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Cantor’S Paradise and the Parable of Frozen Time

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Cybernetics and Human Knowing. Vol. 16, nos. 1-2, pp. xx-xx Virtual Logic Cantor’s Paradise and the Parable of Frozen Time Louis H. Kauffman1 I. Introduction Georg Cantor (Cantor, 1941; Dauben, 1990) is well-known to mathematicians as the inventor/discoverer of the arithmetic and ordering of mathematical infinity. Cantor discovered the theory of transfinite numbers, and an infinite hierarchy of ever-larger infinities. To the uninitiated this Cantorian notion of larger and larger infinities must seem prolix and astonishing, given that it is difficult enough to imagine infinity, much less an infinite structure of infinities. Who has not wondered about the vastness of interstellar space, or the possibility of worlds within worlds forever, as we descend into the microworld? It is part of our heritage as observers of ourselves and our universe that we are interested in infinity. Infinity in the sense of unending process and unbounded space is our intuition of life, action and sense of being. In this column we discuss infinity, first from a Cantorian point of view. We prove Cantor's Key Theorem about the power set of a set. Given a set X, the power set P(X) is the set of all subsets of X. Cantor's Theorem states that P(X) is always larger than X, even when X itself is infinite. What can it mean for one infinity to be larger than another? Along with proving his very surprising theorem, Cantor found a way to compare infinities. It is a way that generalizes how we compare finite sets. We will discuss this generalization of size in the first section of the column below. In the world of Cantor, if X is an infinite set, then X < P(X) < P(P(X)) < ... in an unending ascent into higher infinities. Set theory in the classical mode is a theory about forms and structures that are eternally unchanging. When we speak of the set of integers or the set of all sets they are assumed to exist in eternity. When set theory is propelled into the world of Time, a different and equally beautiful structure emerges. This temporal structure is the domain of performative language. Performative language is language whose very utterance commits the speaker to a process and a contract for action. When we speak of all sets or all distinctions, then the very act of speaking creates new sets and new distinctions. The only eternity here is in the moment, and time is an integral part of the structure of our acts and our mathematics. 1. Email: [email protected] 2 Louis H. Kauffman We are led into a speculation about the nature of time. With Cantor’s Infinite, the infinity is frozen time. Temporal process is an intimation of infinity. Infinite sets are inherently self-referential, containing copies of themselves within themselves. (Infinite sets are like those fractal pictures where a person reads a book whose cover shows a person reading a book whose cover shows a person reading a book ...) Time and self-reference (an act that plays itself out in time) work together in a balance and movement that is the life of awareness. In this essay, we introduce the set Aleph of all sets whose members are sets. Aleph is the simplest of all the concepts of sets. Aleph is the concept of sets whose members are sets – all the way down to nothing at all. Aleph is the concept of making sets from previously created sets, with the creation based on emptiness. But surprise! Aleph is its own power set. After all, any element of Aleph is a set whose members are sets in Aleph. And so any member of Aleph is a subset of Aleph. Similarly, as soon as you make a subset of Aleph, that set becomes a member of Aleph. This is the performative aspect of Aleph’s creation. So Aleph = P(Aleph). Therefore P(Aleph) is not greater than Aleph. Aleph is a counterexample to Cantor's Theorem. How can this be? Some have said that Aleph is not a set. We say that Aleph is too great to be a set that exists only in eternity. The reality of Aleph is a continual process of creation. No sooner have you written down a fragment of Aleph, then this fragment can be collected to form new members of Aleph. No matter how great Aleph becomes, she is always greater than that. Aleph is the eye of the storm where thought can think itself and the world begins. When thought thinks itself and awareness becomes aware of awareness, then action occurs in the world and action being energy-through-time is physical. Pure thought and physicality are one in a creation that is a temporal eternity. II. Cantor’s Paradise How did Cantor find this infinite hierarchy of infinities? We are all familiar with the infinity of the counting numbers 1,2,3,4,5,6,.... Mathematicians call these the natural numbers and write N = {1,2,3,4,...} to denote the entire set of natural numbers. Certain subsets of the natural numbers are key objects for the general concept of counting. For example, let n denote the set of the natural numbers (and zero) up to n- 1. Thus 0 = { } (the empty subset) 1 = { 0 } 2 = { 0, 1} 3 = { 0, 1, 2 } Cantor’s Paradise 3 and so on. n is a set-theoretic yardstick for sets with n elements. A set S is said to be finite with cardinality n if S can be put into one-to-one correspondence with the special subset n of the natural numbers. For example { A, B, C } has cardinality 3 since it can be matched one-to-one with 3 = { 0, 1, 2 }. One-to- one correspondence captures the essence of counting. We have all learned to grasp this concept, and we easily move from two arms to two fingers to two parents and understand that these are all instances of the number two. In mathematics we find it easier to understand a number as a relationship than to understand a number as a thing. The essence of 3 is not the conventional notation for three. But by making a standard instance of 3 in the set 3 = { 0, 1, 2 } we provide the possibility of matching to any and all occurrences of three. In so doing we weave a relationship between the general (all possible instances of three) and the particular instance of three that we have chosen for our standard of comparison. Now you might start to think that this set theoretic discussion of numbers is a wee bit circular! First I said that we would assume familiarity with the numbers 1, 2, 3, ... and then I asked you to take the set n = { 0, 1, 2, 3, ... n-1 } as a yardstick for the number n. But this is not a circularity. It is what we really meant by the number n as a symbol (like 1 or 2 or 3). The number n as a symbol is a special sign that denotes that place in the sequence of counting where the n-th count has happened. Thus when you count to ten, you reach the symbol 10 at the point when you have counted ten times! The symbol 10 denotes the achievement of a 1-1 correspondence between your acts of counting and the elements of the set 10 = { 0,1,2,3,4,5,6,7,8,9 }. Each number n is a name of an ordered counting sequence that starts at 0 and ends at that number n-1. We determine the cardinality of a set of things by matching them with some standard set of things. Our process of “counting in order” facilitates such making of correspondences. Thus, for finite numbers, the concepts of cardinality and order are intertwined. We understand how to make 1-1 correspondence through our experience in counting. Numbers are used for the dual purposes of cardinality and counting. Something strange happens when we attempt to count infinite collections. First of all, it becomes impossible to just speak 1,2, 3, ... until we have chanted the names of all the natural numbers. We do have names for them, but we do not have the time to make a complete count. In fact I would wager that very few readers of this column have ever counted even to one thousand, saying each natural number in the sequence 1,2,3, ..., 999, 1000. While we cannot physically count infinite collections in order, we can make significant 1-1 correspondences. For example, let E denote the even natural numbers so that E = { 2,4,6,8,10,... }. Then there is a 1-1 correspondence between N and E given by associating the number n in N to the number 2n in E. This is a perfect matching between the elements of N and the elements of E. Every element in N is matched to a unique element in E and every element of E has a mate in N. 4 Louis H. Kauffman N = { 1, 2, 3, 4, 5, ... } E = { 2, 4, 6, 8, 10 , ...} We shall say that any two sets X and Y have the same size (cardinality) f there is a 1-1 correspondence between the elements of X and the elements of Y. Cardinality for infinite sets is a natural generalization of size for finite sets. We have just shown that N and E have the same cardinality and hence the same (generalized) size. For example, you will agree that {a,b,c} and {1,2,3} are sets with the same number of members, while {1,2,3,4} is a set that is larger than {a,b,c}.
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