Thinking, Fast and Slow

Daniel Kahneman’s Thinking, Fast and Slow is remarkable for the strength of its perspective into human reason, the clarity of its exposition, and the (ironic) lack of self-awareness of the author’s voice. I go through these three (of many) learning points from the book in sequence below.


The book’s argument is strong and nuanced. It claims that we should be self-aware of the two perspectives that we take when we go about doing stuff. These two perspectives are analysed into three levels of description – the psychological (System 1 and System 2), the practical (Humans and Econs), and the sentimental (experiencing and remembering self). The three-level dualism can be glossed as the study of the motivational structure of the prereflective and the reflective personas.[1]

The prereflective persona is the usual mode that we assume – or, more accurately, that we find ourselves in. This is the realm of instinct, intuition and impulse that spans Kahneman’s descriptions of System 1, Humans and the experiencing self. The prereflective persona acts seemingly without thinking and is most obviously identified when we imagine doing something while being bored out of our minds or while being immersed in ‘the flow’ and becoming one with what we do. (Ideas come together at the extremes, it seems – being bored is being in a state of flow, too, in a way.[2])

Take Kahneman’s example of the veteran firefighter who had a “sixth sense of danger” and “heard himself shout, ‘Let’s get out of here!’ without realizing why.[3] At the psychological level, System 1 perceives danger out of the norm for a fire scene and instinctively activates the firefighter’s flight response. At the practical level, the Human in the firefighter determined that the risk of the operation outweighed the expected reward and decided to abandon the task. At the sentimental level, the experiencing self felt “that the fire had been unusually quiet and that his ears had been unusually hot” and flagged the incident as alarming. These modes of explanation can be thus summarised: the firefighter entered the scene and prereflectively found himself escaping from it and urging others to do the same.

The reflective persona, on the other hand, is the mode we assume deliberately – we think about ourselves and what we are doing. This is the realm of introspection, inhibition and imagination that permeates System 2, Econs and the remembering self. The reflective persona puts itself out of step with the world and takes an “outside view[4] of itself. In several ways, we see ourselves more clearly because we notice our outlines. We know what we’re thinking or feeling, we tell a story about ourselves, we judge ourselves ‘impersonally’.

Kahneman illustrates the reflective persona through the example of Orley Ashenfelter’s wine investment formula[5]. At the psychological level, System 2 abstracts from the moment to rein in and modify the instinctive judgment based on tasting the wine. At the practical level, the Econ in Ashenfelter proposed and adhered to a formula to predict wine prices to guide his investment decisions. At the sentimental level, Ashenfelter activated his remembering self[6] to select the most important variables to include in the wine investment formula. To summarise, Ashenfelter reflectively constructed a course of action to maximise his return from his wine investments.

The value of Kahneman’s argument is that it is distinguishes the prereflective and reflective personas while being clear about how they are not utterly distinct. System 1’s instincts are prone to error and must be refined through feedback from System 2. But System 2 sometimes takes System 1’s inputs for granted and may veer off-course. Econs can construct elaborate models for rational action which Humans often do not adhere to. But the assumptions of rationality for Econs must be validated by the Human experience.[7]

Interestingly, Kahneman’s preference for the reflective over the prereflective persona is reversed at the third level of description. The remembering self retains the most vivid impressions from its past experiences to make decisions, but this reflective perspective contends with the here-and-now view of the experiencing self, which Kahneman thinks is more important. But this reveals that the title of his book is a little misleading. Rather than that slow thinking reins in the excesses of fast thinking, as we are wont to think going through the first 4 sections, Kahneman’s central claim is this: if our fast thinking were optimal, we wouldn’t really need slow thinking. The instantaneous experiencing self, the motivated Human, the instinctive System 1, they are the frame of reference for Kahneman’s idea of what being human means. Slow thinking only serves to optimise (or, for the third level of description, to hinder) the proper functioning of fast thinking.[8]

The viewpoint that Kahneman puts forth in Thinking, Fast and Slow, then, is that human reason operates in the paradigm of rationality, and our slow thinking systems are mostly designed to enhance the operation of our fast thinking systems. If we agree with him and apply the lessons learnt from this principle, the book provides deep insights to help us improve.


