Why “Our Brains Are Unique” is Wrong

A Dynamical Systems Perspective

Many suggest that humanity is about our brains (and our nervous systems and bodies too). This is wrong. Here’s why, from a dynamical systems perspective. Let’s start with a quick primer on dynamical systems.

A dynamical system is a system that updates its state over time, based on inputs and its previous state. Outputs are a function of state (and inputs, though that’s redundant). It can be expressed as differential equations, an agent-based model, a recurrent neural network, a computer program, or otherwise. The system can operate according to time slices or continuous time, and the signals can be digital or continuous-valued. That is, digital or analog in time or value. The inputs, state, and outputs may each be stochastic. That is, they can include randomness.

Here’s an awesome idea from the dynamical systems view of the world: once you have a model of a system, then you can instantiate those dynamics in whatever substrate you please! In a second-year engineering course on linear systems, we would draw an electrical circuit, then convert it to differential equations, then to thermal systems, then mechanical systems, and so on. There are equivalents for resistors, capacitors, inductors and the like in a wide variety of substrates. Nonlinear dynamics are no different.

Naturally, some substrates perform better than others for certain tasks; this is why we use electric circuits to manifest logical state machines rather than rat logic. (Yes, you can construct logic circuits based on rats in cages!)

Thanks to Moore’s Law, silicon has advanced incredibly far as a way to instantiate computational state machines.

Our brains (and bodies) house patterns of intelligence. They are simply dynamical systems.

So when people suggest that humanity is about our brains / nervous systems / bodies too, my response is: no. That’s just one instantiation. It’s a pretty sub-optimal substrate in many ways: frequency is orders of magnitude smaller than silicon; we forget even when we don’t want to; we can’t parallelize beyond our skulls; and more.