Oh, man, did my philosophical heart flutter when I looked at the cover of the most recent New Scientist magazine and read:
WHAT THE UNIVERSE IS REALLY MADE OF: strip away human notions of reality and one thing remains
I feverishly turned to page 38. Finally, I'd know What It is All About. I had a suspicion. Which was confirmed when I saw the heading, "Reality by numbers."
Yes, it isn't wildly surprising that a science magazine would contain an article by a physicist, Max Tegmark, who believes that the essence of the universe is mathematical.
Surprising or not, the notion makes a lot of sense. For if you want to get beyond an anthropomorphic conception of reality, what's better to take you there than a pure abstract number? Tegmark talks about the search for a theory of everything, a complete description of reality:
My personal quest for this theory begins with an extreme argument about what it is allowed to look like. If we assume that reality exists independently of humans, then for a description to be complete, it must also be well-defined according to non-human entities – aliens or supercomputers, say – that lack any understanding of human concepts.
Put differently, such a description must be expressible in a form that is devoid of human baggage like "particle," "observation" or other English words.
In contrast, all physical theories that I have been taught have two components: mathematical equations, and words that explain how the equations are connected to what we observe and intuitively understand. When we derive the consequences of a theory we introduce concepts – protons, stars, molecules – because they are convenient.
However, it is we humans who create these concepts. In principle, everything could be calculated without this baggage: a sufficiently powerful supercomputer could calculate how the state of the universe evolves over time without interpreting it in human terms.
All of this raises the question: is it possible to find a description of external reality that involves no baggage? If so, such a description of objects in this reality and the relations between them would have to be completely abstract, forcing any words or symbols to be mere labels with no preconceived meanings whatsoever. Instead, the only properties of these entities would be those embodied by the relations between them.
Well, if you're only somewhat confused by this overview of Tegmark's outlook on reality, read his core paper "The Mathematical Universe" to dive into much deeper thought-waters.
I swam back to the surface of my usual mundane ideas after just a few pages. But while there I saw that Tegmark helpfully boils down his perspective to a couple of hypotheses: (1) There exists an external physical reality completely independent of us humans, and (2) Our external physical reality is a mathematical structure.
He admits that more than a few physicists (and lots of metaphysicians) disagree that reality exists without observation. Yet if the ERH (External Reality Hypothesis) is correct, it does make sense that the universe wouldn't be founded on human concepts.
After all, the cosmos preceded us by over thirteen billion years. Why would the root of existence be capable of being captured in a word like "God," "quantum," "vacuum energy," or "Buddha nature"?
So I like Tegmark's emphasis on shedding language-baggage. That's what most deep mystical philosophies do. He takes the same concept-less route in pursuing a scientific, rather than spiritual, approach to grasping the nature of reality.
Without words, what would religions rest on? Take them away and you're left with an appealing voidness, empty of dogmatism fueled by a belief that this description of the ultimate is how things really are.
Admittedly, there's more than a little feeling of vertigo – ooh, I'm spinning with no thought place to stand on! – if you embrace Tegmark's hypothesis. It takes some getting used to.
Ultimately, why should we believe the mathematical universe hypothesis? Perhaps the most compelling objection is that it feels counter-intuitive and disturbing. I personally dismiss this as a failure to appreciate Darwinian evolution.
Evolution endowed us with intuition only for those aspects of physics that had survival value for our distant ancestors, such as the parabolic trajectories of flying rocks. Darwin's theory thus makes the testable prediction that whenever we look beyond the human scale, our evolved intuition should break down.
I keep coming back to "don't know" as the wisest idea we could ever have about ultimate reality.