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The MIT Press Essential Knowledge
Understanding Beliefs
What beliefs are, what they do for us, how we come to hold them, and how to evaluate them. Our beliefs constitute a large part of our knowledge of the world. We have beliefs about objects, about culture, about the past, and about the future. We have beliefs about other people, and we believe that they have beliefs as well. We use beliefs to predict, to explain, to create, to console, to entertain. Some of our beliefs we call theories, and we are extraordinarily creative at constructing them. Theories of quantum mechanics, evolution, and relativity are examples. But so are theories about astrology, alien abduction, guardian angels, and reincarnation. All are products (with varying degrees of credibility) of fertile minds trying to find explanations for observed phenomena. In this book, Nils Nilsson examines beliefs: what they do for us, how we come to hold them, and how to evaluate them. We should evaluate our beliefs carefully, Nilsson points out, because they influence so many of our actions and decisions.
Some of our beliefs are more strongly held than others, but all should be considered tentative and changeable. Nilsson shows that beliefs can be quantified by probability, and he describes networks of beliefs in which the probabilities of some beliefs affect the probabilities of others. He argues that we can evaluate our beliefs by adapting some of the practices of the scientific method and by consulting expert opinion. And he warns us about "belief traps"--holding onto beliefs that wouldn't survive critical evaluation. The best way to escape belief traps, he writes, is to expose our beliefs to the reasoned criticism of others.
Some of our beliefs are more strongly held than others, but all should be considered tentative and changeable. Nilsson shows that beliefs can be quantified by probability, and he describes networks of beliefs in which the probabilities of some beliefs affect the probabilities of others. He argues that we can evaluate our beliefs by adapting some of the practices of the scientific method and by consulting expert opinion. And he warns us about "belief traps"--holding onto beliefs that wouldn't survive critical evaluation. The best way to escape belief traps, he writes, is to expose our beliefs to the reasoned criticism of others.
168 pages, Paperback
First published January 1, 2014
46 people are currently reading
664 people want to read
About the author
Nils J. Nilsson
29 books15 followersNils J. Nilsson is Kumagai Professor of Engineering, Emeritus, in the Department of Computer Science at Stanford University. He is the author of The Quest for Artificial Intelligence: A History of Ideas and Achievements and other books. He lives in Oregon.
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Displaying 1 - 30 of 31 reviews
April 12, 2015
Don’t misunderstand this book’s title. Nils Nilsson, an engineer and artificial intelligence specialist, isn’t interested in how we usually understand “beliefs,” which may mean religious convictions, opinions held without ironclad evidence, or partisan loyalties. Rather, Nilsson focuses on how we know concepts. While philosophers debate how we comprehend processes—riding a bike, speaking our native tongue, whatever—Nilsson questions how we know facts.
Nilsson begins with the premise that we cannot know very much directly. We devise a schema of the world around us based on evidence, testimony, and supposition, then assume this as our belief. This may involve how we believe (or disbelieve) scientific phenomena, like global warming, or how we believe society functions, or how past experience is relevant to current circumstances. Nilsson describes the ways we construct beliefs from limited evidence, and explain the entire world through partial glimpses.
Vernacular attitudes, Nilsson acknowledges, often receive “beliefs” as less solid or less worthy than “facts.” Nilsson quotes a friend saying “I don’t believe it, I know it,” as though belief is flimsy. Yet as Nilsson persuasively demonstrates, we actually know very little about the world, in the sense of having incontrovertible proof. It’s not possible to know, for instance, the contents of other people’s minds, or the behavior of forces we cannot sense, or the span of history from before our births to after our deaths.
That’s just a sample of the limits Nilsson puts on “knowledge.” We know very little directly. Consider how we know about social structures. We have sensory evidence about how people behave around us. But what about people far away, or people unlike ourselves? We have only the testimony of narratives, statistics, and other people’s stories. We mix our experience with others’ testimonies, draw conclusions, and apply them outward from there. These conclusions aren’t “facts,” no matter how virulently paid pundits ballyhoo them. They are beliefs.
Anyone who’s ever sat next to a three-year-old, though, knows the question that follows from any belief: “Why?” Individual beliefs we may hold, which we could structure as declarative statements ( i.e. “Markets will correct for shortages of supply”) are generally buttressed by supporting beliefs (“Prices reflect both supply and demand”). Nilsson describes complex belief networks, such as Bayesian belief networks, that describe ways humans support what they believe by increasing degrees of complexity.
Beliefs, in Nilsson’s formulation, should always be held lightly. We may believe Principle X, but we should always remain willing to test our beliefs against new, countervailing evidence. This means we should communicate with people who don’t share our beliefs, and should prize the belief-making process more highly than maintaining intellectual constancy. He admits this is easier said than done. However, we can regard certain tests and their outcomes as legitimating the processes of belief.
In advancing this claim, Nilsson includes the lengthiest, most complete description I’ve yet read of the scientific method. Whereas my high school teachers presented a simple four-step process of hypothesis, experiment, conclusion, and repetition, Nilsson describes a complicated process that is intensely social, cumulative in detail, and exuberantly sloppy. Though it isn’t nearly as dispassionate as schoolteachers might present, scientific method permits us to conduct reliable, repeatable tests to verify and refine our beliefs.
I must dispute one statement. Nilsson asserts that beliefs which we cannot subject to scientific scrutiny have no practical value and should be discarded. He means belief in transcendence and the supernatural, but this gives me pause. After all, what scientific scrutiny tells us that democracy is better than totalitarianism? Capitalism better than communism? Historical outcomes aren’t experimental results, especially since they can’t be retried. We all hold many beliefs that defy exacting scientific scrutiny.
