group of highly intelligent creatures who must cooperate to survive—and who have the gift of human language —each individual needs to present herself (and her ideas) to others in the most positive light possible. At the same time, she needs to evaluate the actions and opinions of others in the group. Are they trustworthy? Do their ideas solve the problem we’re facing right now? Should I do what they say? We have a vested interest in carefully evaluating the explanations and arguments other people put forward, while confidently promoting our own.

As a result of these evolved social needs, Mercier and Sperber contend, our reasoning process is based on inference rather than any sort of logical deduction. We make intuitive inferences about the world based on our experience, and what we call “reason” is simply our post-facto intuitions about our reasons. In other words, we reason about our inferences after they happen. Or you could say we reason not in order to decide what to do, but to explain our actions to ourselves and others after the fact. As Mercier and Sperber put it:

Humans have limited knowledge of the reasons that guide them and are often mistaken about these reasons. It is not that we commonly misidentify our true reasons. It is, rather, that we are mistaken in assuming that all our inferences are guided by reasons in the first place. Reasons play a central role in the after-the-fact explanation and justification of our intuitions, not in the process of intuitive inference itself.[3]

Starting from this basic premise, The Enigma of Reason supplies a great many examples of how reason is well-suited to social argumentation and poorly suited to solitary deliberation. That’s because reason is subject to a strong myside bias (also known as confirmation bias), wherein we tend to look for confirmation of our existing opinions. Our brains seem adapted to latch onto evidence in support of our pre-existing views and to overlook evidence contrary to them.

Myside bias is usually cited as a flaw in our reasoning ability. Mercier and Sperber, however, see it simply an adaptive feature of our highly social environment. When two individuals or groups engage in interactive reasoning—also known as argument or debate—each side tends to identify flaws in the arguments of the other side. This is adaptive because it’s easier for me to let you identify the flaws in my opinion than for me to expend effort identifying them myself. Yet the end result is that flaws are exposed on both sides, and each side will have to respond to these flaws if they want their opinion to carry the day. Whoever is able to address these flaws and persuade the other side is the winner.

The problem arises, according to Mercier and Sperber, when people do not engage in interactive argumentation. This could happen when one person reasons alone, without input from anyone else, or when a group forms in which everyone holds exactly the same opinions. (Or perhaps a more common occurrence: a group forms in which people are afraid to express opinions contrary to the most powerful opinion-holder.) In this case, the myside bias is amplified rather than corrected. A group in which no one is able or willing to dissent prevents people from being exposed to flaws in their own arguments.

One of the main theses of the interactionist hypothesis, then, is that human reasoning works just fine in its proper evolutionary niche: interactive disagreement in an egalitarian group. But it frequently malfunctions outside of that niche. That would explain not just the crazy social breakdowns on Twitter but also why individual pathologies might develop when people are isolated from supportive social input. (Here I'm thinking of unhealthy rumination associated with anxiety, depression, and some other disorders.)

Mercier and Sperber’s hypothesis might sound counterintuitive at first, but I find their argument from evolutionary adaption to be very persuasive. Evidence from evolutionary anthropology, developmental and child psychology, and other cognitive sciences continues to pile up, suggesting that humans’ intelligence and sociability evolved in tandem. Our extreme cooperativeness and our rationality are inextricable. (If you are interested in reading further on this topic, I will share some of my favorite books under Suggested Reading at the end.)

To me, the clear analogue to an interactionist view of reasoning is language. Humans surely didn’t develop linguistic ability to enable one individual to communicate with herself; language must have developed to communicate with other people in the group. And yet, once we develop the ability to talk with others, we can also use that ability to talk to ourselves, in our own minds. Our intelligent brains co-opt a function that evolved to facilitate cooperation with others, turn it inward, and use it for a purpose other than that for which it evolved (i.e., talking to ourselves). But even though we can use language to clarify our own thoughts to ourselves, we still use it primarily to communicate with others. That is its primary function and the one for which it is best suited.

