Prof Max Tegmark
Max Tegmark is a physics professor at the Massachusetts Institute of Technology and the scientific director of the Foundational Questions Institute. Originally from Sweden, he studied in Stockholm before obtaining his PhD at Berkeley. His work focuses on theoretical work within cosmology and formulated the ‘ultimate ensemble theory of everything’ discussing the underlying mathematics of the universe. His first book, ‘Our Mathematical Universe’, was released in 2014.
We humans don’t know for sure how big our physical reality really is.
On becoming interested in science
When I was a kid I always loved mysteries, detective stories, but in high school, physics was actually my most boring subject and I couldn’t for the life of me understand what was supposed to be cool about this, and it was only later when I started reading this guy named Richard Feynman that suddenly a lightbulb went off in my head and I realised, actually, physics is a detective mystery and the best intellectual detective story of all time really, cause we’re trying to solve this grand mystery of what reality is all about, and best of all it’s one of these make it yourself books where you get to be part of the investigative team. I wrote this book not only because I wanted to convey a bunch of cool things we’ve figured out, but also because I wanted to convey how much fun it is to be part of this quest to try to figure out what our reality is all about, so if you who watches this decides to read my book it won’t just be my quest but our quest.
On being intimidated by maths
I think that one reason why people run away from the math and find that it’s a bit intimidating is because we think of math in a very limited way, either as a bag of tricks for manipulating numbers or maybe as a sadistic form of torture invented by schoolteachers to destroy our self confidence. Mathematicians these days have to think of math in a much more broad way, geometry and anything purely abstract that we can describe with our human language, and to me mathematics is something extremely beautiful, it’s fascinating, and to me this idea is actually not a scary idea, it’s a very encouraging and optimistic idea because it gives us just so much more power and ability to understand things. If you’re a detective, finding more clues is a good thing not a bad thing, and if I’m wrong about this and nature has some non-mathematical properties, that means that physics is ultimately going to be doomed, we’ll hit this roadblock, you know, after which there are no more of these clues to find and progress ends. Whereas if I’m right, there are no roadblocks, there’s absolutely nothing in our physical world that’s fundamentally off limits for us and our ability as humans to figure it out is ultimately only going to be limited by creativity and imagination.
On imagination in science
I don’t feel that a deeper understanding in terms of math in any way takes away from all the beauty and awesomeness of it, it won’t change in any way the feeling of love or the fragrance of a rose or the deliciousness of my favourite ice-cream flavour, it just gives a separate, additional perspective on it. Feynman, who’s the guy who’s book first got me excited about physics, I think put this very beautifully when some artist was griping to him that him studying things took away from the beauty, and he felt even though he wasn’t as talented an artist as his buddy that, you know, he could still appreciate the beauty of nature quite well, thank you very much, but that he saw additional beauty that this artist had missed. I feel that we humans, we’re no smarter now than our cave-dwelling ancestors but we have seen another layer of reality which is also very beautiful that they didn’t know about, you know, they looked at the stars and they said, wow, this is beautiful and awe inspiring, but they didn’t realise that the very oxygen circulating in their blood was actually made by stars, they didn’t realise that not only are we in our universe but that our universe is in us. So I feel that the better eyes that science gives us adds more beauty rather than less.
On physical reality
We humans don’t know for sure how big our physical reality really is but we’ve again and again made this mistake of thinking that it was actually smaller than it turned out to be, so we have to open for the possibility that it might be still bigger than the part that we can see today, which is what we call our universe, just the spherical region of space, you know, from which light has a time to get here so far during the 13.8 billion years since the Big Bang, and there are a lot of scientific predictions and ideas out there for how big it can be: the biggest of all is what I call the level 4 multiverse. It’s something so big and diverse that the universe described by every possible mathematical consistent set of equations, and if that’s the case then, um…
OK, so if there’s more stuff like this that exists in our universe, how much is there? We don’t know yet, but if space itself is much bigger than the part of space that we can see – which is what inflation theory, our most popular theory of the Big Bang predicts – then there are other regions our universe size that are also full of galaxies and stars, which I like to call level 1 parallel universes, and if someone is out there, they’d learn the same stuff as us in physics class but different things in history class because the particles will have started out in different places, causing things to just play out differently.
There can also be regions even farther away in space where a lot of the so-called physical constants that we thought were constant are actually not, but take different values. So if there are people over there too, they would learn different things not just in history class but also in physics class. And then there’s the third kind of parallel universe, which is predicted by the simplest version in quantum mechanics, in my opinion, the level 3 multiverse, which is kind of right here. It suggests that reality forks out into different parallel story lines, kind of like in the movie Sliding Doors, so if you find you just got a parking ticket, you can be happy to know that there’s a parallel version of you somewhere out there who didn’t, but maybe another version for whom the car actually got towed or stolen so, you know, you win some, you lose some.
That’s the three multiverses there, and the most diverse, most controversial multiverse of all is what I call level 4 multiverse in the book. It’s a multiverse that even the fundamental laws of physics – you know, my MIT students hope to put on a t-shirt one day – would be different. And ultimately it’s a question for science to figure out how big reality is. But since we’ve found again and again throughout history that we were wrong and underestimated the size of things, I think we need to examine this world with open minds.
On his controversial ideas
The reaction I’ve gotten to the really controversial parts in my book from my fellow scientists has been pretty good, all in all. They generally understand the logical arguments I’m making and they might beg to differ than me, you know, they think this particular thing is different, but they understand that…some people simply aren’t very interested in thinking about these big questions and I totally respect that; it’s actually very lucky that different physicists have different interests otherwise we would all be barking up the same tree.
The main critiques I tend to get are actually from people who are not particularly active scientists, who just…oh, this just sounds totally nutty, you know, the scientists have gone off the deep end. Basically, the point here again to remember is just that parallel universes are not a theory, they’re a prediction of certain physics theories, so if they want to criticise what the predictions are, they have to explain to us physicists what’s wrong with the physics theories, what’s wrong with the inflation theory, and, you know, what’s wrong with the Schrodinger equation, etc. They absolutely might be wrong, in physics we can never prove that any theory is correct. We thought Newton’s theory of gravity was correct cause it looked pretty good for hundreds of years and then Einstein realized, actually, not quite right. But at the same time, the flip side of this is if there’s a theory like inflation, which people keep sniping at and try to rule out and fail year after year and it’s still a popular theory, we’re kind of forced to take it more seriously even if we don’t particularly like the implications.
On an infinite universe
When you look at what the theory of inflation together with general relativity manages to accomplish, it seems to me a lot like watching a magician in a magic show, you’re so convinced that this cannot possibly be consistent with the laws of physics. Inflation says you can start with a finite volume and inside of that finite volume you can actually make an infinite space in there that doesn’t even sneak outside. Now it sounds even more crazy than something that David Blaine or David Copperfield would do. Yet when you study the math in detail, just like David Blaine, it turns out there’s all these clever tricks to just actually get around what you thought were the obstacles and accomplishes crazy, crazy things, for example, we think of space as something you can only get more of by taking it away from someone else, you know, in the Middle East. But actually, as Einstein realized, it can be stretched out, you can produce more volume without taking it away from anywhere else; space is more like an elastic membrane of sorts and what inflation does is it takes a puny subatomic space and it just keeps doubling and doubling and doubling. And within that tiny region, ultimately, because when you double something many times it gets very big, very fast, you have this mass of stuff larger than the universe flying apart at great speeds with all the right initial conditions ultimately give us this galaxy spangled universe that we live in today.