Indeed, I’m not the first to observe that belief in scientific reliability is itself not scientific. Nilsson and I may agree that science provides reliable indicators about our physical world, and that drawing conclusions about tangible reality from evidence is better than drawing it from ancient testament. However, science provides spotty foundation for, say, managing your marriage, or raising your children, because impersonal forces differ from relationships. I believe in science. I also believe in its limits.
That quibble notwithstanding, Nilsson’s exposition on how humans know what we know is very illuminating. As a primer on scientific epistemology, it helps us make decisions about how we treat the knowledge we have, how we revise it, and how we defend or discard would-be facts. I’d recommend this text to schoolchildren worldwide, because we need more adults who know how they know.
Nilsson begins with the premise that we cannot know very much directly. We devise a schema of the world around us based on evidence, testimony, and supposition, then assume this as our belief. This may involve how we believe (or disbelieve) scientific phenomena, like global warming, or how we believe society functions, or how past experience is relevant to current circumstances. Nilsson describes the ways we construct beliefs from limited evidence, and explain the entire world through partial glimpses.
Vernacular attitudes, Nilsson acknowledges, often receive “beliefs” as less solid or less worthy than “facts.” Nilsson quotes a friend saying “I don’t believe it, I know it,” as though belief is flimsy. Yet as Nilsson persuasively demonstrates, we actually know very little about the world, in the sense of having incontrovertible proof. It’s not possible to know, for instance, the contents of other people’s minds, or the behavior of forces we cannot sense, or the span of history from before our births to after our deaths.
That’s just a sample of the limits Nilsson puts on “knowledge.” We know very little directly. Consider how we know about social structures. We have sensory evidence about how people behave around us. But what about people far away, or people unlike ourselves? We have only the testimony of narratives, statistics, and other people’s stories. We mix our experience with others’ testimonies, draw conclusions, and apply them outward from there. These conclusions aren’t “facts,” no matter how virulently paid pundits ballyhoo them. They are beliefs.
Anyone who’s ever sat next to a three-year-old, though, knows the question that follows from any belief: “Why?” Individual beliefs we may hold, which we could structure as declarative statements ( i.e. “Markets will correct for shortages of supply”) are generally buttressed by supporting beliefs (“Prices reflect both supply and demand”). Nilsson describes complex belief networks, such as Bayesian belief networks, that describe ways humans support what they believe by increasing degrees of complexity.
Beliefs, in Nilsson’s formulation, should always be held lightly. We may believe Principle X, but we should always remain willing to test our beliefs against new, countervailing evidence. This means we should communicate with people who don’t share our beliefs, and should prize the belief-making process more highly than maintaining intellectual constancy. He admits this is easier said than done. However, we can regard certain tests and their outcomes as legitimating the processes of belief.
In advancing this claim, Nilsson includes the lengthiest, most complete description I’ve yet read of the scientific method. Whereas my high school teachers presented a simple four-step process of hypothesis, experiment, conclusion, and repetition, Nilsson describes a complicated process that is intensely social, cumulative in detail, and exuberantly sloppy. Though it isn’t nearly as dispassionate as schoolteachers might present, scientific method permits us to conduct reliable, repeatable tests to verify and refine our beliefs.
I must dispute one statement. Nilsson asserts that beliefs which we cannot subject to scientific scrutiny have no practical value and should be discarded. He means belief in transcendence and the supernatural, but this gives me pause. After all, what scientific scrutiny tells us that democracy is better than totalitarianism? Capitalism better than communism? Historical outcomes aren’t experimental results, especially since they can’t be retried. We all hold many beliefs that defy exacting scientific scrutiny.
Indeed, I’m not the first to observe that belief in scientific reliability is itself not scientific. Nilsson and I may agree that science provides reliable indicators about our physical world, and that drawing conclusions about tangible reality from evidence is better than drawing it from ancient testament. However, science provides spotty foundation for, say, managing your marriage, or raising your children, because impersonal forces differ from relationships. I believe in science. I also believe in its limits.
That quibble notwithstanding, Nilsson’s exposition on how humans know what we know is very illuminating. As a primer on scientific epistemology, it helps us make decisions about how we treat the knowledge we have, how we revise it, and how we defend or discard would-be facts. I’d recommend this text to schoolchildren worldwide, because we need more adults who know how they know.
November 13, 2015
Good book; not great, but good. Here’s my take-away. We never experience reality directly – it is too big and too complex. Hence we can never “know” reality. Instead, based on limited information that comes to us through our limited experiences and sensory perceptions (including what we may read or hear from other people), we form models or mental constructions of reality. We call these mental constructions “beliefs.” These models help us make predictions about the world and choose our actions. The better our models of reality, the better we will be able to function in the world.
Beliefs have two different dimensions: (a) how well these models represent and help us cope with the real world (i.e., accuracy and credibility), and (b) how certain we are about the model (i.e., the strength of our belief). The distinction between beliefs and what we call knowledge is only a matter of degree, not a difference in kind. The strength of our beliefs is not necessarily an indicator of accuracy or credibility; we can believe strongly in something that may not be accurate or credible, and we can have an accurate belief about which we may remain uncertain or wavering. The former is much more common.
