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The Uncertainty Principle
An epic, breathtaking story of self-discovery, love, and adventure from New York Times bestselling author Joshua Davis and his son Kal Kini-Davis, perfect for fans of Nina LaCour and John Green.
Seventeen-year-old Mia is stranded in the middle of the Caribbean. After a mortifying incident in the school cafeteria, her parents decide there is only one way to deal with her move onto a battered sailboat and leave everything behind. Her mom and dad think it’s the best decision they’ve ever made. Mia feels like she’s been kidnapped and imprisoned in paradise with no internet and no destination.
Her only hope is to hack together a solar-powered satellite phone so she can call her best friend and fix everything. To do it, she’ll have to build a mobile laboratory on the boat and ignore her neurotic mother, who thinks Mia is falling apart.
The problem is, Mia is falling apart. By day, she scours deserted islands, looking for anything she can use to build the phone. At night, she squeezes into a narrow bunk and talks to an imaginary friend. She knows, with absolute certainty, that she needs to abandon her family to save her sanity.
And then two teenagers sail into her world, promising friendship, and maybe even romance. Thoughtful, soulful Alby was raised in Australia but now his family calls the sea their home. The only thing missing is his soulmate. Bold, beautiful Nisha is simply vacationing on her dad’s megayacht when a chance encounter upends her life.
Now—with everything hanging in the balance—Mia must decide who she is and what she wants. And with this decision comes the revelation that her past and future are more uncertain than she thought.
Seventeen-year-old Mia is stranded in the middle of the Caribbean. After a mortifying incident in the school cafeteria, her parents decide there is only one way to deal with her move onto a battered sailboat and leave everything behind. Her mom and dad think it’s the best decision they’ve ever made. Mia feels like she’s been kidnapped and imprisoned in paradise with no internet and no destination.
Her only hope is to hack together a solar-powered satellite phone so she can call her best friend and fix everything. To do it, she’ll have to build a mobile laboratory on the boat and ignore her neurotic mother, who thinks Mia is falling apart.
The problem is, Mia is falling apart. By day, she scours deserted islands, looking for anything she can use to build the phone. At night, she squeezes into a narrow bunk and talks to an imaginary friend. She knows, with absolute certainty, that she needs to abandon her family to save her sanity.
And then two teenagers sail into her world, promising friendship, and maybe even romance. Thoughtful, soulful Alby was raised in Australia but now his family calls the sea their home. The only thing missing is his soulmate. Bold, beautiful Nisha is simply vacationing on her dad’s megayacht when a chance encounter upends her life.
Now—with everything hanging in the balance—Mia must decide who she is and what she wants. And with this decision comes the revelation that her past and future are more uncertain than she thought.
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First published June 3, 2025
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About the author
Joshua Davis
71 books41 followersJoshua Davis is an American writer, film producer and co-founder of Epic Magazine.
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Displaying 1 - 30 of 33 reviews
May 17, 2025
Mia has never really understood how to act in social situations, but fortunately, her friend Sadie was there to coach her on ... well, how to hide some of her weirdness. Her weirdness being: Mia was always more interested in tech stuff, such as building solar panels, than in looking fashionable or following pop culture trends. Then, something happened in their friendship: Mia had a major meltdown at school and was quietly told not to return to class the following semester. Mia's parents took their derelict boat, left their lives in Minnesota, and went sailing from island to island in the Caribbean full-time. A dream life, some might say -but Mia feels deeply misunderstood and virtually kidnapped. She secretly works on building a satellite radio to try to call Sadie. And then, after months at sea without meeting anyone her age, she makes two new friends who would push her to discover new things about herself.
This was a pretty good exploration of neurodivergence and mental health struggles (Mia's mother), as well as universal adolescent themes of fitting in versus finding a group of people who will appreciate you for who you are. To me, Mia seemed quite obviously to be a low-support-needs autistic person, to the extent that the story seemed well-informed by how level-one ASD manifests in girls. I'm still wondering why the authors decided not to overtly identify her as autistic, missing the chance to give readers who find Mia's struggles relatable a valuable hint to look into this diagnosis.