This analogy with language is one reason I find the interactionist account to be so credible. But another is how well it fits the available evidence for how people use their reasoning ability. We all know how ingrained the myside bias is in most people most of the time. In recent decades some psychologists have suggested that human rationality doesn’t exist, or that it is irredeemably flawed, because it seems to be so bad at objective reasoning tasks. But the evidence coming out of psychology makes sense when you think that reason is supposed to be used in an interactive context. As Mercier and Sperber argue, reason often works well in the context for which it evolved.

Now, I’m clearly not a cognitive psychologist, so I’m not in a position to judge the merits of the interactionist hypothesis from a scientific point of view. I’m mainly interested in whether it can help me better understand my experience as a human. And I find that, after reflecting on this hypothesis in relation to how the mind works, it does offer some novel insight into our experience of the reasoning process. That's what we'll discuss in the next section.

The Interactionist Approach and Stoicism

At this point you might be wondering how on earth the interactionist approach could apply to Stoicism at all, or you might be thinking that it actually undermines Stoicism’s focus on perfecting our individual reasoning ability. Mercier and Sperber might even agree with you about this, since they pit their interactionist theory against the "intellectualist” theories of traditional philosophy and psychology.

But in fact, I think the ancient Stoics would completely agree with this negative assessment of our untrained reasoning ability. That’s why they insist on training our reason through unremitting philosophical practice. We must work extremely hard to overcome personal biases, lazy thinking, and unfounded assumptions. This is the first and most important task of philosophy. Epictetus talks about this task continuously throughout the Discourses:

The most important task of a philosopher, and his first task, is to test out impressions and distinguish between them, and not to accept any impression unless it has been duly tested. (1.20, 7)

This, then, is the first step in philosophy, to become aware of the condition of one's ruling center. For when a person comes to know it is in a weak state, he will no longer wish to employ it on matters of importance. (1.26, 15)

The point of departure in philosophy, at least for those who embark on it in the proper way and enter by the front door, is a consciousness of our own weakness and incapacity with regard to essential matters. (2.11, 1)

What is the first task for someone who is practicing philosophy? To rid himself of presumption: for it is impossible for anyone to set out to learn what he thinks he already knows. (2.17, 1)

It was very obvious to the Stoics, from Zeno onward, that most people tend to act first and then try to justify their actions to themselves and others. And it was equally obvious that this inconsistency in purpose and action resulted in unhappiness—as Epictetus puts it, “self-reproach and inner conflict and instability of mind and self-torment" (Discourses, 2.22, 35).

The ancient Stoics also recognized that people start out with a myside bias toward their own opinions and that, if unchallenged, they would blithely assume they are right about everything. We become motivated to change our thought processes when it dawns on us that our own opinions are different from other people’s, and that we don’t actually know who is right:

Look now, this is the starting point of philosophy: the recognition that different people have conflicting opinions, the rejection of mere opinion so that it comes to be viewed with mistrust, an investigation of opinion to determine whether it is rightly held, and the discovery of a standard of judgment, comparable to the balance that we have devised for the determining of weights, or the carpenter's rule for determining whether things are straight or crooked. (Discourses, 2.12, 13)

In other words, the starting point of philosophy is realizing that we hold different opinions from other people—a view that tends to support the interactionist hypothesis of reasoning. It’s not that we’re sitting at home in an armchair by the fire doing thought experiments. (Not most of us, anyway.) It’s in the course of living our lives, bumping up against the divergent opinions of people, and realizing we can’t all be right. We begin our philosophical quest with the need to develop a systematic framework for our actions, rather than relying on the post-hoc justifications that dominate casual thinking.

The Stoics developed brilliant techniques for correcting these weaknesses in our rationality. What’s extremely interesting to me, in light of the interactionist approach proposed by Mercier and Sperber, is how extremely dialogic these techniques are. The Stoics realized that our reasoning responds to interrogation, and they co-opted our natural ability to argue with other people for the purpose of correcting our own inner monologue. How do you overcome the pitfalls of a monologue? By turning it into a dialogue, of course.