In addition to being limited, many of our perceptions are prone-to error. (There are many fine books about brain bugs, the limits of our rationality, and heuristics - mental shortcuts – that help us form quick decisions or judgments.) Some people also think there are extrasensory ways of perceiving truths. The best way to ensure a belief is sound or credible, says the author, is to apply critical thinking. This means checking not just information that could confirm your belief, but information that could disconfirm it. If information can be disconfirmed through testing or logic, you must be prepared to discard that belief (or element of the belief). The scientific method is the best approach yet devised to evaluate the accuracy and credibility of a belief – i.e., knowledge. Seek the opinion of experts. Consider the consequences of and explanation for our beliefs. And use the scientific method – predict, observe, test, explain. Evaluate the credibility of a statement. See if different pieces of your belief(s) are internally consistent. Our knowledge will never be absolute – it will always be subject to revision as more data is collected, more hypotheses are tested, etc.
Beliefs have two different dimensions: (a) how well these models represent and help us cope with the real world (i.e., accuracy and credibility), and (b) how certain we are about the model (i.e., the strength of our belief). The distinction between beliefs and what we call knowledge is only a matter of degree, not a difference in kind. The strength of our beliefs is not necessarily an indicator of accuracy or credibility; we can believe strongly in something that may not be accurate or credible, and we can have an accurate belief about which we may remain uncertain or wavering. The former is much more common.
In addition to being limited, many of our perceptions are prone-to error. (There are many fine books about brain bugs, the limits of our rationality, and heuristics - mental shortcuts – that help us form quick decisions or judgments.) Some people also think there are extrasensory ways of perceiving truths. The best way to ensure a belief is sound or credible, says the author, is to apply critical thinking. This means checking not just information that could confirm your belief, but information that could disconfirm it. If information can be disconfirmed through testing or logic, you must be prepared to discard that belief (or element of the belief). The scientific method is the best approach yet devised to evaluate the accuracy and credibility of a belief – i.e., knowledge. Seek the opinion of experts. Consider the consequences of and explanation for our beliefs. And use the scientific method – predict, observe, test, explain. Evaluate the credibility of a statement. See if different pieces of your belief(s) are internally consistent. Our knowledge will never be absolute – it will always be subject to revision as more data is collected, more hypotheses are tested, etc.
July 1, 2019
I liked a few brief analogies given by Nils. The first one was how beliefs tend to be like clothing, many people simply wear what they have to wear, some wear clothing to be fashionable, or to be comfortable, or to reveal their authority.
The other, in light of the Kantian idea (he doesn't however mention Kant) that though reality exist, we cannot directly know it as it is, but only our perception of it, he mentioned how our beliefs, are like the pilot's trust of the instruments of realities he isn't directly privy to. It is important that the meters and gauges to be well tested and accurate, less he fly into a mountain or enter a nose-dive, so we should be careful about the beliefs we adopt.
Nils seemed to be a naturalist and believes science to be the only avenue towards any knowledge worth having and he appears to reject the value of any other way of knowing. Doubtless science is the best approach towards all that can be investigated by science, but science is like a microscope, it enables one to see what one could not otherwise, but don't try to observe the heavens. Many things which are highly important to us human to use are out of the purview of science. I think of the tale of the man who is looking for his keys under the street lamp at night, and a man ask him what he is looking for, and he says his keys and he asked "where did you lose them?" and he points out to a dark area and says "Over yonder", so "Why are you looking here?", he answers, "because this is where there is light." For the author science is the light, but unlike this proverbial character, it would seem that instead of searching for those keys under the lamp, he has just decided the keys don't exist, or there is no point going out into the dark to look for something which science cannot illuminate.
I got the impression that the author doesn't see our beliefs as substantially different from the "beliefs" of a machine, computer, or robot. To me consciousness is a huge factor here that he is ignoring. I don't know, perhaps Nils is one of those who think consciousness is an illusion, that there is no free will, that we simply are molecular machines fooled into thinking we have a say in anything. Consciousness is one of those things science still cannot grapple with, so it wouldn't surprise me if despite it being the most obvious of all realities, he denied it. But if he doesn't deny it the reality of consciousness, it seems consciousness means beliefs for humans is qualitatively different than "beliefs" for computers and robots which are not conscious.
The other, in light of the Kantian idea (he doesn't however mention Kant) that though reality exist, we cannot directly know it as it is, but only our perception of it, he mentioned how our beliefs, are like the pilot's trust of the instruments of realities he isn't directly privy to. It is important that the meters and gauges to be well tested and accurate, less he fly into a mountain or enter a nose-dive, so we should be careful about the beliefs we adopt.
Nils seemed to be a naturalist and believes science to be the only avenue towards any knowledge worth having and he appears to reject the value of any other way of knowing. Doubtless science is the best approach towards all that can be investigated by science, but science is like a microscope, it enables one to see what one could not otherwise, but don't try to observe the heavens. Many things which are highly important to us human to use are out of the purview of science. I think of the tale of the man who is looking for his keys under the street lamp at night, and a man ask him what he is looking for, and he says his keys and he asked "where did you lose them?" and he points out to a dark area and says "Over yonder", so "Why are you looking here?", he answers, "because this is where there is light." For the author science is the light, but unlike this proverbial character, it would seem that instead of searching for those keys under the lamp, he has just decided the keys don't exist, or there is no point going out into the dark to look for something which science cannot illuminate.
I got the impression that the author doesn't see our beliefs as substantially different from the "beliefs" of a machine, computer, or robot. To me consciousness is a huge factor here that he is ignoring. I don't know, perhaps Nils is one of those who think consciousness is an illusion, that there is no free will, that we simply are molecular machines fooled into thinking we have a say in anything. Consciousness is one of those things science still cannot grapple with, so it wouldn't surprise me if despite it being the most obvious of all realities, he denied it. But if he doesn't deny it the reality of consciousness, it seems consciousness means beliefs for humans is qualitatively different than "beliefs" for computers and robots which are not conscious.