It should be said that it's not easy to please me when it comes to how interactions between teens are portrayed in YA literature, so it means something that I quite liked how Mia's relationships with Alby and Nisha unfolded. Without giving too much away, there was this raw and genuine exploration of adolescent sexuality, as well as scenes reminiscent of best of Wilde's plays (you know, the ones where a character doesn't know who is secretly present in another room and then must adjust the truths they tell different people).
And, of course, hooray for the representation of women in science!
Publication date June 3, 2025.
Thanks to the publisher for providing me with an eARC through NetGalley. The opinion above is my own.
This was a pretty good exploration of neurodivergence and mental health struggles (Mia's mother), as well as universal adolescent themes of fitting in versus finding a group of people who will appreciate you for who you are. To me, Mia seemed quite obviously to be a low-support-needs autistic person, to the extent that the story seemed well-informed by how level-one ASD manifests in girls. I'm still wondering why the authors decided not to overtly identify her as autistic, missing the chance to give readers who find Mia's struggles relatable a valuable hint to look into this diagnosis.
It should be said that it's not easy to please me when it comes to how interactions between teens are portrayed in YA literature, so it means something that I quite liked how Mia's relationships with Alby and Nisha unfolded. Without giving too much away, there was this raw and genuine exploration of adolescent sexuality, as well as scenes reminiscent of best of Wilde's plays (you know, the ones where a character doesn't know who is secretly present in another room and then must adjust the truths they tell different people).
And, of course, hooray for the representation of women in science!
Publication date June 3, 2025.
Thanks to the publisher for providing me with an eARC through NetGalley. The opinion above is my own.
February 27, 2025
I had the chance to read an advanced copy from Netgalley.
Good book that kept my attention. The writing is beautiful - descriptive.
Good book that kept my attention. The writing is beautiful - descriptive.
July 11, 2025
Mia, who is possibly a genius and/or on the Asperger's spectrum, has no idea how to be the typical teenager her friend Sadie tried to mold her into. After a mortifying blowup in the school cafeteria, Mia is expelled, and her parents decide the only option--both for Mia, and her mother whose germophobia has skyrocketed since the Pandemic--is to leave land altogether and live on their small sailboat. It's been six months, they are in the Caribbean, and Mia can't stand it. Her mother is literally driving her crazy, there's no Internet, no phones, and no way to fix things. It's so bad that Mia's only companion is an imaginary physicist named Lena, and Mia spends all her time trying to build a satellite phone so she can call Sadie and figure out what happened--and how to fix it. Just as Mia decides that she has to get off the boat and they make plans for her to go live with her uncle in Tennessee, Mia meets two new kids her own age. Australian Alby and his family have been living on their boat for five years. He's a calm, gentle scholar of Judaism, and sees something in Mia that no one else has. Then there's Nisha, vacationing on her dad's megayacht, who sees even more about Mia than Mia ever guessed. Why is this all happening now?
I liked this one a lot. Great descriptions of the sea and the Caribbean, and the variety of people you meet there. Mia is a strong character, not sure if she's on the spectrum but she definitely thinks different than other people, which has made her life difficult. I liked her figuring out that she wasn't the problem, and that there were people in the world who would like her for who she is, divergent brain and all. I did get confused sometimes with all the names, since the author calls the parents by their first names, and it always took me a few minutes to remember who was who. Also I kept forgetting that Lena was imaginary, since Mia talked to her so much, so that was a bit distracting. Overall, though, a winner. Thanks to Libro.FM for a free educator copy of the audiobook.
I liked this one a lot. Great descriptions of the sea and the Caribbean, and the variety of people you meet there. Mia is a strong character, not sure if she's on the spectrum but she definitely thinks different than other people, which has made her life difficult. I liked her figuring out that she wasn't the problem, and that there were people in the world who would like her for who she is, divergent brain and all. I did get confused sometimes with all the names, since the author calls the parents by their first names, and it always took me a few minutes to remember who was who. Also I kept forgetting that Lena was imaginary, since Mia talked to her so much, so that was a bit distracting. Overall, though, a winner. Thanks to Libro.FM for a free educator copy of the audiobook.
