As scientific fields go, both physics and cosmology arguably get to have the most fun. I don’t mean in terms of day-to-day humdrum research, but in terms of speculation at the frontiers of knowledge.
Consider for example the pleasures of the multiverse. The harder astronomers work to pin down the fundamental parameterizations of the cosmos, from its matter contents to its ordinary energy and dark energy, the more it looks like a reality borne from the physics of inflation. This is a phenomenon that produces exponential expansion of space, resulting in the noise of quantum fluctuations on teeny tiny scales ending up as the seeds of structure on cosmic scales – like galaxies and stars. It also propels a universe towards a spatially flat geometry. And inflation, as we currently think of it, seems to almost inevitably lead to many, many, many universes.
That’s fun (in the loosest definition of that term) because with enough physical realities maybe there really are repeats of everything that we know – right down to you, your dog, what you had for breakfast, and the text of this article that you’re reading right now.
Then there are more philosophically motivated arguments that perhaps our universe is the result of experimentation or deliberate simulation. Maybe it was born in a super-powerful particle accelerator out of something like an inflating, energetic monopole, or in a hugely advanced quantum computer capable of modeling an entire cosmos of atoms and photons. In either case the line between real and unreal is irrevocably blurred. For example, to simulate a universe that exhibits the mind-boggling complexity that we experience – or think that we experience – requires the construction of a model that is pretty much as mind-bogglingly complex and physical as if it actually existed as a mind-bogglingly complex and physical reality.
There are even arguments for why it is actually quite likely for us to be ‘inside’ such a simulation (where ‘quite likely’ is philosopher-speak for ‘who knows, but it’s good for the lecture circuit’). Specifically, even if only a very few species (assuming an external physical reality like the one we experience) are sophisticated enough to construct a universe simulation, they might end up running huge numbers of such simulations. Perhaps to explore the lives of their ancestors, or perhaps to show off to the neighbors.
In all cases, the consequence of there being vast numbers of simulated realities would be that it is far more likely that you are simulated than real – it’s just a numbers game. Indeed, since we are not yet technologically sophisticated enough to build such models the odds may be even greater that we are in fact a simulated ancestor species.
But whether this is a simulation, or a bona-fide physical reality produced by someone’s laboratory tinkering, an important question is raised.
That is: why aren’t things a bit better?
I mean, come on. A universe with an accelerating cosmic expansion – as we seem to have - is astonishingly inconvenient. In a few hundred billion years it will become extremely difficult, if not impossible, for a sentient species to make any kind of meaningful sense out of the cosmos – as distant matter becomes effectively unseeable due to the expansion of spacetime. There are other issues too. Already the rate of star formation has dropped to a mediocre level, ensuring a future consisting mostly of dismal little red dwarfs and few new planets. And what about the peculiarities of physics – from quantum mechanics to thermodynamics and all of this ‘emergent phenomena' stuff? Honestly, it does seem a bit patched together.
Which brings me to a disquieting conclusion and new twist to the idea that we might exist within a manufactured universe. Even for some hyper-advanced intelligent species, building or simulating universes would have to be quite costly in terms of resources. Therefore, it’s not unreasonable to expect that some corners have to be cut, some expenses kept under control.
I’m reminded of the legend of the dry comment often attributed to the astronaut Alan Shepard when asked how he felt sitting atop an enormous rocket about to blast off to space. His response was (with some likely paraphrasing added over the years) “I just kept looking around at all those dozens of instruments in front of me and reminding myself that every one was supplied by the lowest bidder.”
Perhaps this is indeed the ultimate answer to why our universe is a little squirrely. While it is remarkable how well much of it can be understood – albeit with centuries of effort on our part – in other respects it is also highly resistant to being easily decoded. Built by the lowest bidder it would suffer from some corner-cutting, some inconsistencies and illogical quirks.
And that leads to the ultimate question, the one that we all seek the answer to.
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