The other strength of Thinking, Fast and Slow lies in its clarity of exposition. Kahneman takes us through decades of his illustrious research career like a master storyteller. He recalls collaborations with other respected psychologists and economists like recounting stories with old friends, and introduces the reader comfortably to his pioneering work in prospect theory and behavourial economics. He is also consistently critical, analysing others’ thought and his own with the same standard of rationality that he describes in the book.

It is to Kahneman’s credit that reading his book is like having a sublime meal: the process was enjoyable, the flavours subtle and multifarious, and on reflection it demands to be relished again. Reflexively, after getting a fast impression of the book the first time round, it is worth going through a few more times over and digesting slowly, for us to hone the intuitions we have gained.


The third learning point is to do better where Kahneman’s book falls short, which is to take its own point of view for granted. Ironically, Kahneman’s own intuition about human reason is largely a product of prereflective rather than reflective thought. He presents the view of human reason as operating in isolated, forward-looking time-slices as though it were self-evidently true. Reason just is making the right decision in the moment, in light of the present situation and future prospects.[9]

But this assumption, which he never seriously thought was worth discussing, let alone challenging, dooms his aim to effectively criticise fast thinking from the start. As he was unaware of his own preference, he could only view the fast thinking system as a flawed approximation to the ideal state needing a remedy from the slow thinking system. If put uncharitably, Kahneman was going in a giant circle and going nowhere.[10]

Against Kahneman’s assumptions, fast thinking need not be the ideal standard of human reason. Taking a page from his book (Ch. 34, Frame and Reality), his frame of reference affects his view of the two systems. Fast and slowing thinking occur along a spectrum, but Kahneman presents them as though slow thinking was helping fast thinking catch up to its own ideal state. The true dichotomy to analyse is not within this spectrum of thought but rather between the rational actor model, stripped bare of human emotions and impulses, and the view of human being as whole and complete because of its imperfections and contradictions.


The challenge for reasoning about ourselves is to respond to our reality and embrace our humanity. Thinking, Fast and Slow provides a brilliant perspective into the functioning of our reasoning side, but that is not the whole picture of our mental lives. In order to do ourselves justice, we need to take into view our emotional, aesthetic aspects too.


[1] I adapt this term from Jean-Paul Sartre’s Being and Nothingness, in which he presents his philosophy of existence. I use ‘persona’ rather than ‘self’ because the self is one of the most loaded and frustrating concepts in philosophy. (This is not to say that ‘persona’ is problem-free, only that it takes us through fewer minefields.)

[2] See David Foster Wallace’s The Pale King and Martin Heidegger’s The Fundamental Concepts of Metaphysics for a literary and philosophical take on this musing, respectively.

[3] Kahneman (2011), p. 11.

[4] Kahneman, p. 245.

[5] Ibid, p. 223.

[6] Kahneman notes that “the correlation between his [Ashenfelter’s] predictions and actual prices is above .90.” (Ibid, p. 224.) If Ashenfelter were an ideal prospective Econ and not a remembering Human, the formula should include all relevant variables and the correlation should be 1.

[7] Kahneman makes this implicit point in describing the emergence of behavioural economics to account for the weaknesses of the rational agent model. (Ibid, pp. 269-88)

[8] Kahneman occasionally praises System 1, which suggests that he holds an ideal view of its proper function and is merely focusing on obstacles to that ideal in the book. At peak function, a well-honed System 1 leads to expert intuition and ability in, say, chess. (Ibid, pp. 236-9) And he concludes by saying that System 1 “is the origin of most of what we do right – which is most of what we do.” (Ibid, p. 416)

[9] A few choice examples: “What we learn from the past is to maximise the quality of our future memories, not necessarily of our future experience. This is the tyranny of the remembering self.” (Ibid, p. 381) “Odd as it may seem, I am my remembering self, and the experiencing self, who does my living, is like a stranger to me.” (Ibid, p. 390)

[10] He does make a half-hearted acknowledgement of his narrow point of view: “We cannot hold a concept of well-being that ignores what people want. On the other hand, it is also true that a concept of well-being that ignores how people feel as they live and focuses only on how they feel when they think about their life is also untenable. We must accept the complexities of a hybrid view, in which the well-being of both selves is considered.” (Ibid, p. 402)


The Art of War

Sunzi’s The Art of War is, historically, a strategic military manual, written 2,500 years ago in feudal China, elaborating the principal considerations of conducting organised state warfare against another state. It is a remarkable text for the broad applicability, across time and space, of the principles it elucidates for many social contexts in which one party is in competition with another. I identify three organising themes of the text, which are: the virtuous valiant, the autonomous arena, and the strategic substantiality.


