Logic
How people think has been on the mind of philosophers for ages. Aristotle had the most famous works on logic for around 2000 years. In the 1600’s Gottfried Leibniz attempted to improve on Aristotle’s logic by simplifying it and representing it in mathematical notation.
Two hundred years later George Boole further simplified Leibniz’s logic and notation into what we know today as Boolean algebra. Every introduction to computer science will teach you AND, OR, and NOT which are the foundational components of human logic.
In the 1930s Claude Shannon realized that he could apply Boolean logic in circuits using gates in what he called “switching algebra”. It didn’t matter if the circuits were made of wires with electrons or water with dams. Before Shannon no one connected the ideas that you could build circuits (e.g. electricity, telegraph networks) with any type of logic in them. Of course this thought later evolved into transistors and computer chips.
It’s amazing how much we take for granted in our education and career. We have the benefits of all the people who simplified complex ideas into teachable, concrete “facts” that are obvious in hindsight.