Read
August 14, 2025fine book if a little too introductory, I don't know if you should be using beatles lyrics as an academic source. Also incredibly STEM brained which does offer a unique perspective but it does mean the author ends up disparagingly comparing John Keats to Richard Dawkins which is upsetting for anyone to read.
September 24, 2023
UNDERSTANDING [ALL KNOWLEDGE AS] BELIEFS
1. This book is no treatise on religion or superstition, conspiracy thinking or self-help nonsense. Nilsson believes that all declarative knowledge is just belief--we can tell about reality but not how reality is. Our theories are limited by our perception and our perception is biased by other beliefs.
2. Nilsson is neither a constructivist nor a relativist though. He finds himself in the group of "scientific instrumentalists" who avoid the dispute over the reality or non-reality of thinking that is isolated from practice. Scientific Instrumentalism considers the truthfulness of ideas determined by their ability to enable accurate predictions. There is no real discussion on other paradigms or epistemology in this book, which is okay for me, since you can read about that in depth elsewhere. Thinking about "the faculties of knowledge" or denying truth is self-referentially inconsistent anyway.
3. Nilsson introduces us to his "meta-beliefs" on beliefs, touches (Bayesian) belief networks and advices us to assess the credibility of a belief by scientific standards, which take up a good part in his book. Then something like this: "You may disagree with them. But, after all, you can take them simply as my beliefs!"—with that he could have saved himself and others the whole book and the arguments, if one can simply believe one or the other. Yet, he argues in the book that there are beliefs without (scientific) value. In science, nobody wants to have just meant.
4. The AI pioneer and former head of the Association for the Advancement of Artificial Intelligence talks a little about machine learning or "robot beliefs" (since we learn about us by studying AI too) and warns of belief-traps based on lifestyle or logical fallacies and psychological factors, e.g., the confirmation bias.
This book, however, doesn't thoroughly discuss many cognitive biases or fallacies; there are exhaustive lists on Wikipedia.
5. Nielsson admits that psychologists and neuroscientists don't yet know very much about beliefs and how they are represented in human brains, so you won't read anything about the matter in Nilsson's book either.
"Understanding Beliefs" is a quick, informal read and well written, balanced in scope and nicely designed. Nevertheless, Nilsson's book is quite introductory. If you're already familiar with critical thinking (well everyone think he is) or with the scientific method this book is an enjoyable refresher. All books from the MIT Press' Essential Knowledge series are pocket books with a pleasant stiff and glossy softcover. The key statements are repeated every few pages in big white letters on a separate black book page.
1. This book is no treatise on religion or superstition, conspiracy thinking or self-help nonsense. Nilsson believes that all declarative knowledge is just belief--we can tell about reality but not how reality is. Our theories are limited by our perception and our perception is biased by other beliefs.
2. Nilsson is neither a constructivist nor a relativist though. He finds himself in the group of "scientific instrumentalists" who avoid the dispute over the reality or non-reality of thinking that is isolated from practice. Scientific Instrumentalism considers the truthfulness of ideas determined by their ability to enable accurate predictions. There is no real discussion on other paradigms or epistemology in this book, which is okay for me, since you can read about that in depth elsewhere. Thinking about "the faculties of knowledge" or denying truth is self-referentially inconsistent anyway.
3. Nilsson introduces us to his "meta-beliefs" on beliefs, touches (Bayesian) belief networks and advices us to assess the credibility of a belief by scientific standards, which take up a good part in his book. Then something like this: "You may disagree with them. But, after all, you can take them simply as my beliefs!"—with that he could have saved himself and others the whole book and the arguments, if one can simply believe one or the other. Yet, he argues in the book that there are beliefs without (scientific) value. In science, nobody wants to have just meant.
4. The AI pioneer and former head of the Association for the Advancement of Artificial Intelligence talks a little about machine learning or "robot beliefs" (since we learn about us by studying AI too) and warns of belief-traps based on lifestyle or logical fallacies and psychological factors, e.g., the confirmation bias.
This book, however, doesn't thoroughly discuss many cognitive biases or fallacies; there are exhaustive lists on Wikipedia.
5. Nielsson admits that psychologists and neuroscientists don't yet know very much about beliefs and how they are represented in human brains, so you won't read anything about the matter in Nilsson's book either.
"Understanding Beliefs" is a quick, informal read and well written, balanced in scope and nicely designed. Nevertheless, Nilsson's book is quite introductory. If you're already familiar with critical thinking (well everyone think he is) or with the scientific method this book is an enjoyable refresher. All books from the MIT Press' Essential Knowledge series are pocket books with a pleasant stiff and glossy softcover. The key statements are repeated every few pages in big white letters on a separate black book page.
May 19, 2023
Recommended for: people who haven't read much about rationality and epistemology, as it's a fine primer on current topics in those areas. Joe Rogan fans maybe.
Not recommended for: People well versed in Less Wrong/rationalist communities. I didn't see anything surprising or new.
The author gets 5 points for mentioning Feyerabend in the Scientific Method chapter, and 4 points deducted for neutering the thesis of 'Against Method'. One wonders how many other cited authors in this little book are given a similar treatment.
Not recommended for: People well versed in Less Wrong/rationalist communities. I didn't see anything surprising or new.
The author gets 5 points for mentioning Feyerabend in the Scientific Method chapter, and 4 points deducted for neutering the thesis of 'Against Method'. One wonders how many other cited authors in this little book are given a similar treatment.