In fact, Western philosophy itself is founded on the dialogues of Socrates, who spent his life debating with other people. Socrates would engage in interactive argumentation with anyone, anywhere, at any time. Of course, his style of dialogue was a bit different from the classic debate scenario of one opinion versus another. Socrates drew out opinions from his interlocutor with a series of cascading questions, while claiming not to have any reliable knowledge on the topic himself. Plato called this technique elenchus. It is at once “interrogative, examinational, prosecutorial, and refutative,”[4] but above all it is an interactive encounter between two (or more) people.

This dialogic beginning to the Greek philosophical tradition chimes quite well with the interactionist hypothesis. And we know that philosophy remained a very social and dialogic pursuit throughout antiquity. Most philosophical development, both between and within schools, happened as a result of discussion and debate. Philosophy was not originally intended for individual, private consumption.

Except that sometimes it was. Another brilliant innovation of the Hellenistic schools (not just the Stoics, but also the Epicureans) was to co-opt the dialogic nature of our reasoning ability for personal use. If we want to avoid the pitfalls of the myside bias, we need to transform our inner discourse from a monologue to a dialogue. In the absence of a teacher, friend, or disputant, we must turn the tables and ask ourselves questions.

So, for example, we see Seneca engaging in self-examination every night by asking himself questions. We see Marcus Aurelius dialoguing with himself in his philosophical journal. And we see Epictetus urging his students to question their basic assumptions by interrogating themselves, the way you might debate with another person:

Living as we do among such people, who are so confused, and don't know what they're saying, or what evil they have within them, or where they got it from, or how they can get rid of it, we should constantly be focusing our attention, I think, on the following thoughts: “Could it be, perhaps, that I too am one of these people? What kind of person do I picture myself as being? How do I conduct myself? Is it really as a wise person, as someone who has control of himself? Can I say for my part that I've been educated to face everything that may come? Is it indeed the case, as is fitting for someone who knows nothing, that I'm aware that I know nothing?” (Discourses, 2.21, 8-10)

The ancient Stoics brilliantly used the dialogic nature of human reasoning to our advantage. By shaping our opinions in advance—preparing ourselves for hardship, reminding ourselves of the reserve clause, shaping our preconceptions toward virtue—we are primed for virtuous action. We don’t have to stop and think about it when the need arises; we already know what’s important and how to respond.

This strategy addresses the underlying problem that Mercier and Sperber probe with their claim that “what reason does is draw inferences about reasons”5. Our reasoning ability, as actually used in real life, is not a chain of logical deductions but an intuitive inference about why we do the things we do. Our brain evolved to solve real-world problems at lightning speed, and it’s easy to see why. If we had to stop and consciously puzzle our way through every decision, we wouldn’t survive for long. Most of the time it’s in our best interest to act first and think later.

So Stoicism uses a two-pronged approach to help us make better decisions about our lives. The first step involves asking us to think about the underlying values that shape our decisions. We reflect on these and decide what our values are before we ever need to act, so that when the time comes to act we already know what we need to do. As our brain quickly jumps into gear to make inferences about our intuitions, we find that our intuitions (about hardship, poverty, death, illness, wealth, friendship, relationships, and everything else in life) reflect our previously-decided values. We can spontaneously act in a way that aligns with our desire for virtue.

