Is it? Is there any evidence that it's converting the signals to symbols and performing arithemtic on the symbols? Or is the signal processing being performed "directly", through the essentially analogue operation of the neurons?
Otherwise you're asserting "doing arithmetic" as a property of any analogue system, and would say that a falling ball needs to understand calculus in order to make an arc. Downthread someone is saying that crystal formation is "doing arithmetic". While there may be a philosophical sense in saying that all actions of the universe are in some sense arithmetical as they obey physical laws, this is not a useful way to talk.
What's the difference between "crystal formation" and cpu processing? They are both physical processes that don't understand the mathematical concepts that underpin their functioning. Maybe they do computation, but not math. Only humans can do math so far, and maybe some AIs, in a limited sense. Understanding math is harder than computing.
The point I'm trying to make is that computers "do arithmetic" through digital operations where there is a symbolic representation (through assigning analogue state to discrete symbolic values). Not through transistors operating continuously in their linear region.
Inside neuronal systems there doesn't seem to be a direct symbolic representation - and if there is, the neuronal patterns of somebody doing calculus on paper versus e.g. catching a ball are entirely different.
The symbolic representation is just a language though.
We might not be equipped to understand a language different from the formalisms we came up with.
Otherwise you're asserting "doing arithmetic" as a property of any analogue system, and would say that a falling ball needs to understand calculus in order to make an arc. Downthread someone is saying that crystal formation is "doing arithmetic". While there may be a philosophical sense in saying that all actions of the universe are in some sense arithmetical as they obey physical laws, this is not a useful way to talk.
(Repost of my comment above)