Summary

In this chapter, you learned what we need to know about category theory to be dangerous. We walked through history together, learning how functional programming came to be what it is today. We looked at logical propositions and proofs, sets, objects, and arrows as well as Lambda calculus. We shared in the amazement of the correspondence between category theory, logic, and Lambda calculus. And you saw how to apply what you learned in real-world scenarios (such as the flight of a soccer ball and doing business with untrusted partners). Lastly, we gained insight into how to design knowledge-based systems to derive value from big data.