# Lambda Calculus - Church Numerals

So while I was surfing on the internet, I bumped into things I picked when I was in school, lambda calculus being one of them. Now, I admit I’m not a theoretician or even a computer scientist, but this really amazed when I first learned it.

So it seems to me the great computer scientist, Alonzo Church, famously known for the Church–Turing thesis and lambda calculus (foundation of functional programming), had a problem he had to solve.

**He had to define (almost) everything computable in functions, so he could come up with lambda calculus**. And he couldn’t do it without first defining the natural numbers (0,1,…) with functions, so he went ahead and did that.

And the screenshot (2nd screenshot, obviously ;)) below was how he did it. By applying the function f, to the function x, n times, to replicate the idea of a natural number.