Max Tegmark quotes
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.
Max Tegmark
(...) 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.
Max Tegmark
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.
Max Tegmark
(...) 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.
Max Tegmark
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.
Max Tegmark
Let's instead define life very broadly, simply as a process that can retain its complexity and replicate. What's replicated isn't matter (made of atoms) but information (made of bits) specifying how the atoms are arranged. When a bacterium makes a copy of its DNA, no new atoms are created, but a new set of atoms are arranged in the same pattern as the original, thereby copying the information. In other words, we can think of life as a self-replicating information-processing system whose information (software) determines both its behavior and the blueprints for its hardware.
Max Tegmark
Yet the complexity of all this pales in comparison to the patterns of information processing in your brain. Your roughly 100 billion neurons are constantly generating electrical signals ("firing”), which involves shuffling around billions of trillions of atoms, notably sodium, potassium, and calcium ions. The trajectories of these atoms form an extremely elaborate braid through spacetime, whose complex intertwining corresponds to storing and processing information in a way that somehow gives rise to our familiar sensation of self-awareness. There's broad consensus in the scientific community that we still don't understand how this works, so it's fair to say that we humans don't yet fully understand what we are. However, in broad brush, we might say this: You're a pattern in spacetime. A mathematical pattern. Specifically, you're a braid in spacetime-indeed, one of the most elaborate braids known.
Max Tegmark
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!
Max Tegmark
This implication of the Mathematical Universe Hypothesis is pretty radical, so please pause your reading for a moment to 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.
Max Tegmark
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.
Max Tegmark
Third, this allowed us to propose what we called the cosmological interpretation of quantum mechanics. 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.
Max Tegmark
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.
Max Tegmark
[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 ...
Max Tegmark
Aristarchos of Samos... was able to use trigonometry 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...
Max Tegmark
