Think Again Book Review – The Power of Knowing What You Don’t Know


Welcome to my book review of Think Again by Adam Grant!

In this book review series, inspired by Seba and Jesus in The Business Kids Podcast, I review some of my favourites books and share the lessons I’ve learned through them. Every month I make it a habit to read anywhere from 3-5 books, so I’ll be picking out the best book of the month to share on here.

The format will go as follows:

  • Quick Summary of the Book
  • Key Ideas of the Book
  • What I Loved About the Book
  • What I Disagree About the Book
  • And finally, an overall rating of the book (rated out of 5 stars)

So, without further ado, let’s dive into this book review of Think Again!

Quick Summary

Think Again is written by award-winning psychologist and professor at Wharton Business School Adam Grant. In it, he documents the importance of well….. thinking again.

Grant begins the book by arguing that a lot of people are really good at thinking, but few are good at REthinking their existing beliefs. He makes the case that the skill of thinking again is more important today than ever before as the world moves faster and faster. Good news (or bad news depending on who you are) is that Grant ALSO found that the smarter one is, the worse they usually are at thinking again. Which means that you don’t need to be a genius to rethink.

Grant then splits up the book into three distinct sections:

  • Individual Rethinking
  • Interpersonal Rethinking
  • Collective Rethinking

The section on individual rethinking encourages us to look within and take a deeper delve into some of our existing beliefs. It’s here that Grant introduces the four “modes” (which we will talk about later). Interpersonal rethinking is all about making OTHER people think again (my favourite section). Grant talks about how an argument should be more of a dance/collaboration rather than a battle/prosecution. Finally, collective rethinking takes a broader approach and promotes the idea of rethinking being introduced at large. Adam discusses the importance of practicing rethinking in schools, at work (with NASA as one example), and even in everyday conversations.

Through example after example and Adam’s own willingness to rethink his views (which you’ll find time and again in the book), Think Again is a fantastic starting point for those who want to succeed in the modern world. Think Again helped me rethink some of my own views (as well as learn how to encourage others to) and I’m sure you’ll pull something useful out of it too!

Key Ideas from “Think Again”

Book Review of Think Again
Book Review of Think Again

Adam discusses so many ideas that it would be impossible to document them all here. But three that really stuck out to me were:

  1. The four “mindsets” or “modes”
  2. The Dunning Kruger Effect
  3. Identity foreclosure

The Four Mindsets

In the first section of the book, Adam Grant brings up this idea of people usually entering one of three mindsets:

  • Preacher
  • Prosecutor
  • Politician

When people have their own values attacked, they tend to enter preacher mode. This is where you give sermons and defend your ideas (much like a preacher) without really thinking critically about whether you’re right or not. When most people attack OTHERS’ ideas, they enter prosecutor mode. This is where you point out all the flaws in your opponents’ thinking and viciously attack them. Finally, there’s politician mode. This is where you nod along and say yes to someone’s beliefs for the sake of winning them over, when in reality, you haven’t actually changed your mind.

When it comes to thinking/talking about our beliefs, we usually fall into one of these three categories. However, as you may have noticed, none of them give very much room for rethinking. In preacher mode, we’re too busy defending to consider what we’re defending. In prosecutor mode, we just want to attack and bring down the other side, oftentimes not considering the merits of their case. And in politician mode, we don’t ACTUALLY change our minds, we just say that we do.


This is where the fourth mindset comes in: The Scientist. When we’re thinking like a scientist, we give little care about whether we’re right or wrong, we just want to know the truth. So, we form hypotheses, run experiments, and constantly update our views of the world (just like real scientists do). THIS is the mindset most conducive to individual rethinking and it’s what Adam Grant advocates for us to do more often.

The Dunning Kruger Effect

Another thing Grant mentions which encourages readers to rethink is the Dunning Kruger effect.

The Dunning Kruger effect is basically the idea that the more you know about a topic, the more you know that you actually know very little. Because of this, oftentimes people who are experts in subjects are actually LESS confident than people who only know very little of the subject.

If you have a hobby or sport or game that you’re a long time participant in, I encourage you to follow along with this mental exercise:

  • Think about when you first started your activity
  • How much did you think you know about it? Did you go in thinking it was going to be easy or hard?
  • Now think about your activity now
  • Have your thoughts changed?
  • What was true about what you originally thought? What was wrong?

Chances are, if you go through this exercise, you’ll find that you were really overconfident when you first started your activity. I know that this is definitely true for me and golf. When I first started golfing I was confused why everyone was having so much trouble getting this small little ball into the hole. Now, almost 14 years into the sport, I am no longer confused.


