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Very Short Introductions #684

Time: A Very Short Introduction

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What is time? What does it mean for time to pass? Is it possible to travel in time? What is the difference between the past and future? Until the work of Newton, these questions were purely topics of philosophical speculation. Since then we've learned a great deal about time, and its study has moved from a subject of philosophical reflection to instead became part of the subject matter of physics.

This Very Short Introduction introduces readers to the current physical understanding of the direction of time, from the Second Law of Thermodynamics to the emergence of complexity and life. Jenann Ismael charts the line of development in physical theory from Newton, via Einstein's Theory of Relativity, to the current day. Einstein's innovations led to a vision of time very different from the familiar time of everyday sense. In this new vision, time is one of the dimensions in which the universe is extended alongside the spatial dimensions. The universe appears as a static block of events, in which there is no more a difference between past and future than there is between east and west. Discussing the controversy and philosophical confusion which surrounded the reception of this new vision, Ismael also covers the contemporary mixture of statistical mechanics, cognitive science, and phenomenology that point the way to reconciling the familiar time of everyday sense with the vision of time presented in Einstein's theories.

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144 pages, Paperback

Published January 3, 2022

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357 people want to read

About the author

Jenann Ismael

5 books24 followers
Jenann Ismael is Professor of Philosophy at the Columbia University. She received her M.A. and Ph.D. from Princeton. Her areas of specialization are philosophy of physics, metaphysics, philosophy of science and the philosophy of mind.
She has held fellowships from the Mellon Foundation, the NEH, Templeton, the National Humanities Center, and Stanford’s Center for Advanced Study in the Behavioral Sciences (CASBS).

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Displaying 1 - 30 of 30 reviews
Profile Image for Brandon Stariha.
48 reviews2 followers
June 17, 2022
A must read for anyone interested in time. JenAnn Ismael, a Philosopher with a specialty in philosophy of physics, philosophy of science and Metaphysics starts by giving a run down of the history of the concept of time. Starting with the earliest philosophers to Newton, then Newton to Einstein and explains in a approachable way exactly what is different about Time in Einstein’s theories.

Making the concept of time as a fourth dimension a lot more intuitive.

Up until this point, it may be just a mere catch up for people who study physics but after the set up, she spends most of the rest of the book discussion the philosophical implications of relativity and the tension between time as humans experience it and the physicists time.

It’s this later portion of the book that I think everyone could be interested in and is important to all.

In fact, she describes time and human experience in a way near the end, that had brought me to tears because of how beautiful and conceptually illuminating it was.

It’s hard to put Into words but here’s an analogy. To the Kantian understanding of the value of humans i.e. Dignity, humans have a value of absolute value. Not a numerical value. It’s one thing to live the life believing that, acting like you believe it. But when it really and I mean really clicks and you understand exactly why humans have dignity, it’s something that you are aware of but now you grasp it fundamentally and it’s so beautifull and powerful that it brings you to tears to understand why humans have an absolute worth.

She does this with the human experience of time, something I clearly get and experience and live but in the way she breaks things down then builds it back to to explain a phenomenon of a doctor being impatient with a one’s mother. Despite both of you at that moment seeing the same body, you have the experience of time with her and so you see far more than what the doctor sees.

My explanation doesn’t do it justice and perhaps I am overhyping it.

Regardless, it was a great intro to Time.
2 reviews2 followers
February 9, 2022
It might have been better to call this book 'The Metaphysics of Time: A Very Short Introduction'. Other readers seem to have been disappointed that it doesn't mention the history of clocks – or different cultural, mythical or literary treatments of time. Instead, it is a book about the *nature* of time. What is the metaphysical structure that underpins relationships like past/future and earlier/later? Ismael is thoroughly successful at addressing this question.

The first three-quarters of the book examines time as it's described by physics. This is the correct place to look for answers about the nature of time, and the answers can be counterintuitive. Ismael often reminds us that physics has the power to override our pre-scientific intuitions.

The last quarter of the book discusses time as it is experienced by humans. Ismael does a wonderful job of connecting physics with experience. She writes evocatively about music, memories and relationships – with vivid images of hiking and basketball, letters and restaurants – parents caring for young children and then children caring for elderly parents.