October 12, 2025
Mia's life is nothing like anyone else's. After The Incident, her germophobic mom and fairly normal dad decided to try the sailing life on The Graceland. Now Mia lives on a 40 foot ship with her parents and younger brother, sailing the Caribbean. With no one her age around, Mia has turned to her imaginary friend, scientist and Harvard professor Lene, for company while trying to build a radio to talk to her friend, Sadie. The biggest issue is that Mia has no idea if Sadie wants to talk to her, especially after what happened.
When Mia's family collides with another sailing family, it seems that Alfy is everything she wanted. Then when the rich and beautiful Nisha comes into the picture, things get even more complicated. For Mia, she has to figure out what she wants for her future while dealing with demons from her past. That can make her feel like a small boat in a big ocean.
To review: Mia was the stereotypical angst teenager whose parents don't understand them and she doesn't want to make any decisions. If you can deal with those two things with your main character, you'll be okay. The plot was alright, not amazing. It was pretty introspective, of course, and Mia got a little overbearing at times. I did enjoy the idea that there are a bunch of people just sailing around the Caribbean- that wasn't something I'd thought of before. I did enjoy the closure with her mom, and with Sadie as well. It wasn't bad, but it certainly didn't blow me away.
When Mia's family collides with another sailing family, it seems that Alfy is everything she wanted. Then when the rich and beautiful Nisha comes into the picture, things get even more complicated. For Mia, she has to figure out what she wants for her future while dealing with demons from her past. That can make her feel like a small boat in a big ocean.
To review: Mia was the stereotypical angst teenager whose parents don't understand them and she doesn't want to make any decisions. If you can deal with those two things with your main character, you'll be okay. The plot was alright, not amazing. It was pretty introspective, of course, and Mia got a little overbearing at times. I did enjoy the idea that there are a bunch of people just sailing around the Caribbean- that wasn't something I'd thought of before. I did enjoy the closure with her mom, and with Sadie as well. It wasn't bad, but it certainly didn't blow me away.
July 1, 2025
Thank you NetGalley and Penguin Workshop for the eARC I received of this
One thing about me is I'l pick out something to read in a few weeks, forget what it's about, and then be completely shocked when I finally pick it up. So while I was pretty confused the first few chapters, I was absolutely delighted to find out that past me had set me up with a bisexual teenage adventure. Mia's journey to of discovery and acceptance - of more than just her sexuality - felt incredibly genuine and realistic for someone her age. I loved seeing her become more confident and allowing herself to feel and explore.
As some other reviewers have noted, it seems likely/obvious that Mia's mother has OCD and Mia is autistic, though the book doesn't confirm or explicitly name either of those things. While I understand how that might have felt hard to pull off with it being from Mia's POV, I do think it would be valuable for younger readers who might not be able to identify those traits as easily.
My biggest critique of this is that I felt the wrap up/ending was very sudden and too quick. One second we were leading up to the climax and the next the whole thing was over. I almost felt like I had accidentally skipped a few chapters. Despite that, I felt Mia and the cast of characters around her were charming enough to keep this a predominantly positive experience.
One thing about me is I'l pick out something to read in a few weeks, forget what it's about, and then be completely shocked when I finally pick it up. So while I was pretty confused the first few chapters, I was absolutely delighted to find out that past me had set me up with a bisexual teenage adventure. Mia's journey to of discovery and acceptance - of more than just her sexuality - felt incredibly genuine and realistic for someone her age. I loved seeing her become more confident and allowing herself to feel and explore.
As some other reviewers have noted, it seems likely/obvious that Mia's mother has OCD and Mia is autistic, though the book doesn't confirm or explicitly name either of those things. While I understand how that might have felt hard to pull off with it being from Mia's POV, I do think it would be valuable for younger readers who might not be able to identify those traits as easily.
My biggest critique of this is that I felt the wrap up/ending was very sudden and too quick. One second we were leading up to the climax and the next the whole thing was over. I almost felt like I had accidentally skipped a few chapters. Despite that, I felt Mia and the cast of characters around her were charming enough to keep this a predominantly positive experience.