September 29, 2020
2020.09.28–2020.09.28
Contents
Nilsson NJ (2014) (02:46) Understanding Beliefs
Series Foreword
Preface
• About the Notes
Acknowledgments
1. Beliefs, Knowledge, and Models
• One of the most important things to say about beliefs is that they are (or at least should be) tentative and changeable.
• Before we trust a belief sufficiently to act on it, we can analyze it and perhaps modify it—taking into account our own experiences, reasoning, and the opinions and criticisms of others.
2. What Do Beliefs Do for Us?
• Our beliefs play important roles in perceiving a current situation, in identifying appropriate actions, and in predicting the effects of these actions.
• We use beliefs to predict, to explain, to create, to inspire, to be entertained, to feel good, and to buttress confidence.
3. Where Do Beliefs Come From?
• All of our beliefs are mental constructions. Some are consequences of other beliefs, and some are explanations built to explain existing beliefs and experiences.
• We do know that explanations can only be constructed from the materials at hand—that is, from whatever beliefs and concepts that happen to be around.
4. Evaluating Beliefs
• Because missing out on useful beliefs or accepting bad ones can have life-altering consequences, we should back up our intuitions about beliefs with more disciplined, critical thinking.
• On many things, our minds are made up. But they can only stay made up if we never challenge them with new experiences, new information, and discussions with knowledgeable people who might hold opposite beliefs.
5. In All Probability
• The structure of a belief network encodes information about which beliefs directly affect other beliefs. To over-simplify, beliefs are influenced mainly by neighboring beliefs in the network.
• In their everyday reasoning activities, people frequently use informal versions of causality, evidential, and explaining-away methods. It is easy to be misled, however, by failing to appreciate some of the subtleties of probabilistic reasoning.
6. Reality and Truth
• Even some theologians around the time of Galileo agreed that there was a difference between reality itself and descriptions of reality.
• ‘Absolute truth’ is just a label we apply to certain beliefs that are held very, very strongly and permanently.
7. The Scientific Method
• People have a lot of beliefs that are not falsifiable, and therefore such beliefs cannot be considered to be scientific.
• Ideas that are immune from debate can never be in good standing in science, nor should they be in daily life.
8. Robot Beliefs
• A computer system’s beliefs can be updated by additions, modifications, or deletions of propositions in the system’s database.
• Considering how computer systems acquire, create, organize, and evaluate beliefs might provide a useful guide for how people do these things.
9. Belief Traps
• When people discuss beliefs only with like-minded people, their beliefs become more extreme.
• To be effective parents or citizens though, or for our personal well-being, what we believe about many things does matter.
Glossary
Notes
Further Readings
Index
Contents
Nilsson NJ (2014) (02:46) Understanding Beliefs
Series Foreword
Preface
• About the Notes
Acknowledgments
1. Beliefs, Knowledge, and Models
• One of the most important things to say about beliefs is that they are (or at least should be) tentative and changeable.
• Before we trust a belief sufficiently to act on it, we can analyze it and perhaps modify it—taking into account our own experiences, reasoning, and the opinions and criticisms of others.
2. What Do Beliefs Do for Us?
• Our beliefs play important roles in perceiving a current situation, in identifying appropriate actions, and in predicting the effects of these actions.
• We use beliefs to predict, to explain, to create, to inspire, to be entertained, to feel good, and to buttress confidence.
3. Where Do Beliefs Come From?
• All of our beliefs are mental constructions. Some are consequences of other beliefs, and some are explanations built to explain existing beliefs and experiences.
• We do know that explanations can only be constructed from the materials at hand—that is, from whatever beliefs and concepts that happen to be around.
4. Evaluating Beliefs
• Because missing out on useful beliefs or accepting bad ones can have life-altering consequences, we should back up our intuitions about beliefs with more disciplined, critical thinking.
• On many things, our minds are made up. But they can only stay made up if we never challenge them with new experiences, new information, and discussions with knowledgeable people who might hold opposite beliefs.
5. In All Probability
• The structure of a belief network encodes information about which beliefs directly affect other beliefs. To over-simplify, beliefs are influenced mainly by neighboring beliefs in the network.
• In their everyday reasoning activities, people frequently use informal versions of causality, evidential, and explaining-away methods. It is easy to be misled, however, by failing to appreciate some of the subtleties of probabilistic reasoning.
6. Reality and Truth
• Even some theologians around the time of Galileo agreed that there was a difference between reality itself and descriptions of reality.
• ‘Absolute truth’ is just a label we apply to certain beliefs that are held very, very strongly and permanently.
7. The Scientific Method
• People have a lot of beliefs that are not falsifiable, and therefore such beliefs cannot be considered to be scientific.
• Ideas that are immune from debate can never be in good standing in science, nor should they be in daily life.
8. Robot Beliefs
• A computer system’s beliefs can be updated by additions, modifications, or deletions of propositions in the system’s database.
• Considering how computer systems acquire, create, organize, and evaluate beliefs might provide a useful guide for how people do these things.
9. Belief Traps
• When people discuss beliefs only with like-minded people, their beliefs become more extreme.
• To be effective parents or citizens though, or for our personal well-being, what we believe about many things does matter.
Glossary
Notes
Further Readings
Index
January 8, 2022
We are continuously driven by our beliefs - whether explicitly and consciously driven by them or implicitly and subconsciously guided by them unbeknownst to us. However, in most cases, we have not really tried to subject our deeply-help beliefs to a systematic inquiry after hard-wiring them at some point in life, and thus, refuse to update our "strength" in them, or even think of replacing them altogether. The result is often our blind trust in a belief that is outdated, and has perhaps outlived its utility. For example, I used to have a belief - rather was in a "belief trap" - that asking for help is not such a great idea. No, it was not an ego or a hollow vanity thingy for me - but simply that I didn't want to come across short to anyone lest they begin to think less of me. Over time, I saw how some of the most effective people not only routinely asked for help without losing any dignity or respect from others (or even self-respect!), I also found that the people who most asked for help were also among the ones most willing to help others generously with!