The second step is putting distance between the stimulus and the response (echoing Viktor Frankl here) by learning to question our intuitions before we act instead of after. This is how Epictetus describes questioning our impressions:

If you muster these thoughts against it, you'll overpower your impression and not be swept away by it. But first of all, don't allow yourself to be dazed by the rapidity of the impact, but say, “Wait a while for me, my impression, let me see what you are and what you're an impression of; let me test you out.” (Discourses, 2.18, 23)

For just as Socrates used to say that we shouldn't live an unexamined life, we shouldn't accept any impression without subjecting it to examination, but should say to it, “Wait, let me see who you are, and where you've come from”—just as night watchmen say: “Show me your mark of identification.” — “Do you have that mark from nature that every impression must have if it is to be accepted?” (Discourses, 3.12, 15)

We learn to recognize value-laden triggers, such as seeing a rich or famous person in the street and wishing we could be like them. Instead of simply accepting the impression—and sighing to our friend, “Wouldn’t it be great to be rich and famous?”—we recognize this inference as problematic for our own happiness. We don’t assent to the intuitive impression that pops up in our minds. We train ourselves to develop new intuitions:

As we train ourselves to deal with sophistical questioning, so we should also train ourselves each day to deal with impressions, because they too put questions to us. “The son of so-and-so has died.” Reply: That lies outside the sphere of choice, it is nothing bad. (Discourses, 3.8, 1-2)

It’s extremely interesting that Epictetus explicitly draws attention to the Socratic nature of questioning our own impressions. And, of course, Epictetus’ teaching style is heavily influenced by Socrates in the first place. (You can read Epictetus’ own extended description of Socrates’ art of argument in Discourse 2.12.) He often uses the elenctic back-and-forth with his students to draw out their reasoning, and he encourages them to use this same technique with themselves when he is no longer with them. This ensures they will be able to question their own impressions after they graduate from his school and go off to become government officials around the Roman empire. It seems that Epictetus understood very well the necessity of dialogue in human rationality.

Why Study Cognitive Science?

I hope you’ll agree that the ideas presented here, drawing on The Enigma of Reason by Hugo Mercier and Dan Sperber, are highly relevant to our practice of Stoicism. This where I introduce some caveats. Some people might think it doesn’t make sense to bring cognitive psychology into the study of a philosophy of life, so I just want to explain what I hope to gain by doing this.

First, I don’t mean to imply that Stoic ideas, particularly Stoic epistemology or the theory of impressions, map neatly onto Mercier and Sperber’s interactionist account of reason. There are some differences and some potential clashes. Nevertheless, there are enough areas of overlap, and so many potentially helpful insights, that I think it is still worth a careful parsing of the theory. Even if some particulars of the theory don't align, in broad outline the interactionist hypothesis is well worth considering.

My point in this essay is not to claim that this theory “supports” Stoic psychology. Stoic psychology doesn’t actually need the support of modern cognitive psychology. Stoic psychology has stood on its own two feet for millennia as an accurate phenomenological description of our real-life mental experiences. That’s why it speaks to us just as loudly today as it did 2,000 years ago, despite our considerably more advanced contemporary understanding of how the brain works.

And Stoicism will continue to be relevant to people of the future no matter how much or how little we learn through the cognitive and neurosciences. Scientific theories come and go, and it's risky to tie a philosophy to a particular scientific paradigm; we all know that most scientific paradigms eventually fall. Old theories are hopefully replaced by theories of more power, depth, and accuracy, but that may not always be the case. There is no guarantee that our understanding of something as notoriously difficult as the human brain—the most complex structure in the known universe—will ever be settled. I have a feeling there will always be more to learn.

So just to be clear, I’m not suggesting that the interactionist approach of Mercier and Sperber somehow proves or validates Stoicism. I’m also not trying to paper over some of their key differences (which would certainly prove my own bias in trying to make everything in the world fit into Stoicism!). I think the interactionist hypothesis and Stoicism are each valuable in different domains. Stoicism is valuable today as a life philosophy, not as a scientific representation of how the brain works. And Stoicism will remain valuable as long as the human brain continues to work in the same way.

Still, I do think this the interactionist hypothesis can shed new light on the specific question of the relationship between human rationality and sociability. Stoicism already meets our need for describing our phenomenological experience, but it would be foolish to ignore scientific advances that can potentially increase our understanding of this experience. For me, this is one of the main reasons to study cognitive science. I am not a cognitive scientist, but even basic insights into how our brains work helps me to understand myself better from the outside in, as well as from the inside out.

