The Clean Code Blog

by Robert C. Martin (Uncle Bob)

The Brain Problem

28 July 2017

Imagine an information processing system composed of over 100 billion components that are deeply interconnected to one another. The interconnections are physical and dedicated – they aren’t on a buss. Imagine that the entire system is an analog computer. Analog computers are much faster, if less accurate, than digital computers. Imagine that the immense memory capacity of this device is also analog. The whole system is composed of myriads of feedback loops, filters, routers, sorters, and many more functions that we cannot even begin to imagine.

Imagine that each one of those 100 billion components are, themselves, highly complex and powerful analog information processors capable of transforming and communicating immense amounts of data in very short times. Imagine that at the core of each of these massive analog components there is an array of tens of thousands of digital processors executing a digital program that is tuned and customized just for it.

That’s what a human brain is. A human brain contains one hundred billion neurons. Each neuron is physically connected to thousands upon thousands of other neurons. Neuronal signals are analog in nature. Information is contained in the rate at which neurons fire. It is the pulse rate, not the pulses themselves, that contain and transmit information.

Each Neuron is, itself, a fantastically complicated information processor. Chemical signals, analog in nature, are communicated through an intricate labyrinth of fibers, tubules, channels, and membranes that are continuously forming and changing, and that specifically interconnect the components within the cell in the most dynamic fashion. The signals are contained in the quantity and nature of the tens of thousands of proteins that the cell can create, along with ions and other molecule concentrations. Virtually every molecule in a cell is a component in this processor. And each molecule can operate at the speed of molecular interactions. (i.e. fast). The raw information processing power of a single cell is vastly superior to a modern laptop.

What’s more cells signal each other using chemicals. Some simply send chemical signals to their neighbors. Others dump chemicals into the bloodstream to communicate with cells on the other side of the body. The number and form of chemical interconnections between and within cells is daunting.

If you want to get a flavor for how impressive this cellular machinery is, just watch this video. No. Don’t just watch it. Study it!

At the heart of each neuron there is a vast array of tens of thousands of digital processors, working to copy, repair, transmit, and execute the digital instructions contained within the DNA. These processors are, themselves, influenced by the analog chemical signaling within the cell.

So here’s the bottom line. Your brain is a highly efficient analog computer composed of a deeply interconnected array of one hundred billion analog processors of immense computational power, each driven by tens of thousands of digital processors that are monitored and controlled through interactions both from within and without.

Or, to say this another way, virtually every molecule, if not every atom, in your brain is an active component in the information processing going on between your ears.

The idea that our meager internet, which indirectly interconnects only a trifling few hundreds of millions of pitifully weak serial processors, could process the information of a single brain is absurd.

No, we will not be achieving artificial sentience any time soon.