There has recently been much-needed critical discussion of the current Anglo-American philosophical canons, but not as much consideration of their nature and purposes. In this chapter, the author discusses what philosophical canons are and argues that they are social practices, and in particular, social practices of enforcing rules. On this account, canons are constituted by dogmatic practices, no matter what their makeup is. Assuming a view of philosophy as unrestrictedly critical and eschewing dogmas, the author argues that canons practically undermine the ultimate point for which they exist. The argument proceeds as follows: the author critically considers what purposes a philosophical canon can have for various stakeholders, arguing that the ultimate end of a philosophical canon is better philosophy (however that is to be understood). Building on Luca Castagnoli’s work on self-refutation in ancient philosophy, the author explains what it means for a canon to be practically self-undermining. Putting all these pieces together – a particular canonical view of philosophy, a highly general analysis of the ultimate point of philosophical canons, my account of canons as practices of enforcing rules and the notion of being practically self-undermining – renders the conclusion that any philosophical canon is practically self-undermining. This is not a complete argument for being a canon-shredder (as opposed to a canon-keeper or a canon-expander); but the author’s analysis of canons is a partial argument for being a canon-shredder, that is for getting rid of canons rather than either keeping or expanding them.