The brain is the organism’s master system controller
Part 8 of Is “Is the brain a computer?” even a good question?
It’s too late to change the answer, and it distracts from the really useful questions about the relations between computers and brains. Nevertheless, a deeper look finds that brains stretch the definition of computing, perhaps beyond the breaking point.
This is the eighth and last part of a series of brief essays (sometimes very brief) on aspects of this question. Part 1 contains the introduction and an index to the whole series.
We’ve seen in earlier sections that the brain sometimes is part of a person called a “computer”, and because it does the computational aspects of those people, it gets called a computer itself. We’ve also seen that the the brain accomplishes those computational activities via very different mechanisms from those used by artificial computers. If you define a computer by how it works, the brain isn’t a computer. But we’ve also seen that modern devices called “computers”, such as your notebook PC or even your smartphone, don’t work in the way claimed by pundits who assert their authority to explain what’s a computer and what isn’t. Then your PC isn’t a computer either. Nor is your smart TV or your car.
So the brain both is and isn’t a computer. Maybe we should stop wasting time on this unresolvable debate. Unfortunately, issues like this aren’t resolved by everyone agreeing to stop talking and writing about it, and simply ending the discussion. The computer metaphor has one very useful property: it provides an everyday concept that can be used as a conceptual anchor to introduce the similar-but-different properties of brains to people who are interested in gaining more accurate insights into what’s really going on with that gray stuff in the head. If we can’t use the computer as that anchor, we need some other equally simple and powerful concept to use in its place.
The brain is the organism’s master system controller
If you have a need to be able to complete the sentence “The brain is a…” with some technical precision, I’d recommend saying something like “The brain is the master controller for the organism” and “The human brain is a universal system controller.” Those will be controversial in their own ways, but those ways will be substantive controversies rather than the merely terminological ones associated with the word “computer”.
The concept of a system controller is easy to explain. There are lots of simple examples of system controller that everyone is familiar with. Thermostats, steam engine speed governors, basement sump pumps, and auto cruise controls are used every day by nearly everyone, and can be related to biological concepts like homeostasis that are used to explain the stability of blood pressure or body temperature. It’s not hard to find examples of control systems that control other control systems, such as aircraft autopilots that control servo-activated elevators and ailerons. Control systems can be explicit like the ones that will guide self-driving autos in tunnels, or implicit like the operation of the cone-shaped wheels that keep railroad trains on their tracks. Control systems are involved in medical conditions like spinal and cerebellar tremor, Parkinson’s disease & ocular nystagmus.
The idea of a control system ends up with a much better fit to the current state of “computational neuroscience” than the idea of a computer. That doesn’t mean that computers aren’t critical for studying the brain and its operations, even at theoretical levels. The ability to easily create new simulations that comes with universal artificial computers makes computers the essential tool for studying complex systems, where experiments can find necessary conditions for the existence of a neurobehavioral phenomenon, but only simulation can show that our understanding has achieved enough power to be sufficient to reproduce that phenomenon. And even for the very complex phenomena that are studied by cognitive neuroscientists, where the brain is functioning as a natural computer, adoption of a control perspective provides an important element of ecological validity, keeping our view of the brain situated in its proper environment rather than isolated in an artificial lab setup. Understanding how neural control systems achieve the ability to emulate other control systems will provide a formal theoretical link between the capabilities of brains and those of artificial computers.
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