The virtuous valiant is the general who glorifies his/her king and country; or the CEO who advances the interests of his/her shareholders and firm; or the entrepreneur who blazes the trail for his/her society and ambition. He/she is anyone who is committed to other people and to an ideal, and takes action and leads others in order to honour that commitment.

The virtuous valiant is virtuous because there is a standard of character demanded of him/her. The Art of War says: “The General must be possessed of wisdom, honesty, benevolence, courage and discipline.[1] The virtuous valiant is valiant because he/she must put him/herself forth to lead others to honour his/her commitment. This also requires wisdom on his/her part, to know the virtues demanded of him/her and to know that amongst everyone he/she is best placed to take the lead.[2]

How do the virtues play out? The valiant must “bring your troops together with humane treatment, and bind them with discipline.” He/she must be fair and consistent with reward and punishment to those whom he/she leads to secure their loyalty.[3]  He/she must care for his/her followers but also demand performance.[4] He/she must be able to unite them under his/her leadership, such that they will follow him/her unreservedly. [5]

Crucially, the virtuous valiant is committed to others and to an ideal he/she holds; hence he/she must be humane. Leading others to war, to any form of competition is costly, and the valiant must empathise with the costs borne by his/her followers while taking the courage to incur those costs.[6] Having foreknowledge of and planning for the fight is thus also highly important. This brings me to the second organising theme, the autonomous arena.


The autonomous arena is the space in which the virtuous valiant leads his/her followers to fight for his/her commitment. It is an arena or an environment which is climatic and terrene.[7] There are pervasive or structural factors (which can be analogised to Sunzi’s Heaven) and concrete or individual factors (Earth) which need to be understood. In the battlefield, Heaven is the sun, the rain, the seasons, and Earth is the mountains, valleys and rivers. In business, Heaven is the policies, tax regimes, technologies pertaining to the valiant, and Earth is the field of competitor firms, clients and other stakeholders.

The arena is autonomous in having its own logic of action.[8] For Sunzi, “War is the place where life and death meet; it is the road to destruction or survival. It demands study.[9] He elaborates the logic of war in brilliant detail throughout the Art of War: “first comes scoping, then measurement, then calculation, then balancing, and finally victory.[10] Knowing the 6 types of natural terrain (地形篇) and the 9 types of military ground (九地篇) lets the valiant set the scope of battle, whereupon he/she can measure the troops and resources needed to conduct battle, calculate the distribution of troops and resources against the enemy, balance that distribution according to the arena in play, and fight for victory. The analogy to business is clear: the autonomous logic of economic competition requires understanding the playing field and the implications of environmental factors on one’s business strategy. This pertains to the third organising theme, strategic substantiality.


The Art of War is often (mis-)quoted for its advocacy of “Deception”, or 诡. On first pass, it seems to be saying that war is fundamentally duplicitous – the text begins by stating: “when you are able to act, feign incapacity; when deploying, feign inactivity; when you are close, appear to be far off; when you are distant, appear close. When your enemy seeks an advantage, lure him further; if he is in disorder, crush him; if he is organised; be ready for him; when he is strong, avoid him; when he is angry, goad him further; if he is humble, be overbearing; if he is resting, harry him; if his armies are united, split them. Attack where he is unprepared, appear where you are least expected.[11] But if the general is a virtuous valiant, how can he/she resort to deception? In fact, this is a distraction.

Sunzi’s point, and genius, is that the autonomous logic of warfare is strategic substantiality. War is costly to the general and the country he defends; hence the virtue of humaneness requires the general to minimise this cost. This is why “winning a hundred victories out of a hundred battles is not the ultimate achievement; the ultimate achievement is to defeat the enemy without even coming to battle.[12] Within the logic of warfare, death and deceit are accepted norms. Hence Sunzi advocates the strategic employment of espionage (用间篇) and deception (虚实篇) to maximise one’s advantage over the enemy while minimising one’s cost.

