# Our Mathematical Universe - Author: [Max Tegmark](https://www.leafyquotes.com/max-tegmark.md) - Quotes: 25 - Book page: https://www.leafyquotes.com/max-tegmark/our-mathematical-universe ## Quotes > The very fabric of our physical world, space itself, could be a purely mathematical object in the sense that its only intrinsic properties are mathematical... as dimensionality, and topology. > In 1814... Joseph von Fraunhofer invented... a spectrograph, which let him separate white light into into a rainbow of colors... He discovered mysterious dark lines in the rainbow... and... the detailed positions of these lines... depended on what the light source was made of, constituting a kind of spectral fingerprint. During the following decades such spectra were measured and catalogued for many... substances. ...Sensationally, the spectrum of sunlight revealed that the Sun... contained elements... such as . Moreover... it revealed that stars are made of roughly the same mixture of gases as the Sun! This clinched it in favor of Bruno: stars are distant suns... > But I’ve suddenly changed my mind and turned more optimistic about our cosmic significance. Why? Because I’ve come to believe that advanced evolved life is very rare, yet has huge future potential, making our place in space and time remarkably significant. > So this book... [is] my personal quest for the ultimate nature of reality. > ... achieved a breakthrough. Please hold your thumb at arm's length and alternate closing your left and right eyes a few times. ...[Y]our thumb appears to jump left and right by a certain angle relative to the background... [M]ove your thumb closer... and you'll see this jump angle growing. Astronomers call this jump angle ... [W]e can... compare telescopic photographs taken six months apart, when Earth is on opposite sides of the Sun. ...Bessel noticed ... ...moved a tiny angle, revealing its distance to be almost a million times that to the Sun... Now that Bessel knew the distance he used... [the] to figure out how luminous it was... in the same ballpark as the Sun... Giordano Bruno had been right after all! > (…) the bottom line is that if you believe in an external reality independent of humans, then you must also believe that our physical reality is a mathematical structure. Nothing else has a baggage-free description. In other words, we all live in a gigantic mathematical object—one that’s more elaborate than a dodecahedron, and probably also more complex than objects with intimidating names such as Calabi-Yau manifolds, tensor bundles and Hilbert spaces, which appear in today’s most advanced physics theories. Everything in our world is purely mathematical—including you. > (…) no spectator is needed, because your consciousness basically is your reality model. I think that consciousness is the way information feels when being processed in certain complex ways. Since the different parts of your brain interact with each other, different parts of your reality model can interact with each other, so the model of you can interact with your model of the outside world, giving rise to the subjective sensation of the former perceiving the latter. > We're all born with curiosity, but at some point, school usually manages to knock that out of us. ...[M]y main responsibility as a teacher isn't to convey facts, but to rekindle that lost enthusiasm for asking questions. > What is real? Is there more to reality than meets the eye? Yes! was Plato’s answer over two millennia ago. In his famous cave analogy, he likened us to people who’d lived their entire lives shackled in a cave, facing a blank wall, watching the shadows cast by things passing behind them, and eventually coming to mistakenly believe that these shadows were the full reality. Plato argued that what we humans call our everyday reality is similarly just a limited and distorted representation of the true reality, and that we must free ourselves from our mental shackles to begin comprehending it. > [W]hat I had been missing... and what Feynman realized: physics is the ultimate intellectual adventure, the quest to understand the deepest mysteries of our Universe. ...[I]t makes us see more clearly, adding to the beauty and wonder of the world ...[T]he lens of physics adds more beauty to the world ... > Aristarchos of Samos... was able to use to figure out... the distance between the Earth and the Sun. His conclusion... the Sun was about twenty times farther... than the Moon and therefore twenty times bigger than the Moon. In other words, the Sun was... over five times bigger than the Earth in diameter. This insight prompted Aristarchos to propose the heliocentric hypothesis long before Nicolaus Copernicus... It turned out to be quite difficult to tell precisely when the Moon was 50% illuminated, and the correct Sun-Moon angle... isn't 87 degrees but about 89.85 degrees... This makes... the Sun... almost twenty times further away... and about 109 times larger than the Earth... [T]his wasn't corrected until almost two thousand years later, so when Copernicus came along... the overall scale of his Solar System model was about twenty times too small... > If there’s a singularity, would the resulting AI, or AIs, feel conscious and self-aware? Would they have an internal reality? If not, they’re for all practical purposes zombies. Of all traits that our human form of life has, I feel that consciousness is by far the most remarkable. As far as I’m concerned, it’s how our Universe gets meaning, so if our Universe gets taken over by life that lacks this trait, then it’s meaningless and just a huge waste of space. > Evolution endowed us with intuition only for those aspects of physics that had survival value for our distant ancestors, such as the parabolic orbits of flying rocks (explaining our penchant for baseball). A cavewoman thinking too hard about what matter is ultimately made of might fail to notice the tiger sneaking up behind and get cleaned right out of the gene pool. Darwin’s theory thus makes the testable prediction that whenever we use technology to glimpse reality beyond the human scale, our evolved intuition should break down. We’ve repeatedly tested this prediction, and the results overwhelmingly support Darwin. At high speeds, Einstein