It's theoretical. We can see what happens in a thought experiment if what you say makes sense. See below.
That said: I have never said that slme organ or tissue is an equation (or any other thing going on in our mind). Mind stuff are dynamical effects, interactions. Not tje organs themselve. As in the relation between rjnning programs and the platform they run on.
I know that the artificial organ or tissue would actually have to be functioning in the tank. We would simulate the required functions immediately external to it so that it works just like the process in the brain.
If it works just like a brain, then it is a brain.
It will work like a
part of the brain. So now we are looking at what is minimally necessary for the equation 2 + 3 = 5 to exist out there. It is a dynamic structure but is also the equation. And it functions according to equations that model it.
What is interesting is that the equation seems static, but it is actually time dependant; it is "constructed" through time. The equation is 4 dimensional not 2 dimensional like it would seem to be.
Anyways, I would bet that if we simplified this equation to its absolute core function by simplifying the text, shapes, colours, irrelevant inner processes, memories associated with the equation, and even disregard every unnecessary cell and molecule, and then model a billion other different brains and compare the similarities which also would use different characters and imagine different characters for their number systems, the final product would be a relatively simple process that exists everywhere in nature. It would be universal information that means 2 + 3 = 5. Every advanced civilization would understand this language.