Ismael unites these two lenses: the nature of time as described by physics, and the nature of time as experienced by humans. It's the same question – about the metaphysical structure of time – addressed from different perspectives. Ismael's treatment of time might have been sterile, since it relies so heavily on physics, but her aim is to account for the structuring of events that we experience.

'What physics tells us about time, if it is correct, has to answer ultimately to our own experience.' (p.81)

Some of the material is unavoidably complex, but the metaphysical nature of time is unavoidably complex. And we don't fully understand it yet. Ismael highlights the strengths and gaps in our knowledge.
Profile Image for Kevin.
166 reviews7 followers
April 10, 2023
I’ve read a lot of VSI books. This was the best but it was not what I was expecting at all.

I was expecting clocks and train timetables and timekeeping. This book is about Newton and Einstein and spacetime and thermodynamics and philosophy of mind and the human spirit. It's a beautiful book about how time shapes our universe and our lives.

Chapter 1:
In the beginning, every polis had its own way of keeping track of time and they all reset to zero every time the king died. One day, the Seleucids decided not to reset their calendar and everyone agreed to use the same calendar forever more.

That’s all the book has to say about timekeeping. The rest is physics and philosophy.

Aristotle divided the heavens from the earth and they were each made from different stuff. The universe is finite with us at the centre.

In Newton’s universe, space is infinite and has no centre. Everything everywhere is made of the same stuff and follows the same laws. Motion is a change of place over time. Time and space exist independently of the objects that are in them.

Leibniz disagreed. Space and time are relations between objects.

Galileo showed that any experiment you might do at rest will get the same result if you are moving at constant velocity but this no longer holds if you are accelerating.

Chapter 2:
The speed of light is the same for everyone however fast they are travelling. Einstein’s special theory of relativity explains this by treating time as just another dimension in spacetime. Distances and time intervals are different for different observers. It makes no sense to say that one event in spacetime happened before or after another event at a different location or that one person is moving while another is at rest. It’s all relative to the observer.

Minkowski gave us the maths to describe spacetime. The general theory of relativity describes how spacetime is warped by massive objects. We get black holes where time appears to stop. But it doesn't.

Chapter 3:
Our commonsense understanding of time conflicts with the consequences of relativity. Philosophy!

Chapter 4:
All of the equations that describe the physical world are reversible. If you throw a ball, it will travel in a parabola. If you reverse time, it will follow the same trajectory in the other direction and physical equations have no opinion on which direction the clocks run. All physical equations except one, that is. The second law of thermodynamics says that you can't unstir your coffee.

The book describes the second law in terms of microstates and macrostates. Microstates (the organisation of the molecules of milk and coffee) don't care about the arrow of time. Macrostates (cups of coffee) do. If you keep track of all the microstates, there are more ways to arrange the molecules if the milk and coffee are mixed than if they are kept separate. Macrostates that correspond to many microstate configurations are said to have higher entropy and stirred coffee stays stirred. The same rule applies to omelettes, steam engines and star systems. Any random change to the microstates is likely to result in greater entropy and time's river flows to the sea.

Given enough time and enough randomness, complex structures form spontaneously and some become stable. Some structures find a way to copy themselves and the machinery of life whirs into action. Throw in some occasional random mutations and a way to select for the best ones and evolution finds a way to swim upstream.

With life comes information. Life uses energy from the environment to change the environment for its own benefit and the lifeforms which are best able to record and process and utilise information about how to accumulate nutrients such as sunlight, cabbages or gazelles gain a survival advantage.

Information is recorded in DNA and neurons and cultures and the available information increases as organisms and societies grow more sophisticated. The organisms that use information most effectively come to dominate the world.

Chapter 5:
Einstein's world appears to show time as an illusion.

All of spacetime was laid out in advance and we seem to be travelling across it in a predefined route. But we humans don't experience time this way. Bergson argued that Einstein's world leaves out all the features of time that are essential to human understanding and time is more like a river that flows with a past, a present and a future.

Where is our sense of self in Einstein's world? What happened to that little boy who gazed up at the stars? Did that little boy become the man typing a book review in Goodreads? Philosophical mysteries abound.

