Your definition of recursion is overly broad. var Y = function (F) { return (function (x) { return F(function (y) { return (x(x))(y);}); }

Your definition of recursion is overly broad. var Y = function (F) { return (function (x) { return F(function (y) { return (x(x))(y);}); }) (function (x) { return F(function (y) { return (x(x))(y);}); }) ; } ; [...] The Y combinator is a closed expression--it makes no explicit reference to an outside variable or to itself. Clearly, there is no recursion, iteration or mutation. Look at the definition of Y—there are no capital Ys after the 5th character (or any equivalent things like arguments.callee).