Demurrer challenges pleading sufficiency, testing whether alleged facts can legally support a claim before answering. Demurrer challenges the legal sufficiency of a pleading by asserting that, even if the alleged facts are true, they fail to state a claim for relief. It is functionally analogous to a motion to dismiss in many jurisdictions, though still used in some; historically it was classified as general when attacking substance and special when attacking form, with the latter requiring specific identification of defects.