>I think you're overselling the computational complexity of things like immune cells. They're not exactly navigating the body on a self determined path to find pathogens. There is no 'thinking' involved beyond reacting to a stimulus.

I never said they were thinking. This is why people get so hung up on the brain as a necessity for complex action and "behavior." Come take a walk with me. I'm going to describe Chemotaxis for you.

Chemotaxis is an important part of the movement of bacterial cells. Its how they swim toward food and away from danger/noxious components. In the long pill shape form of E.coli, usually at one tip there will be some transmembrane proteins. These proteins are receptors. Small molecules bind to these receptors, with things like amino acids and sugars being food and nickel ions and acids being noxious. About 4 kinds of receptor will be surveying the surroundings. When the right molecule binds to the receptor, it triggers a signal transduction cascade. Upon binding to the receptor, the chain reaction leads to a protein binding to another that is connected to the flagella. The binding turns it like a rotor, moving the flagella and the bacteria will tumble in one direction or another.

No thinking involved. But see how it didn't really need computation or anything either? It was purely a mechanical process at the molecular level. Molecule binds, chain link chemical reactions, different protein binds to another to become a spinning motor. Our immune cells are very much doing something similar, only more of it. It has the option of more receptor types, more space for those receptors, and more internal space and material for very many chain link reactions. Natural selection iterated and created enough of the "wiring" needed for an immune cell to carry out its wet work or support duties.

When you examine pathways like this with more types of cells, and think about all that is going on in the body when you scale this up, it is easier to imagine that it is entirely possible for us to operate without any abstract computation going on. You might say "thats so simple and limited, and that would make us no more than automatons," but you would be wrong. Because of the scale. There are trillions of cells in our bodies with a large enough genome to create an absurd variety of protein complexes. The "computing" power of this is IMMENSE. And its chemical soup, so its all a gigantic, fuzzy impossibly huge finite state machine diagram. There isn't any determinism to worry about because it's too many molecules, the combinatorial explosion is too intense.

Sequences of direct action and reaction that change "behavior" based on the current conditions of cell and its surrounding environment.

THIS is why I say there are no models in the brain. Based on what? Theres no need.

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>Your brain absolutely creates models or algorithms (or whatever you would like to call them). When you learn to ride a bicycle, for example, your brain creates a model of what you need to do to produce the desired result of riding a bicycle without crashing

Prove it. Where in the brain are the models stored. How are they accessed and updated. What is the biochemistry that is creating them. This is a well disputed concept in the field. Don't need models of bikes and desired results, just more chemotaxis if you think about it for a while.

We can waste time trying to decipher encoding schemes which might not even exist, or we can map the actual activity going on.