elendil wrote:infinite numbers? ridseard is our resident mathematician, so he should weigh in on this. however,
, in the order of is-ing, i think there's only one number = 1. whatever is, is a 1. therefore, there can't be an actually infinite number, since 1+1+1... at any given moment always adds up to a definite number = a finite number, limited. number is a description of limitation, at least in the order of is-ing, so infinity doesn't apply to number in that sense. i know mathematicians speak of infinite numbers, but i think they're using the term in a different manner. perhaps, potentially infinite, but not actually infinite, which is a contradiction in terms.
First of all, the thing designated by a sideways "8," commonly called "infinity," is
not a number. It is just a symbol used (mostly) in calculus to indicate that a quantity or process is unbounded. I.e., there is no bound on how large it can get.
A transfinite number, on the other hand, is an actual number, as concrete and definite as the usual finite numbers like 3, 17, 1578943, etc. Essential to the set-theoretic approach to numbers is the concept of cardinality. For example, a set is said to contain 5 elements (or have a cardinality of 5) if it can be put into one-to-one correspondence with the set consisting of the numerals 1,2,3,4,5. I.e., the elements in the set are counted and found to be 5. Transfinite cardinal numbers are also used to "count" how many items are in a set. For example, if a set can be put into one-to-one correspondence with the set of all natural numbers (1,2,3,...,etc....), then it is said to have a cardinality of
aleph-nought (designed by the first letter of the Hebrew alphabet with a "0" subscript). Lots of sets contain
aleph-noughtelements, such as the set of all positive and negative integers, the set of all even integers, and the set of all rational numbers. The one-to-one correspondences of these sets with the set of all natural numbers are very easy to set up, but a little beyond the scope of a C&F post. At first it seems as if the set of all natural numbers should be twice as large as the set of all even integers, but in fact these two sets are exactly the same size, both having the same cardinality. This is a characteristic of infinite sets: a proper subset may have exactly the same number of elements as the whole set. Another (larger) cardinal number is the number of all real numbers (all possible numbers, including infinite non-repeating decimal numbers), called
C (the number of the continuum). It is very easy to see toat
C is strictly larger than
aleph-nought. However, last time I messed with set theory (many years ago), it was not known whether
C is the next higher transfinite number after
aleph-nought (i.e.,
aleph-one). The conjecture that
C =
aleph-one is called the "continuum hypothesis."
There are a lot of popular books which explain all this a lot better than I can. I mainly just wanted to convey the idea that transfinite numbers are very definite, concrete mathematical objects. There is nothing at all wishy-washy, ambiguous, or mysterious about them.