Quantum physics can predict the behaviour of particles and energy to an extraordinary degree. Quantum Electrodynamics, for example, predicts a value for the electromagnetic fine structure constant which is so accurate that we have not been able to find a difference between the predicted value and the real value despite measuring to 14 decimal points (the measurements are difficult!)
The point of this is that the result of the most precise measurements we have ever made can be predicted using some math, without needing to do the actual measurement.
This is because the universe is mathematical in nature. There is nothing in the universe which we don’t have a formula for.
A co-worker retorted “what about the soul?” Treating that like the serious question she intended it to be, even thoughts and so-called “free will” can be predicted using math. Thoughts are determined by processes in the brain involving chemistry and electricity; both of which are well understood and predictable.
We have artificial neural networks which work similar to the brain. While they sometimes do things that we don’t immediately understand and which look like thought, we can examine the weights and synapses of the network and break every thought and decision right down to the 1s and 0s that they’re made of.
Just because we don’t understand how something works, doesn’t mean that it’s magic. The brain is not magic. Each tiny part of the brain works in very precise and predictable ways, and the thoughts and decisions that we call “free will” emerge from the billions of neural firings that happen every second (13 billion per second! There are 86,000,000,000 neurons in the brain, and they all fire on average about .15 times per second).
Everything that happens in the universe is predictable by math.
Even the universe itself, devoid of all matter and energy, is still a mathematical structure. Why are there exactly three space dimensions? An answer can be found in a theory called “Causal Dynamic Triangulation“, which describes how exactly three dimensions of space can arise from a set of mathematical rules involving triangles. The theory is more accepted than the alternative highly-regarded “loop quantum gravity” theory, because it produces exact measurements between points (impossible in LQG), and because it describes space both for Planck-scale measurements (the smallest possible), and for astronomical scales as well.
The fact that everything in the universe is predictable with math, even space itself, allows the possibility that you can create a single equation that predicts absolutely everything that can happen.
And if you run that calculation? You would be able to pick a precise date and time, and tell exactly what the state of the universe is on that time (or at least, you would know the most likely layout – quantum mechanics is very precise but also fuzzy).
This is regardless of so-called “free will”. Everything is predictable, including thoughts, if you have enough starting information.
It gets weird now: if everything, including thoughts, can be predicted using a single (probably very complex) formula or algorithm, then how do you know that you are real?
I mean, if everything you do is simply a result of an algorithm following its steps one by one, as physics shows us, then are you anything more than just a bunch of variables in that algorithm?
And if so, then is there a difference between the algorithm running for real in some super-computer somewhere, as people like Elon Musk suggest, or running in potential simply because every mathematical algorithm that can exist must have results whether the algorithm is run or not?
Personally, I’m in the latter camp for a number of reasons:
1. If the universe is running in a super-computer somewhere, is the super computer real or running inside a simulation of its own?
2. The eternal question “why is there something rather than nothing” is solved forever if there really is nothing and everything we see is simply a shared simulation running in potential but not in “reality”.
3. It also helps explain another related issue – is there exactly one universe? No, there are infinite universes, for each possible result of this universal algorithm, and every single one of them “exists” is a result, even if they are not “real”.
4. What is reality? When he heard the idea that nothing is “real” and that reality is subjective (immaterialism), Samuel Johnson famously kicked a rock hard and shouted “I refute it thus!”. However, that’s not a refutation – in a universe where you and I share a hallucination, everything in that hallucination is real to us, whether the objects are objectively real or not.
A very welcome bonus to the idea that the universe is mathematical in nature, is the possibility that it leads to personal immortality, through the idea of quantum immortality.