June 5, 2025
4.25 ⭐️
A HUGE thank you to Penguin Teen for sending me a finished copy of this book! As a lover of character-driven, transformative stories, I truly enjoyed reading this book.
Our mc is 16 year-old Mia, and she has a lot going on. She has an intelligence unappreciated by her family and peers, a mother that’s a bit mentally unstable, and a friendship that’s ready to fall apart. After an incident that happens at school, her parents decide the best course of action is to take the entire family out to sea until who-knows-when. That is where we find Mia, stuck on a boat with her parents, little brother, and her new imaginary friend/award-winning female scientist.
There are many layers to this book. Our lonely Mia, desperate for companionship, suddenly makes two friends and is overwhelmed by bonds that may have formed too deeply - all of which happens as soon as she demands that her family let her go back to to mainland. With so much that is uncertain, Mia must figure out what she wants, and hopefully, who she is.
This phenomenal YA addresses it all: family, friendship, romance, mental illness, and, most importantly, self-love. At the end of the day, 𝘀𝗼𝗺𝗲𝘁𝗶𝗺𝗲𝘀 𝘆𝗼𝘂 𝗻𝗲𝗲𝗱 𝘁𝗼 𝗲𝗺𝗯𝗿𝗮𝗰𝗲 𝘁𝗵𝗲 𝘂𝗻𝗰𝗲𝗿𝘁𝗮𝗶𝗻𝘁𝘆.
A HUGE thank you to Penguin Teen for sending me a finished copy of this book! As a lover of character-driven, transformative stories, I truly enjoyed reading this book.
Our mc is 16 year-old Mia, and she has a lot going on. She has an intelligence unappreciated by her family and peers, a mother that’s a bit mentally unstable, and a friendship that’s ready to fall apart. After an incident that happens at school, her parents decide the best course of action is to take the entire family out to sea until who-knows-when. That is where we find Mia, stuck on a boat with her parents, little brother, and her new imaginary friend/award-winning female scientist.
There are many layers to this book. Our lonely Mia, desperate for companionship, suddenly makes two friends and is overwhelmed by bonds that may have formed too deeply - all of which happens as soon as she demands that her family let her go back to to mainland. With so much that is uncertain, Mia must figure out what she wants, and hopefully, who she is.
This phenomenal YA addresses it all: family, friendship, romance, mental illness, and, most importantly, self-love. At the end of the day, 𝘀𝗼𝗺𝗲𝘁𝗶𝗺𝗲𝘀 𝘆𝗼𝘂 𝗻𝗲𝗲𝗱 𝘁𝗼 𝗲𝗺𝗯𝗿𝗮𝗰𝗲 𝘁𝗵𝗲 𝘂𝗻𝗰𝗲𝗿𝘁𝗮𝗶𝗻𝘁𝘆.
June 18, 2025
After a mortifying incident in the school cafeteria, sixteen-year-old Mia is now standard on a battered sailboat with her family in the middle of the Caribbean. Her mom and dad believe that leaving everything behind is the best decision they’ve ever made, but Mia feels like she’s been kidnapped and imprisoned with no internet and no destination.
Her only hope is putting together a solar-powered satellite phone from scratch using salvaged parts so she can call her best friend and fix everything. By day, it’s island hopping. By night, Mia squeezes into a narrow bunk and talks to her imaginary friend, award-winning female scientist, Lene.
And then, two teenagers sail into Mia’s life, Alby and Nisha, promising friendship, and maybe even romance. Alby, who grew up in Australia, but now also sailing the world with his family, is thoughtful and kind. Nisha, who is vacationing on her dad’s megayacht and is bold and beautiful.
Now Mia has to decide to stay with her family or to go live with her Uncle in Tennessee.
I really enjoyed the writing and exploration of not only mental health with Mia’s mother and her OCD, but also Mia’s neurodivergence. To me, it was quite obvious that Mia was high(er) functioning autistic and I wish it was discussed or talked about more in the novel so readers could feel a bit more seen while reading. I think because of this, I was also reading Mia as younger than sixteen and felt more like she was thirteen/fourteen.
