unit = terminal object = () = in SET Category, set with one element = in logic, proving “true”

terminal object = from every point in a category, there is one and only one arrow to the terminal object

two terminal objects are always have a uniquely ismorphic = only one way to isomorph between the two

you can return a unit from anything, a -> ()

can use unit to define the element of a set, one :: () -> int, two :: () -> int

as many unit -> t functions exist as elements in the type t

instead of talking about elements in category theory, we can talk about the function from unit