Relationship
That's not the title, that's it. The TOE is just that - Relationship.
From The General Theory of Relativity (One object's Relationship with another) to being a good person (Your relationship with society). It all comes down to Relationships.
From the smallest particles, photons, and their relationships with other particles and how that in turn creates complex structures, to the largest truck and if it doesn't get out of your way, you're going to end up as a hood ornament, there are relationships going on all around us, all the time and it is these relationships that determine who and what we are.
There you go, simple. A <-> B
Alright, each relationship can be viewed in a more complex way, but fundementally, cut away all the math and other superfluous stuff and they all come down to a straight forward relationship between two things.
If you are a content person, then the phrase '
Happy with yourself' ends up being just another relationship.
So the TOE in fact it comes down to being
the relationship between one or more things.
PB.