I think what the author means to say, and should have said in one paragraph, is that economics has not yet developed an appropriate language for their models. Economists are still trying to use calculus, which was thought of by physicists do describe physical phenomena, which, when used in economics, is leading to wildly inaccurate models.
I'm okay with econ being a social science (it sure wasn't taught in the Natural Science building at my school!), and I'm okay with being critical of the way its framework extends into my life. I don't understand how anyone can get through the gauntlet of econ warnings with hubris intact.
noun a branch of science which deals with the physical world, e.g. physics, chemistry, geology, biology
Eek, don't like it. What is "the physical world"? Or rather, what isn't part of "the physical world"? It's just a matter of creating models for phenomena of increasing complexity.
Just as biology studies a set of phenomena emergent from enormous amounts of bio-chemical interactions, which are emergent from quantum physics, etc., economics is emergent from the psychology, beliefs, and interactions of people.