However, all of the finance theorists centrally discussed in this book would both strongly defend the virtues of their models and agree with Fama's assertion, quoted in chapter 4, that any model is "surely false" in the sense of not being an exact description of market realities. Finance theory is an epistemic culture that makes knowledge using models, but there is a deep ambivalence in the field's attitude to the extent to which its models can be taken as realistic.

Donald MacKenzie, An Engine, Not a Camera, loc. 1121