Is there any possibility that a theory of everything would consist of one equation that could describe the whole universe, or will our laws of nature always be separate equations, each describing their own phenomenon?

Is there any possibility that a theory of everything would consist of one equation that could describe the whole universe, or will our laws of nature always be separate equations, each describing their own phenomenon?
For guymillion, I'd say quite possibly. I am a layman, admittingly, but I have noticed a common idea floating around when Theory of Everything is mentioned. And that is that several seemingly different phenomena can be explained and calculated from a single entity, e.g. a force.
Anyone correct me if I'm wrong, but I think String Theory says that all quantum occurences are a result of single, vibrating strings of energy, to put it in simplistic terms. The different vibration patterns appear as different states. So, for any theory in general, if that single source entity can be described with a single equation, then all the resulting phenomena can be perfectly explained with that one equation. The question in our reality is... Is all natural phenomena rooted in a single, universal occurence (possibly at the quantum level)?
This is where I sort of got the idea:
The Oneinch Equation to Explain All Physical Laws  Dr. Kaku's Universe  Big Think
It's an interesting thought.
There's no a priori reason to preclude the possibility (or at least I can't identify one). Now, it might be one really big equation, with lots of subparts...
More seriously, I think of physical laws (or the equations that express them) as a form of data compression; a few equations can describe succinctly an almost unimaginable range of phenomena. This idea of lawsascompression is a cousin of the same idea that underpins Occam's Razor. As with all compression methods, there is a limit to how far one can go. We don't know what that limit is for the physical laws that govern the universe, so we can't say how much compression is possible. We'll just keep going until we hit a limit, perhaps related to the (neg)entropy of the universe.
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