Neuroscience sheds light on some of these mysteries. The unconscious brain performs amazing tricks with the data from our senses. It builds a model of the world informed by our memories and experiences and presents it to our consciousness. Our experience of the flow of time informs our model and guides our actions. It tells us where to run to return a tennis serve and when to hide our nuts in storage for the coming winter and it helps us to keep our memories in order.

We see our own lives from multiple perspectives. We live in anticipation, in experience and in remembering and our whole collection of memories, perceptions, hopes and fears shapes who we become. We look forward to branching possibilities and look back on the thin, hard line of fact.

The author becomes lyrical in chapter 5 and muses on penguins recognising their sole chick in a sea of thousands and struggling with third-grade maths. On the doctor who does not see, in the old woman on his operating table, the young mother who fastened our buttons against the cold on the first day of school. I thought I was reading a book about time but it turned out to be about all of the creation and all of humanity.

I wish all science books and philosophy books could be written this way. I will read it again and again.
Profile Image for Boolia Bart .
348 reviews1 follower
June 10, 2025
One thing that's always nice about the VSI books is that they leave me feeling dumb and that's a gift. This one in particular.
Profile Image for Harry.
89 reviews1 follower
December 16, 2021
The problem with complicated concepts such as space and time is that few people in this universe really understands deeply. Unfortunately, the author isn't one of them.
Profile Image for Carla Remy.
1,042 reviews112 followers
August 26, 2024
Physics, Newton, Time, Einstein…. This history of the way humans made time is so interesting but I am just not smart enough… Maybe someday.
Profile Image for Almudena.
Author 2 books32 followers
August 19, 2023
Interesante: la reflexión sobre la geometría del espacio tiempo (y los debates que generó) y su explicación del concepto de "distancia" en el contexto de la teoría de la relatividad general.
Profile Image for K. Nicholas Forti.
1 review
June 7, 2022
This book is an excellent “very short” introduction to the issues with which a Philosophy of Time will have to grapple in the wake of Einstein’s Theories of Special and General Relativity and the correlative SpaceTime Geometry of Hermann Minkowski. These include the relation of the Block Universe of SpaceTime to the Entropic Arrow of Time and to the conscious experience of the flow of time. Unfortunately, the author doesn’t address pre-Relativity Philosophies of time, such as those of Plato, Augustine, and Boethius. Neither does the author engage more modern Philosophies of Time, such as the Process Philosophy of A. N. Whitehead (though Einstein’s debate with Henri Bergson does get a mention). However, the intentionally brief and limited nature of these “Very Short Introduction” books precludes broad and deep engagement of all or even several aspect of the topic. The author has chosen to focus on an introduction to a modern Philosophy of Time as informed by the science of our day. In this limited scope and effort, the book succeeds. Based on the other reviews here, it seems that many of the readers simply weren’t expecting (and weren’t prepared to work through) a scientifically informed, modern Philosophy of Time. I suspect that many who have this book a poor review were, in fact, expecting the kind of content found in The History of Time: A Very Short Introduction by Leofranc Holford-Stevens. But this book should not be judged negatively for not being that book.
Profile Image for Desollado .
263 reviews5 followers
January 29, 2025
I'm a dedicated follower of this series, finding it an excellent resource for understanding complex subjects. However, I encountered a couple of titles that fell short of my expectations: "Time" and "Nothing."

I believe these books become somewhat disingenuous, as their concise titles suggest a more profound philosophical approach. For instance, "Nothing" – while the concept of nothingness is explored – seems to treat it more as a byproduct of other investigations. Similarly, "Time" delves more into the current scientific understanding of time than I anticipated.

For a richer approach that masterfully integrates social, philosophical, and scientific perspectives, I recommend "The Arrow of Time" by Carlo Rovelli. It's an exceptionally well-written book that offers a far deeper exploration of the subject.

