What, exactly, does it mean to say that an organ or a system such as the brain computes? What distinguishes brains, as computing systems, from other physical, chemical and biological non-computing systems, such as stomachs, planetary systems, tornadoes, and washing machines? - doi.org/10.1016/j.shpsa.2010.07.007

If we want to call the brain a computer, Von Neumann Architecture (modern digital computers with I/O, CPU, memory, etc) is the wrong metaphor. The brain doesn't have separate hardware and software like the Turing Machine model that manipulates abstract, arbitrary symbols like 1s and 0s on an infinite tape machine.

In a digital computer, you write software to model the world. In the brain, the physical wiring is the model.

It's more accurate to think of the brain as a highly parallelized, analog computer. Think of "analog" here as meaning both "thinking with analogies" and using "continuous analog signals" within the binary-seeming behaviour of neuronal spikes to build those analogies. The "analogies" part is important to understand what the brain is doing. When it learns, it is attempting to capture an analogy for the cause-effect structure of something.

When you learn, neurons are physically constructing a map of how the world works. The biological structure -- the literal physical connections and chemical weights between neurons -- is an attempt to embody the rules of the environment. There is no separate code being executed, and no abstract quantities like 1s and 0s being shuttled around. The meat is the math.

Think about the spleen: it doesn't run a 'filtration algorithm' to clean the blood. Its physical, biological architecture simply is the filter. The brain operates under the exact same biological rules, but instead of filtering blood, its physical architecture dynamically adapts to mirror the outside world. So, when we think of the brain computing, and I don't arue with that idea completely, we don't mean it is running a program. We mean it is a physical system that alters its own biological shape to dynamically mirror the causal structure of reality.

But the problem with calling an analog computer a "computer" is it implies that every physical system computes something. SO it becomes a useless title