I just learned Gottfried Wilhelm Leibniz (1646-1716), famous for inventing calculus, was also interested in the philosophy of mind. He proposed a concept called the Alphabet of human thought, which is an idea that says there is a universal way to represent all human thought with small primitive components. With these primitive components, we should be able to compose them in infinite ways to create new thoughts, compositionality! Chomsky’s work on computational linguistics seems to be a direct reference to these ideas. This idea from hundreds of years ago is a fundamental topic in Artificial Intelligence research. Now deep learning is the main focus of AI research and compositionality in neural networks still doesn’t work. Its fitting to see that one of the inventors of calculus was thinking about this problem hundreds of years ago and that the main AI research tool today are neural networks which are completely powered by calculus. So Leibniz was a mathematician, philosopher, engineer, and cognitive scientist, my kind of hero!