This book is well-written, but I believe it falls short in its treatment of the subject matter.
Profile Image for Keith.
876 reviews12 followers
July 15, 2024
This Very Short Introduction (VSI) delves into the concept of time using physics and philosophy. Jenann Ismael spends the first portion explaining how Isaac Newton., Albert Einstein, and other scientists fundamentally changed mankind’s relationship with time, then spends the rest of the book going into the metaphysical implications of relativity and other theories on the human relationship with time. If this sounds complicated, that is because it is. I’ll admit that I struggled with Time and am unsure if I truly understood what Ismael had to say. I wish she could have ended each chapter in a textbook manner, providing a summary of the ideas for easier comprehension for laymen such as me. Perhaps this was not possible given the length limitation of Oxford’s VSI series. The book has given me a taste of these ideas, with Ismael kindly providing a list of books and articles at the end for further study.

QUOTES:
“Time itself is just one dimension of a four-dimensional manifold of events.” (p. xv).
*
“Space and time are not themselves observable. And if there are certain kinds of imagined transformations that one could make—either to the world as a whole, or to a system of objects in the world—without detection, we don’t have a good reason for believing that those transformations change anything physically real.” (p. 14).
*
“...once we have the new framework [relativity], we are left to assimilate it philosophically and Einstein’s innovations did such violence to fundamental pieces of common sense that, as we will see in chapters to come, we are still coping with the fallout.” (p. 25).
*
“Einstein showed us how to put Newtonian mechanics and electromagnetism together in a way that accommodated the observed constancy of the speed of light, and the result was completely transformative of our understanding of time.” (p. 34).
*
“According to Einstein’s theory there is no such thing as gravity. All objects in space follow the straightest trajectories that are possible, but space itself is curved by the presence of matter so that objects following straight-line trajectories accelerate. As the physicist John Wheeler succinctly put it: ‘Spacetime tells matter how to move; matter tells spacetime how to curve.’” (p. 39).
*
“Not many years ago, the gap between the familiar time of everyday sense and time as it appears in the relativistic image seemed unbridgeable. I think that is no longer true.” (p. 81).

************************************************************************

[Image: Book Cover]

Citation:
Ismael, J. (2021). Time: A very short introduction. OUP Oxford. https://www.amazon.com/gp/product/B09...

Title: Time: A Very Short Introduction
Author(s): Jenann Ismael
Series: Oxford Very Short Introductions #684
Year: 2021
Genre: Nonfiction - Physics & philosophy
Page count: 144 pages
Date(s) read: 7/11/24 - 7/12/24
Book # 138 in 2024
**
Profile Image for Uriel Aceves.
40 reviews1 follower
January 22, 2022
Disclaimer: I studied physics

It really feels like the author does know what she talks about but she doesn't understand anything about it, and this lack of understanding is replaced by cumbersome, obscure, messy and terrible writing.

The author claims to discuss the development of time from Newton to Einstein. By chapter 2 you are already at Einstein's era. But why start with Newton at all? Is there nothing to say before Newton? How did we come up with minutes of 60 seconds, hours of 60 minutes, and so on. No civilization used time before Newton?

The train of thought of the author is so bad that sometimes you read several pages without knowing where are they leading, or what's the point of them. And more often than not, when you figure out what was the point, you realize that the text was just going in circles, rambling around something that could have been clarified in one sentence. Most of the examples and analogies used to illustrate some concepts are terrible, and unnecessary. For instance, there is a boat example where she goes around with a poorly written and confusing example just to say "if A and B are moving they will have a different record or perception about which events are simultaneous".
Profile Image for Semih.
111 reviews
July 26, 2025
"Spacetime tells matter how to move; matter tells spacetime how to curve"