But, overall, I really enjoyed this novel. The relationships felt authentic as well as the exploration of sexuality. Things felt evenly paced and realistic time wise. Oh - and there’s amazing representation of women in STEM. I think both teen and adult readers could enjoy this novel.
*Thank you Penguin Workshop and NetGalley for a digital copy of this book in exchange for an honest review
Her only hope is putting together a solar-powered satellite phone from scratch using salvaged parts so she can call her best friend and fix everything. By day, it’s island hopping. By night, Mia squeezes into a narrow bunk and talks to her imaginary friend, award-winning female scientist, Lene.
And then, two teenagers sail into Mia’s life, Alby and Nisha, promising friendship, and maybe even romance. Alby, who grew up in Australia, but now also sailing the world with his family, is thoughtful and kind. Nisha, who is vacationing on her dad’s megayacht and is bold and beautiful.
Now Mia has to decide to stay with her family or to go live with her Uncle in Tennessee.
I really enjoyed the writing and exploration of not only mental health with Mia’s mother and her OCD, but also Mia’s neurodivergence. To me, it was quite obvious that Mia was high(er) functioning autistic and I wish it was discussed or talked about more in the novel so readers could feel a bit more seen while reading. I think because of this, I was also reading Mia as younger than sixteen and felt more like she was thirteen/fourteen.
But, overall, I really enjoyed this novel. The relationships felt authentic as well as the exploration of sexuality. Things felt evenly paced and realistic time wise. Oh - and there’s amazing representation of women in STEM. I think both teen and adult readers could enjoy this novel.
*Thank you Penguin Workshop and NetGalley for a digital copy of this book in exchange for an honest review
September 5, 2025
This book was an odd duck-just like the neurodivergent main character. Mia, a teenager, is “stuck” on a boat with her OCD germaphobe mom and her dad (who honestly just a blends in with the background) -and there’s a little brother I believe. Oh, and Mia has an imaginary friend , a Danish scientist, aboard as well. Mia’s family escapes on this ramshackle boat from Duluth after an embarrassing incident involving Mia at school (clearly she was disciplined without considering her disability-but the reader must suspend their disbelief.) Already, pretty implausible.
Mia is miserable on the boat as she strives to contact her friend on the mainland, struggles with the advice of the imaginary friend, battles her mom’s unreasonable germophobia, and later considers evolving relationships with two people she meets on the trip. I found the book unsatisfying and very hard to relate to.
Mia is miserable on the boat as she strives to contact her friend on the mainland, struggles with the advice of the imaginary friend, battles her mom’s unreasonable germophobia, and later considers evolving relationships with two people she meets on the trip. I found the book unsatisfying and very hard to relate to.
May 17, 2025
Thank you to PENGUIN GROUP Penguin Young Readers Group | Penguin Workshop and NetGalley for an electronic advanced readers copy of this novel.
Mia is sailing with her family, sort of aimlessly because her family is adrift in more ways than one. Her mother is a germaphobe unmoored by the pandemic and wants to keep her family safe. Mia threw food after a betrayal by her best friend. Isolated, Mia talks to her imaginary friend and works on her science projects.
Mia finally runs into people her age but it just leads to more confusion.
The Uncertainty Principle is an interesting tale of a troubled teenager trying to grow up in an unusual situation. I thought it was pretty well written but I had trouble relating.
Mia is sailing with her family, sort of aimlessly because her family is adrift in more ways than one. Her mother is a germaphobe unmoored by the pandemic and wants to keep her family safe. Mia threw food after a betrayal by her best friend. Isolated, Mia talks to her imaginary friend and works on her science projects.
Mia finally runs into people her age but it just leads to more confusion.
The Uncertainty Principle is an interesting tale of a troubled teenager trying to grow up in an unusual situation. I thought it was pretty well written but I had trouble relating.