realized that time slows down, and curmudgeons on the Swedish Nobel committee found this so weird that they refused to give him the Nobel Prize for his relativity theory. At low temperatures, can flow upward. At high temperatures, colliding particles change identity; to me, an electron colliding with a and turning into a Z-boson feels about as intuitive as two colliding cars turning into a cruise ship. On microscopic scales, particles schizophrenically appear in two places at once, leading to the quantum conundrums... On astronomically large scales... weirdness strikes again: if you intuitively understand all aspects of black holes... put down this book and publish your findings before someone scoops you on the Nobel Prize for quantum gravity… [also,] the leading theory for what happened [in the early universe] suggests that space isn’t merely really really big, but actually infinite, containing infinitely many exact copies of you, and even more near-copies living out every possible variant of your life in two different types of parallel universes. > My guess is that we’ll one day understand consciousness as yet another phase of matter. I’d expect there to be many types of consciousness just as there are many types of liquids, but in both cases, they share certain characteristic traits that we can aim to understand. > (…) the . Here we interpret the wavefunction for an object as describing not some funky imaginary ensemble of possibilities for what the object might be doing, but rather the actual spatial collection of identical copies of the object that exist in our infinite space. Moreover, quantum uncertainty that you experience simply reflects your inability to self-locate in the Level I multiverse, i.e., to know which of your infinitely many copies throughout space is the one having your subjective perceptions. > I... ended up at the , focusing on environmental issues. I wanted to... make our planet a better place, and felt that the main problem... [was] that we didn't properly use... technology... I... was intrigued by... creating economic incentives that aligned... egoism with the common good. ...I soon grew disillusioned, concluding that economics was... intellectual prostitution... rewarded for saying what the powers that be wanted to hear. ...[T]he book that changed everything: ...[W]hat did Feynman see that I missed in high school? ...I sat down with... ... and started reading, "If... all scientific knowledge were to be destroyed... " ...I read on ...I felt like I was having a religious experience I finally got it! > Some ancients speculated that the stars were small holes in a black sphere through which distant light shone through. ...Giordano Bruno suggested that they were... like our Sun, just much farther away, perhaps with their own planets and civilizations... the Catholic Church had him burned at the stake in 1600. > [W]e've repeatedly underestimated not only the size of our cosmos, but also the power of our human mind to understand it. > (…) time is not an illusion, but the flow of time is. So is change. In spacetime, the future exists and the past doesn’t disappear. > It’s absolutely crucial that we don’t conflate this internal reality with the external reality that it’s tracking, because the two are very different. My brain’s internal reality is like the dashboard of my car: a convenient summary of the most useful information.' Just as my car’s dashboard tells me my speed, fuel level, motor temperature, and other things useful for a driver to be aware of, my brain’s dashboard/reality model tells me my speed and position, my hunger level, the air temperature, highlights of my surroundings and other things useful for the operator of a human body to be aware of. > A famous thorny issue in philosophy is the so-called infinite regress problem. For example, if we say that the properties of a diamond can be explained by the properties and arrangements of its carbon atoms, that the properties of a carbon atom can be explained by the properties and arrangements of its protons, neutrons and electrons, that the properties of a proton can be explained by the properties and arrangements of its quarks, and so on, then it seems that we’re doomed to go on forever trying to explain the properties of the constituent parts. The Mathematical Universe Hypothesis offers a radical solution to this problem: at the bottom level, reality is a mathematical structure, so its parts have no intrinsic properties at all! > There's no better guarantee of failure than convincing yourself that success is impossible... > This implication of the Mathematical Universe Hypothesis is pretty radical, so please pause (…) take it in and think about it. What you’re aware of right at this moment feels not like a photo but like a movie clip. This movie isn’t reality—it exists only in your head, as part of your brain’s reality model. It contains lots of information about the actual external physical reality—as long as you aren’t dreaming or hallucinating—but still constitutes only a very heavily edited version of reality, akin to the evening news on TV, mainly featuring certain highlights of patterns nearby in space and time that your brain thinks are useful for you to be aware of. > We humans replace the bulk of both our "hardware" (e.g., our cells) and our "software" (e.g., our memories) many times in our life span. Nonetheless, we perceive ourselves as stable and permanent. Likewise, we perceive objects other than ourselves as permanent. Or rather, what we perceive as objects are those aspects of the world that display a certain permanence. For instance, when observing the ocean, we perceive the moving waves as objects because they display a certain permanence, even though the water itself is only bobbing up and down. Similarly (…) we perceive only those aspects of the world that are fairly stable against quantum decoherence. > Eratosthenes... knew that the Sun was straight overhead in... Syene at noon on the summer solstice, but that it was 7.2 degrees south of straight overhead in , located 794 kilometers farther north. He concluded... 794 kilometers corresponded to 7.2 degrees out of the 360 degrees... around Earth's circumference, so that the circumference must be... 39,700 km...