 A third feature which is often regarded as defining of logic is its (alleged) epistemic primacy. Primitive logical notions can be grasped without relying on non-logical notions; and logical truths, if knowable, can be known independently of non-logical truths. Assume, for instance, that certain set-theoretic notions or truths must be regarded as extra-logical. Then our grasp of the primitive logical notions, or knowledge of logical truths, cannot depend on or involve any of this set-theoretic material.