 This problem is made more pressing in conjunction with the Marburg attack on the given. (After all, if there were something given in experience, then the given in experience would determine which conceptual changes are necessary in science, and the objectivity of our scientific knowledge could be explained.) In the philosophy of science, the attack on the given amounts to an attack on the possibility of crucial experiments—experiments that would, in a theory neutral way, establish the truth of a scientific theory. Marburg philosophers emphasized that even the most primitive experimental results—measurements—presuppose a good amount of “theoretical” machinery: not only mathematics, but even physical laws. Cassirer cited Duhem in support (1910: Ch.4). Duhemian underdetermination of scientific theory by experience showed, Cassirer believed, that there is no given: no autonomous layer of self-authenticating experiences.