The principle underlying deception is substantiality. To see this, consider substantiality in terms of the men and resources committed to an objective. A commitment is substantial if, for example, a frontal attack is promised and executed. A commitment is insubstantial if there is an expectation of a frontal attack but what is executed is instead a flank. Hence the principle of substantiality consists of expectation and substance. What Sunzi means by deception is then the management of substantiality (expectation and substance) to maximise one’s advantage over the enemy while minimising one’s cost. Seen in this way, deception obeys the autonomous logic of warfare while respecting the humaneness of the virtuous valiant.


Successfully grasping the three organising themes of virtuous valiant, autonomous arena and strategic substantiality lets one be highly capable and adaptable to succeed in honouring whatever commitment he/she has. One becomes like water. “Water adapts its course according to the terrain; in the same way you should shape your victory around the enemy’s dispositions. There are no constants in warfare, any more than water maintains a constant shape.[13] In the dynamic and evanescent context of war, business, or any form of social competition, Sunzi offers sage advice for anyone who wants to come out on top.


[1] “将者,智·信·仁·勇·严也。” 始计篇。 I rely on James Trapp’s (2012) translation, published by Chartwell Books.

[2] There is a reflexive moment in the text, where Sunzi begins by imploring the reader (the would-be virtuous valiant) to plan for war and to study the five decisive factors, one of which is the virtues of the general.

[3] “卒未亲附而罚之,则不服,不服则难用也。卒已亲附而罚不行,则不可用也。故令之以文,齐之以武,是谓必取。令素行以教其民,则民服;令不素行以教其民,则民不服。令素行者,与众相得也。” 行军篇。

[4] “视卒如婴儿,故可与之赴深溪;视卒如爱子,故可与之俱死。厚而不能使,爱而不能令,乱而不能治,譬若骄子,不可用也。” 地形篇。

[5] “故善用兵者,携手若使一人,不得已也。” 九地篇。

[6] “凡兴师十万,出征千里,百姓之费,公家之奉,日费千金;内外骚动,怠于道路,不得操事者,七十万家。相守数年,以争一日之胜,而爱爵禄百金,不知敌之情者,不仁之至也,非人之将也,非主之佐也,非胜之主也。” 用间篇。

[7] “天者,阴阳、寒暑、时制也。地者,远近、险易、广狭、死生也。” 始计篇。

[8] James Trapp notes in his translation of the Art of War that “Sunzi’s approach to war is entirely pragmatic … The General’s ‘Moral Compass’ applies only to his attitude to his ruler.” The logic of warfare is, he claims, completely independent of the moral considerations of initiating war. I am not able to deal with this complex topic in this essay, as “Moral Compass” is his translation of 道, or the Taoist concept of the Way, which is an issue for another day.

[9] “兵者,国之大事,死生之地,存亡之道,不可不察也。” 始计篇。

[10] “兵法:一曰度,二曰量,三曰数,四曰称,五曰胜。” 军形篇。

[11] “故能而示之不能,用而示之不用,近而示之远,远而示之近;利而诱之,乱而取之,实而备之,强而避之,怒而挠之,卑而骄之,佚而劳之,亲而离之。攻其无备,出其不意。” 始计篇。

[12] “是故百战百胜,非善之善者也;不战而屈人之兵,善之善者也。” 谋策篇。

[13] “夫兵形象水,水之形,避高而趋下,兵之形,避实而击虚。水因地而制流,兵因敌而制胜。故兵无常势,水无常形,能因敌变化而取胜者,谓之神。” 虚实篇。

Shine bright like a diamond

We’re beautiful like diamonds in the sky ~

We are all, each of us, diamonds. Carbon-based organisms that we are, we get pressed in from all sides by the pressures of the world.

We crystallise into something stronger, more graceful, more luminary. And we light the way for others to come.

lillamp is the story of two diamonds who shone into each other’s heart and discovered a dazzling kaleidoscope of colours.

May our reflections and refractions of light be illuminating to you, too.