Personally for me, the most important learning about beliefs has been that we almost never surpass our beliefs, especially when we are not willing to "challenge" them meaningfully - for example, if I believe I can't learn French, there is no way I am ever going to learn it. But if I can somehow come to understand why is it that I believe it that way, and then go down the starting point of it, I might just be able to build (or perhaps, deconstruct) a hierarchy of beliefs that might raise my chances of learning French sometime in future. In the organisational setting, it might be much harder considering these all end up being shared beliefs by a large population, thus making it harder to change. Rather than attacking those symptoms, it is always more helpful to understanding this hierarchy and then work from the starting point without really confronting the widely-held beliefs, which might be more of symptoms. After all, people don't like to be proven wrong by others - the best we can hope is when they decide to accept updated beliefs on their own!
https://mitpress.mit.edu/books/unders...
Personally for me, the most important learning about beliefs has been that we almost never surpass our beliefs, especially when we are not willing to "challenge" them meaningfully - for example, if I believe I can't learn French, there is no way I am ever going to learn it. But if I can somehow come to understand why is it that I believe it that way, and then go down the starting point of it, I might just be able to build (or perhaps, deconstruct) a hierarchy of beliefs that might raise my chances of learning French sometime in future. In the organisational setting, it might be much harder considering these all end up being shared beliefs by a large population, thus making it harder to change. Rather than attacking those symptoms, it is always more helpful to understanding this hierarchy and then work from the starting point without really confronting the widely-held beliefs, which might be more of symptoms. After all, people don't like to be proven wrong by others - the best we can hope is when they decide to accept updated beliefs on their own!
https://mitpress.mit.edu/books/unders...
September 6, 2021
Este libro te va a ayudar a entender varias corrientes de pensamiento sobre el conocimiento y el acceso a la realidad.
Una de las primeras cosas que establece es que no tenemos acceso directo a la realidad, sino que nuestros sentidos acceden a ella y nos dan un entendimiento limitado y algunas veces distorsionado.
La siguiente premisa que nos enseña, que a mi parecer es bastante razonable es que no podemos tener certezas absolutas sobre ningún tema ya que el conocimiento siempre puede cambiar, así que lo único que tenemos son creencias sostenidas con cierto grado de firmeza. Lo que llamamos certezas o "conocimiento" son creencias que es muy muy poco probable que cambién.
Luego, da varios puntos para evaluar las creencias y establecer su valía o su utilidad, algunos de esos puntos son:
- Su poder predictivo: qué tanto pueden predecir cosas que todavía no han pasado
- Su poder explicativo: qué tanto pueden explicar cosas que observamos. ¿Existe una mejor forma de explicar eso que estamos viendo?
- Su capacidad de ser explicados: ¿existen explicaciones creíbles para esto que estamos afirmando?
- ¿Es falseable? Esto es, que hay posibilidad de probarlo falso si suceden ciertas cosas. Las creencias no falseables tienen un alto probabilidad de ser falsas.
- Escuchar la opinión experta. Si tu creencia va en contra de la mayoría de los pensamientos de expertos es probable que esté equivocado.
También habla un poco sobre la forma de representación del conocimiento en sistemas automáticos.
El libro termina hablando sobre cómo evitar trampas del pensamiento y sesgos que nos pueden llevar a tener creencias poco útiles o creíbles. Una cosa que deja claro el libro es que el escrito mismo son las creencias del autor sobre las creencias, bastante razonados y evaluados, pero a final de cuentas sujetos a cambios después de encontrar nueva información.
Una de las primeras cosas que establece es que no tenemos acceso directo a la realidad, sino que nuestros sentidos acceden a ella y nos dan un entendimiento limitado y algunas veces distorsionado.
La siguiente premisa que nos enseña, que a mi parecer es bastante razonable es que no podemos tener certezas absolutas sobre ningún tema ya que el conocimiento siempre puede cambiar, así que lo único que tenemos son creencias sostenidas con cierto grado de firmeza. Lo que llamamos certezas o "conocimiento" son creencias que es muy muy poco probable que cambién.
Luego, da varios puntos para evaluar las creencias y establecer su valía o su utilidad, algunos de esos puntos son:
- Su poder predictivo: qué tanto pueden predecir cosas que todavía no han pasado
- Su poder explicativo: qué tanto pueden explicar cosas que observamos. ¿Existe una mejor forma de explicar eso que estamos viendo?
- Su capacidad de ser explicados: ¿existen explicaciones creíbles para esto que estamos afirmando?
- ¿Es falseable? Esto es, que hay posibilidad de probarlo falso si suceden ciertas cosas. Las creencias no falseables tienen un alto probabilidad de ser falsas.
- Escuchar la opinión experta. Si tu creencia va en contra de la mayoría de los pensamientos de expertos es probable que esté equivocado.
También habla un poco sobre la forma de representación del conocimiento en sistemas automáticos.
El libro termina hablando sobre cómo evitar trampas del pensamiento y sesgos que nos pueden llevar a tener creencias poco útiles o creíbles. Una cosa que deja claro el libro es que el escrito mismo son las creencias del autor sobre las creencias, bastante razonados y evaluados, pero a final de cuentas sujetos a cambios después de encontrar nueva información.
September 1, 2018
Nilsson writes with precision, clarity, and conciseness. Thus the time spent reading this book is well worth it.
