Beta reduction is in fact the essence of LC - without it all you'd have is a nice tree. The beauty and generality of LC is that x doesn't need an explanation,

Beta reduction is in fact the essence of LC - without it all you'd have is a nice tree. The beauty and generality of LC is that x doesn't need an explanation, it is just a placeholder, yet that is enough to define interesting (perhaps all) things. Lisp is an abstraction, that per article can be built upon the deeper abstraction of LC - question is, what does it give us in terms of expressiveness and understanding?