 This theory is a proposal of ours, which elaborates on a suggestion of Rudy Rucker. We (and many others) have observed that of all the orders of infinity in Cantor’s paradise, only two actually occur in classical mathematical practice outside set theory: these are \(\aleph_0\) and \(c\), the infinity of the natural numbers and the infinity of the continuum. Pocket set theory is a theory motivated by the idea that these are the only infinities (Vopenka’s alternative set theory also has this property, by the way).