It is accessible to the non-expert, but also a joy for professional scientists, especially the chapter on the scientific method. I took a philosophy of science course at Iowa State University almost 50 years ago, and loved the clear, precise explanation provided by Nilsson and the illuminating examples. Everyone should read this chapter.
Writing in 2014, Nilsson seems to presage our current cultural difficulties, where one of our major political parties (at least its elected leaders) does not believe in science, nor exhibit understanding of how science works. The book explains why conspiracy theories are so rampant, and the errors in reasoning we now witness in our national discourse.
Two relevant quotes:
"all scientific theories must be falsifiable"
"People have a lot of beliefs that are not falsifiable, and therefore such beliefs cannot be considered to be scientific."
It is accessible to the non-expert, but also a joy for professional scientists, especially the chapter on the scientific method. I took a philosophy of science course at Iowa State University almost 50 years ago, and loved the clear, precise explanation provided by Nilsson and the illuminating examples. Everyone should read this chapter.
Writing in 2014, Nilsson seems to presage our current cultural difficulties, where one of our major political parties (at least its elected leaders) does not believe in science, nor exhibit understanding of how science works. The book explains why conspiracy theories are so rampant, and the errors in reasoning we now witness in our national discourse.
Two relevant quotes:
"all scientific theories must be falsifiable"
"People have a lot of beliefs that are not falsifiable, and therefore such beliefs cannot be considered to be scientific."
August 6, 2020
Wonderful concluding chapter, so true today in 2020 as it was in 2014 as he wrote it; which for me raises the rest of the book of compelling evidence and argument to a time-poignant 5 star review.
Citing many seminal authors and books specialising in a variety of areas, from neuro-science, cognitive science, philosophers on areas of meta-beliefs, historical scientific theory development and current day global debates on climate change, conspiracy and to long standing ideological arguments in theism and evolution. Nilsson brings together these subject excerpts, which I have enjoyed reading in their origins and here, to form his “tightwire” arguments for degrees of belief based on Bayesian probability, 3 types of beliefs (standard, mathematical and scientific), the importance of critical discussion along with the constraints upon reassessing beliefs. The final chapter brings together these points in the frame of today’s big data giants, who (although slightly differently than in 2014) help deliver vast quantities of new information to vast quantities of people, via imperfect information delivery/imperfect critical discussion processes to our imperfect human cognition processes.
Citing many seminal authors and books specialising in a variety of areas, from neuro-science, cognitive science, philosophers on areas of meta-beliefs, historical scientific theory development and current day global debates on climate change, conspiracy and to long standing ideological arguments in theism and evolution. Nilsson brings together these subject excerpts, which I have enjoyed reading in their origins and here, to form his “tightwire” arguments for degrees of belief based on Bayesian probability, 3 types of beliefs (standard, mathematical and scientific), the importance of critical discussion along with the constraints upon reassessing beliefs. The final chapter brings together these points in the frame of today’s big data giants, who (although slightly differently than in 2014) help deliver vast quantities of new information to vast quantities of people, via imperfect information delivery/imperfect critical discussion processes to our imperfect human cognition processes.
October 21, 2019
People use the word "know" for their strong beliefs.
There is only one element of rationality in our attempts to know the world - It is the critical examination of our theories. These theories themselves are guesswork. We don't know we only guess.
Changing our minds is difficult but it is necessary if we want to have more useful descriptions of reality.
Past performances no guarantee of future results.
We can only say things about reality. We can never say what it is. And most importantly what we say about is always subject to revision.
Albert Einstein once said: the whole of science is nothing more than the refinement of everyday thinking.
The spirit is the same: Observe, Explain, and Test.
There is only one element of rationality in our attempts to know the world - It is the critical examination of our theories. These theories themselves are guesswork. We don't know we only guess.
Changing our minds is difficult but it is necessary if we want to have more useful descriptions of reality.
Past performances no guarantee of future results.
We can only say things about reality. We can never say what it is. And most importantly what we say about is always subject to revision.
Albert Einstein once said: the whole of science is nothing more than the refinement of everyday thinking.
The spirit is the same: Observe, Explain, and Test.
May 15, 2024
Decent. However, Nilsson omitted or overlooked a fundamental aspect of beliefs that I think ought to be mentioned, namely, that beliefs appear to be true to the beholder. In other words, to believe is to hold something to be true. Indeed, no one holds to be true what they know to be false. A consequence of this is that if one were to amass in one set the totality of ones beliefs, one would not be able to discern which ones were false…
An important point to retain is the following: what you believe is crucial because what you do is determined by what you hold to be true. Thus, critical evaluation becomes necessary.
An important point to retain is the following: what you believe is crucial because what you do is determined by what you hold to be true. Thus, critical evaluation becomes necessary.
February 10, 2023
A fair amount that I already knew, but a good primer on the distinctions between belief as it’s commonly understood, and the scientific version of believing something to be true. I liked the author’s analogy of comparing the beliefs we choose to clothes we wear, and how our personal preferences and desires will shape our belief system accordingly, unless we choose to evaluate our worldview in an rigorous scientific manner. Worth a read if you’re interested in reasoning, critical thinking, and how we come to form worldviews
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October 7, 2022Why do we believe what we believe? How do we know that the beliefs we hold are true – or that they’re held by others? This fundamental philosophical problem of our existence is the one that’s addressed in Understanding Beliefs. It’s a walk through the land of what beliefs are, how they’re connected to what we know, and how they can sometimes be distorted.
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April 16, 2018
A good little book. Useful for the layperson as well as undergraduates.
