This paper attempts to assess how mathematical formalism is used in economics based on the dual perspective of epistemology and ethics. The demonstration principally concerns Popper’s critical rationalism, an epistemological posture widely adopted in economics. Economic science uses Popper’s proof of refutability, although only as a shield against the factors of internal limitation against which economic knowledge finds itself confronted. Acknowledging and giving meaning to these limitational factors would be a proof of scientific rigour and fruitfulness in economics, particularly in the science’s claims to an ethical dimension. Re-founding the ethical ambition of economics is something much called for today, with a view to restoring the much-battered relationship between man and nature.