June 7, 2025
For anyone, young or old, trying to figure their lives out, this book is a must. Teenagers especially will relate, but older folks will also gain insights. Do I want the lifestyle of the rich and famous, or those vagabonds, with no cares in the world? Do I want to hang out with boys or girls, or both? You’ll laugh, you’ll cry, but whatever you do, don’t miss this book. I loved it and couldn’t put it down. It’s a must read.
June 5, 2025
a beautiful journey of self discovery while being a teenager. I couldn’t put the book down. I related to Mia on so many levels and could not wait to she where her story went! the book offers so many intricate relationship dynamics between family, friends and romantic partners. a perfect book for the summer time!
June 14, 2025
I actually enjoyed this book. I often didn’t know where it was leading yet I was still feeling like I had to keep reading. My one and only complaint is I would have loved if it wrapped up more. And we had an ending where diagnosis was talked about. But maybe that’s a part of the appeal, we’ll never really know. Overall still really liked it though!
June 25, 2025
This book took a second to pull me in, but then I was hooked. Reading it as an adult, I found myself sympathizing the most with Mia’s mother and her struggles, and got frustrated with Mia’s refusal to even try understanding her mom. However, I appreciated Mia’s self discovery, and her brilliance in STEM. I liked watching her come into her own person.
(Thanks goodreads for the giveaway)
(Thanks goodreads for the giveaway)
July 5, 2025
This book definitely captured my attention. The main character was interesting and she and her mom were quite interesting characters. I do wish there were more scenes with the family and the event highlighted at the beginning (and was a clear build up) resulted in barely a few pages in the last 5% of the book.
August 28, 2025
at 32, this is a book I wish I could've gotten my hands on as a 17 year old. It's a an immersive story that navigates the in-betweens of emotional intelligence and intellectual intelligence, how the two can support each other, and...hinder each other. It's juicy, smart, niche, and delightfully educational.
September 1, 2025
Scintillating from start to finish, this book lit a fire in me. It left me not only inspired but empowered to make meaningful changes in my own life—to seek the depth of connection and adventure that this family so beautifully embraced. A truly moving and transformative read. Thank you for the inspiration
September 1, 2025
A beautiful and rollicking YA story that unfolds on the high seas. The Davises perfectly capture the angst of young love, the struggle to come into one's own, and the sexual fluidity of today's youth. Destined to be a modern classic.
September 24, 2025
An epic adventure! They should make this book into a movie - gorgeous settings, a compelling protagonist and supporting cast, and an uplifting story of what you gain when you learn to trust yourself. So full of heart and the joy of coming into one's own. I loved it and highly recommend.
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May 13, 2025Loved reading this book!
June 5, 2025
I loved this book! It is a great summer/beach read and captures the teenage experience very well. It's a fun read while also being interesting and exploring cool topics. Highly recommend!
June 6, 2025
An uplifting tale of adolescence populated by delightful neurospicy characters and set in a beautiful ocean paradise... a great summer read!
July 26, 2025
3.5 stars
A good finding-self YA consideration that does things in a different way. Considerations of sexual identity and autonomy/choice are central here.
A good finding-self YA consideration that does things in a different way. Considerations of sexual identity and autonomy/choice are central here.
September 1, 2025
Great read very engaging and a super interesting story
September 1, 2025
Great for young adults, and old adults who are young at heart. An important story at just the right time!
September 1, 2025
Another Joshua Davis page turner. While the novel was overall a good read, I absolutely loved the characters, they were written beautifully written and absolutely stole the show.
September 1, 2025
A very enjoyable read and full of adventure!
September 1, 2025
All the great elements of YA – the relationships, adventure, personal dilemma and growth but in a totally unexpected setting and with fresh interesting new characters. Great read and recommendation!
September 1, 2025
Accurate and poignant story about the interior life of an adolescent, in a unique and challenging setting, rendered vividly. That the authors are father and son make it even more lovely. Recommend!!
September 2, 2025
Heartfelt, engaging, unpretentious, and entertaining. Breezed through it with my kids (14 and 11) and they felt connected with the characters and it spurred some nice self-reflection.
September 2, 2025
My 17 year old daughter and I both read this - rare for us to both enjoy the same book
Displaying 1 - 30 of 33 reviews