April 19, 2021
Easy-going essay that introduces you to the basics of beliefs and their associated metaphysics.
not-in-pima-okc-wi-but-want
February 19, 2022Same subject different book might be ok.
This has been wished for on paberbackswap.
This has been wished for on paberbackswap.
February 5, 2023
Excellent book, although I wish the book was a little bit longer. Nilsson did give fairly thorough explanations of how a belief system works.
January 15, 2025
Un libro sobre cómo creemos que creemos. Muy buena introducción a la epistemología y sobre todo, a uno de los temas mas pertinentes que aborda esa disciplina, a saber, las formas en que elaboramos nuestras creencias. Resulta muy pertinente en estos tiempos donde hay mucho sectarismo ideológico, teorías de conspiración y el sesgo de confirmación se ha amplificado con los algoritmos de las redes sociales.
January 16, 2025
a few too many times i felt the book was stating the obvious, but, maybe sometimes the obvious needs stating. good as an introduction, works for the series.
July 5, 2025
Pfuu this one was intense :) especially e joyed the chapter on the scientific method. I believe a metareview would do it justice.
June 16, 2025
This was rather entertaining and informative; our representations of reality, our modelling of the world is what keeps us alive and going and even provides some direction to our existence. The audible format is excellent; on the subject be sure to check out the works by Daniel Dennett and Steven Pinker.
May 31, 2025
A book about our beliefs: how they are formed, how we can evaluate them, and how we can be open to changing them. This series is meant to be short but I wish less topics were covered but the author covered them more deeply. Because of this I did not have a lot of new ideas I took away from this book despite finding the topic interesting and important. Despite this, I found it to be a good primer to the subject and would recommend it.
January 15, 2017
I enjoyed this book. It's not great but its language is simple enough that even the layperson would understand it, and I think that's very important that it's not over-complicated to the point where understanding where our beliefs comes from become off-limits only to the superior man.
Sometimes in our quest to all become superior man because none of us wants to become inferior man, I think we are really missing the point that we are all just common man and that there are actually no real 'definition' of extraordinary or ordinary man, except for the fact that it exists because everyone else just want to kick everyone's else butts.
I know I am digressing off the point here but what I want to say is that it's clear, concise, a simple and humbling attempt at defining beliefs as what it is without going over the top.
For those who are looking for extremely in-depth explanation on the knows-all of beliefs, this book might disappoint but for me, it was just the right amount of sweetness.
Sometimes in our quest to all become superior man because none of us wants to become inferior man, I think we are really missing the point that we are all just common man and that there are actually no real 'definition' of extraordinary or ordinary man, except for the fact that it exists because everyone else just want to kick everyone's else butts.
I know I am digressing off the point here but what I want to say is that it's clear, concise, a simple and humbling attempt at defining beliefs as what it is without going over the top.
For those who are looking for extremely in-depth explanation on the knows-all of beliefs, this book might disappoint but for me, it was just the right amount of sweetness.
March 10, 2017
Pretty good, as I've come to expect from the MIT Press Essential Knowledge series the information is detailed but succinct. A good introduction to understanding beliefs, Understanding Beliefs feels like a delightful precursor to explorations into more academic texts.
June 28, 2024
(19 September, 2014)
I initially bought this so I could try to understand the other side, i.e. those who believe in god(s), or crystal power, or past lives – or even the type of person who watched ‘Crossing Over with John Edward’. As such this was a monumental fail.
What it did do was encourage me to question my own beliefs, beliefs on their own merit and beliefs I admittedly do not even see as such.
It explains a few things in depth and touches upon other related topics, like an interesting conversation I had with a friend of mine about how we talk, specifically about how we inherently believe in anything we state or affirm. Scientific method, belief as a crutch, why we ignore facts (or what we view as), it’s all here.
A quick and easy read, and a good way to find out about ourselves and how we view our reality.
I initially bought this so I could try to understand the other side, i.e. those who believe in god(s), or crystal power, or past lives – or even the type of person who watched ‘Crossing Over with John Edward’. As such this was a monumental fail.
What it did do was encourage me to question my own beliefs, beliefs on their own merit and beliefs I admittedly do not even see as such.
It explains a few things in depth and touches upon other related topics, like an interesting conversation I had with a friend of mine about how we talk, specifically about how we inherently believe in anything we state or affirm. Scientific method, belief as a crutch, why we ignore facts (or what we view as), it’s all here.
A quick and easy read, and a good way to find out about ourselves and how we view our reality.
May 6, 2015
A gem of a book that I was able to read and understand even with a raging upper respiratory infection. Overall it was simple enough to be clear, while introducing a handful of complex philosophical concepts without overwhelming the reader. I had just one small complaint: there was a six page or so recitation of the history of the development of electromagnetic theory from Newton to quantum mechanics, which seemed to serve little purpose except to highlight that the author personally found it fascinating. Perhaps it was just because I already knew this history. Maybe those unfamiliar with this history would find that it fits just peachy.
July 15, 2015
Interesting little book. More from the perspective of what scientists learn about beliefs when they program robots to be more human like. It is a tough problem. Essentially the beliefs we have is a model of the world that we create inside our head. We then act according to this model and our actions are limited by the boundaries of these beliefs. Just like in programming a robot, many of these beliefs can be changed once we become aware of them and take action to adjust them. The field of robotics may ultimately teach us more about ourselves and it is going to be one fantastic journey!
February 21, 2015
A nice and easily-digestible overview of some basic philosophies of beliefs. I found the sections regarding the scientific method to be the most interesting aspect, though there were thought-provoking tidbits throughout most of the chapters.
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