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In set theory [1], two sets are considered to have the same cardinality, if a one-to-one correspondence can be set up between them. Cantor has shown that the powerset of a set can never be put into one-to-one correspondence with the original set itself, even when the given set is infinite. What this means is that we can go on taking powerset of powersets to produce larger and larger sets. Thus starting with ℵ0, the set of natural numbers, we can repeatedly take powersets and end up with an infinite sequence of infinite sets of ever increasing size. If we use the notation 2ℵ0 for the powerset of ℵ0