Yazarın bir felsefeci olması sebebiyle kitabın içerisindeki fiziğin popüler fizikten çok öteye geçememesi biraz hayal kırıklığına uğrattı. Zamanda yolculuk mekanizmasının işlendiği kısım her ne kadar heyecan yaratsa da klasik özel ve genel görelilik anlatımlarına bir açılım sağlamadı. Okuması eğlenceli ama yeni fikirlere dair düşündürmüyor. 'Further Reeadings' kısmındaki kitaplara baktığımda birkaç kitap radarıma takıldı.
Tarihçe üzerine 'Einstein's Clocks, Poincare's Maps: Empire of Time uzun snelerdir elimde olan bir kitap. Okumaya başlayabilirim ama şu aralar tarihçeden ziyade işin fiziği ile ilgilenmek istiyorum.
'A Brief History of Time' her ne kadar bir klasik olsa da Hawking'in dilini kolay bulmuyorum ama yeinden okumayı uzundur bekliyordum. Bu kitapla beraber lisede okuyup anlamakta çok zorlandığım bir başka kitap Richard Gott 'Time Travel in Einstein's Universe'. Barbour, Lockwood, Maudlin ve Price'ın kitaplarına da bakacağım farklı bakış açıları için.
Profile Image for Hanneke.
172 reviews2 followers
November 7, 2023
Obviously the concepts in this book are incredibly abstract and hard to grasp, but I found this book less illuminating than I had hoped. What is space time exactly? How do the four dimensions relate to each other exactly? What is the difference between general and special relativity? And why is quantum mechanics and behavior as the new horizon of physics and philosophy not explained?

I did thoroughly enjoy the chapter in which Ismael contextualises human experiences of time in the principles of entropy. Foregrounding the workings of memory to explain why people explain time the way they do. Really cool!
Profile Image for Gagandeep  Singh.
26 reviews18 followers
January 6, 2023
This is too boring.
The concept of time, space and spacetime is really exciting but needs to be handled in a very delicate albeit silly way so that someone like me who has only highschool level understanding of physics can both understand and appreciate. Sadly this book fails to do so even though it promises to deliver in its preface.

I tried to keep reading because I didn't want my first book of 2023 be dnf-ed but I am not gonna waste my time with something i know for sure I am not gonna enjoy.

Gotta get back to some good fiction!
Profile Image for John Sperling.
166 reviews8 followers
February 25, 2024
Interesting, albeit short, introduction to the concept of time that attempts to bridge the gap between common understandings of time and Einstein's theories. One drawback to the audio version is that you can't see the numerous figures and diagrams referenced in the text.

Ismael says that time...according to physics, does not pass or unfold, or come with any built in asymmetry. "There is no more difference between past and future than there is between east and west."
Profile Image for Edoardo Albert.
Author 54 books153 followers
November 19, 2024
As none of us have much of it, let's cut to the marrow: this is a book about time as understood through the equations of special and general relativity. So it's to do with frames of reference, the speed of light, and lines of causation. It's not a philosophical history of time, still less a mythical or religious view. But if you want a clear and concise formulation of what Einstein's equations tell us about time within the constraints of relativity, then this is your book.
Profile Image for Linda Is on her way.
213 reviews1 follower
September 26, 2024
I listened to roughly 15%
I don't remember one single thing she said and I don't know what any of it meant. I wouldn't recommend it to people with not much prior knowledge, like myself. I sat there questioning my English ability. It could've been in Chinese and I would've taken the same thing away from it. I'm too dumb for this and didn't pay attention in physics class
Profile Image for Zachary Littrell.
Author 2 books1 follower
March 11, 2022
Meh. Just didn't jazz me and kinda impatient for it to end. I didn't walk away with a much better idea of the arguments than before. A lotta fluff for a tiny book that kinda circles around "Gosh, well, time is complicated and you have to get used to it I reckon."
Profile Image for cypher.
1,525 reviews
October 17, 2024
such a complex subject...not sure this was the best version of a short explanation, for people who are trying to understand something from scratch, at least roughly...it does try to explain a lot things simply enough, though.
the intention of the collection is nice, overall.
Profile Image for Yasser Maniram.
1,340 reviews3 followers
January 7, 2022
Thought provoking although some of those thoughts are so abstract and relative to a concept that is lucid that it really makes you think.
Profile Image for josh fong.
6 reviews1 follower
May 22, 2022
First book ive bought since elementary school and the author had no idea what they were talking about.
Profile Image for Kat Rahmat.
23 reviews
November 5, 2022
A bit clumsily written but it is a difficult subject to try to encapsulate in an accessible and brief way.
Profile Image for Document Of Books.
156 reviews4 followers
December 8, 2024
A very concise and informative book about time. It has helped me understand the rift between Newtonian laws of physics and Quantum mechanics laws of physics. Fascinating!
Displaying 1 - 30 of 30 reviews

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