Feedback

I'm reflecting on "closed-loop" and "open-loop" controls in science and engineering, and their relevance in everyday life.

In feedback loops, a controller (say, the experimenter, or a computer + physical control system designed by the experimenter) changes a control parameter to create a desired state of the system. A simple everyday example is central heating / cooling in a house. A thermometer measures the temperature of the house. The controller has a set point, say, 70 degrees F. If the thermometer measures the temperature go outside some range (say, 68-72 degrees), it will turn on the heat or AC to drive it back towards 70. The thermometer (measuring device) and heat/AC generators (drive) work together to create a state (70 degree house). The whole thing together, I call the "control system".

This is called "closed-loop" control because it has a thermometer that actively measures the state and tells the heat/AC what to do. However, there's also "open-loop" controls that aim to generate a state without continual measurement. These are automated systems that nonetheless create a certain state. For example, the watering bulbs that you can fill and stick into the soil near your plant are open-loop controls. The water leaks out at a slow rate, and should flow faster when the water is drier. But no one is telling it what to do! The mechanical design of the system is such that, if you put the bulb in the ground, it will keep your plant watered because that's its function.

Open- and closed-loop controls are both ubiquitous in science and engineering, and I study such controls in quantum systems. But lately I'm reflecting on how many things in my life are like these types of feedback control.

In my Zen practice, I see my zazen (sitting meditation) as a kind of open-loop feedback towards being a more kind, grounded, and aware person. Without my having to "control" myself actively -- e.g. thinking, "I should have been kinder! I should have been more aware!", simply by sitting everyday, I generate those qualities. When I am meditating consistently, my "kindness steady state" is definitely higher.

On the other hand, it is helpful to have direct feedback. This is what I get when I work with a teacher or talk to my spiritual friends. When I describe what I'm experiencing and challenges I am encountering in my practice, they can offer guidance that helps get me out of a "rut".

In practice, both types of feedback are essential. I think this is the case in all control systems, human and non-human. If we use open-loop blindly, without ever checking in to see if we are getting the results we are aiming for, we risk not seeing things that need to be addressed. For example, maybe the water bulb is actually leaking all the water all at once because there's a small hole. If we don't check at all and just assume it's working, we're going to overwater our plants. On the other hand, using a closed-loop feedback like AC/heating, we may miss out on the fact that it's a beautiful day outside and we can open the windows and turn off the AC for a while.

I like to reflect, where am I in relying too much on one type of feedback or the other? Are there areas where I can relax and trust the process (open-loop feedback)? Are there places where I am really getting stuck and need to adjust, maybe with the help of a friend (closed-loop feedback)?

In the quantum feedback I study, I've found that the closed-loop controls are much harder to implement and require a precise understanding of the system. In contrast, open-loop controls are much easier to implement and require a big-picture understanding. Are there places where we are overcomplicating things using closed-loop? Are we missing out on a more interesting result by using open-loop?

In all cases, it's helpful to keep the goal in mind. Pay attention! Understand -- what actions, words, and thoughts help me cultivate kindness, humility and joy? There is no one right method, and soon, I'll be dead. So I try something, see what happens, and adjust.