For those championing the concept of the actual infinite in mathematics, and physics, set theory comes to their rescue. In this paper, I will refute a major theorem, or alleged theorem purporting to show that there are different levels of infinity regarding sets, Cantor’s power set theorem. Wilfred Hodges, “An Editor Recalls Some Hopeless papers, “Bulletin of Symbolic Logic, vol. 4, no 1, 1998, pp. 1-16, says while gloating about cranks that attempted to refute Cantor, “None of the authors showed any knowledge of Cantor’s theorem about the cardinalities of power sets.” (p.2) So, let’s examine this. Cantor’s power, or the axiom of powers, states that for any set S, there exists a collection of sets Power (S), which contain in its elements, all of the subsets of the given set S. thus, for example, if S = { a, b }, then Power (S) = { ϕ, {a}, {b}, {a, b}}, where “ϕ” is the empty set. As the sets get bigger, so does the power set. In fact:
“If S is a finite set with |S| = n elements, then the number of subsets of S is |P(S)| = 2n. This fact, which is the motivation for the notation 2S, may be demonstrated simply as follows, First, order the elements of S in any manner. We write any subset of S in the format {γ1, γ2, ..., γn } where γi , 1 ≤ i ≤ n, can take the value of 0 or 1. If γi = 1, the i-th element of S is in the subset; otherwise, the i-th element is not in the subset. Clearly the number of distinct subsets that can be constructed this way is 2n as γi ∈ {0, 1}.” “Cantor’s diagonal argument shows that the power set of a set (whether infinite or not) always has strictly higher cardinality than the set itself (informally the power set must be larger than the original set). In particular, Cantor’s theorem shows that the power set of a countably infinite set is uncountably infinite. The power set of the set of natural numbers can be put in a one-to-one correspondence with the set of real numbers.”
https://en.wikipedia.org/wiki/Power_set
