Our brain isn't a computer. That's the most recent metaphor we've used to try and make sense of the three pound organ in our heads.
Likewise, our brains are engines, converting energy from one form to another, and hence governed by thermodynamics. Again, that fact may or may not be useful for investigating properties of the brain we care about.
Our brains are also matter, meat, networks, made of atoms, and squishy. These are all facts, they may or may not be useful.
We use metaphors to help understand things we lack a literal explanation for, or the full explanation is complex and ongoing (neuroscience, biology, chemistry).
(And that's probably a very difficult question, considering you had to acquire the concept of symbolism, numbers and relationships)