In addition—as readers of Living in Agreement already know—humanist Stoicism is premised on a thorough understanding of human nature. Human nature is a very broad term, of course, and on this site I try to explore it from different angles. One important angle is cognitive psychology, which can offer not only new research methodologies but new ways of thinking about our minds. Newer is not necessarily better. But sometimes new ways of thinking are just what we need to push us toward deeper wisdom. And when it comes to understanding how our minds work, I, for one, will take all the help I can get.

Concluding Thoughts

There’s a lot going on here, so let’s recapitulate the primary takeaways for a practicing Stoic:

  • Human reasoning, like human language, may have evolved to enhance our social cooperation. It is adapted for an egalitarian, interactive context in which people use discussion and argumentation to try to persuade others.

  • Human reasoning is well suited to the purpose for which it evolved: interactive deliberation. Outside of this context, it can be marred by myside bias (as well as other cognitive biases such as belief perseverance, overconfidence, and polarization).

  • Due to adaptive pressures, humans tend to act first and then justify their actions to themselves and others after the fact. Much of our reasoning ability is devoted to making ourselves look good in our own eyes and to other people.

  • Stoicism recognizes and addresses these “flaws” in human reasoning. The ancient Stoics used to say that all adult humans have rationality, but we can make better or worse use of our rationality. Making good use of it means we know how our minds work and we develop strategies to counter our natural tendencies to lazy thinking, unfounded opinions, and myside bias.

  • Remember, living in agreement with nature doesn’t mean just doing whatever comes “naturally.” In that case, we would get angry at the slightest provocation and eat sweets whenever we see them! Instead, the Stoics thought we are naturally formed to develop toward wisdom and maturity, so this is our “natural” condition.

  • Greek philosophy was very dialogic (as would be predicted by an interactionist view of human reasoning), beginning with the dialogues of Socrates. Epictetus continued the elenctic tradition in his own teaching and encouraged his students to use a dialogic format in their own private thoughts.

  • We can take advantage of the dialogic nature of human reasoning by:

  1. Training our intuitions toward virtue, so we are ready to spontaneously respond in a virtuous way when action is required. We prepare by reflecting on our values, premeditating adversity, and practicing spiritual exercises to shape our intuitions.

  2. Learning to question our impressions, giving ourselves a moment to think about our responses to value-laden stimuli in the world. We withhold our assent from these knee-jerk intuitions, instead reminding ourselves to live in agreement with nature.

I hope this perspective gives you insight into your own reasoning ability. Our goal is a deeper understanding of what it means to be human and how we can translate these insights into a flourishing life. In keeping with the dialogic nature of reason, please let me know in the comments if you have any replies, counterarguments, or questions.

Suggested Reading

This is a completely subjective list of my favorite books on the interplay between rationality and sociability, how these traits might have evolved in our species, and how they develop in children:

  • Becoming Human: A Theory of Ontogeny, by Michael Tomasello, 2019, Harvard University Press.

  • Survival of the Friendliest: Understanding Our Origins and Rediscovering Our Common Humanity, by Brian Hare & Vanessa Woods, 2020, Random House.

  • The Anthropology of Childhood: Cherubs, Chattel, Changelings, by David F. Lancy, 2015, Cambridge University Press.

  • The Cultural Nature of Human Development, by Barbara Rogoff, 2003, Oxford University Press.

  • The Enigma of Reason, by Hugo Mercier & Dan Sperber, 2017, Harvard University Press.


[1] At least, our surviving Stoic sources do not address this directly. Perhaps they addressed it quite clearly in works that have now been lost.

[2] Hugo Mercier and Dan Sperber, The Enigma of Reason, p. 7

[3] Hugo Mercier and Dan Sperber, The Enigma of Reason, p. 117

[4] A.A. Long, Epictetus: A Stoic and Socratic Guide to Life, 2002, Oxford University Press, p. 55

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