Being cognizant about the Dunning Kruger Effect will help you avoid being overconfident and also promote rethinking cycles. Grant makes a big point about not turning into an armchair quarterback and actively practicing what he calls “confident humility” where you’re confident in your ability to learn, but humble about what you actually know.

Identity Foreclosure

The final thing that really stuck out to me is Adam Grant’s thoughts on identity foreclosure. Rethinking applies to basic beliefs we hold about the world, AND to beliefs that we hold about our identity and our path in life. Identity foreclosure is when we make up our minds about who we are too early and “foreclose” on our identity, refusing to change our minds.

Grant tells a story about his cousin that really stuck out to me. The gist of it is this:

  • His cousin fell in love with the idea of becoming a neurosurgeon very early on (something his family really wanted him to do)
  • As the years went on and he committed more and more time to his career path (med school, internships, residency) he started realizing that he didn’t really want to be a surgeon
  • BUT, he never turned back because he had “already come this far”
  • Thus he kept pushing and grinding away at something he didn’t really love until 13 years into his neurosurgeon career he decided to quit and start an entrepreneurial venture
  • Looking back, he wished he had turned back way way earlier than he did

This is a classic tale of identity foreclosure. Where someone who initially chooses a career / sport / identity realizes it’s not for them, but don’t turn away because they feel like they’ll have “wasted” the time they spent.

Adam Grant puts it well when he states that “it’s better to have wasted 2 years than to go and waste 20 more.”


The idea of identity foreclosure and rethinking your own identity really stuck out to me because I’m at a crossroads in my life where I need to make decisions about my life and future. This section helped me take a closer look at my beliefs and pinpoint what exactly I’m clinging to and what I need to let go.

What I Loved About Think Again

I really loved how Adam Grant practices what he preaches throughout the book. In true scientist fashion, the book comes across as a set of hypotheses that Grant has meticulously tried and tested, but is not afraid to change his mind about.

In the epilogue of Think Again, Grant even brings up shortcomings of his own book! Not to mention, he does this while showing you the literal writing process for his conclusion.

If there’s one group of person that annoys me more than others, it’s hypocrites. Because of Grant’s approach, I was much more receptive to the ideas in his book.

And that brings me to the second thing I loved about Think Again. It helped me… think again! While reading the book I found myself questioning my own preconceived notions and beliefs. From political beliefs to everyday interactions to my own career path, this book has helped me keep an open mind and rethink the things I hold to be true. I am now one step closer to knowing what I don’t know…

What I Disagree With About Think Again

Not much! Adam Grant did an excellent job using his own advice so there aren’t too many flaws with his book. The only thing I would point out is the lack of coverage regarding the 4 mindsets. (This, however, is something that Grant himself points out too).

While the scientist mindset may be best for our own thinking, it might not be ideal certain scenarios. For example:

  • Preacher mode might be useful when trying to persuade a crowd
  • Prosecutor mode might be useful when thinking about the weaknesses in another’s argument
  • Politician mode might be good for short-term situations

The one that I’m noting especially is the preacher mode. If you survey all the great motivational speakers, they (almost) all come across as preachy. BUT, that doesn’t mean they aren’t effective. On the contrary, many of the best speakers in the world have firm and unwavering views. The same is true for persuasive leaders.

Perhaps the key is to practice being a scientist alone, but enter preacher mode when trying to persuade. That being said, I’m willing to rethink my book review of Think Again.

Think Again Review (Final Rating)

Book Review of Think Again
Book Review of Think Again

Think Again opened my eyes to just how little I know. For that I am both incredibly annoyed, yet also incredibly grateful.

This book is a must for anyone and everyone who hopes to succeed in today’s day and age. It can be a little bit dense in some sections, but all in all a great read. For changing the way that I think, while also practicing its own principles, I give Think Again by Adam Grant

4.5/5 Stars

The books on the docket for next month are:

  • Relentless: Mark Grover
  • The 4 Hour Work Week: Tim Ferriss
  • Anything else you suggest!

Feel free to suggest books in the comments and I’ll be sure to consider them for next month’s book review. Until then, check out more of my content on Financial Pupil and happy reading!

Thanks for reading through this Book Review of Think Again and thank you for following along! If you’re a Canadian Student, check out the Ultimate Canadian Student’s Guide to Personal Finance! To learn more about me, head over to this link here. If you want to get exclusive updates and tips, drop your email in the “get updates” box (might have to scroll up a bit.) Let me know your thoughts and suggestions in the comments!