#124
"Also worth noting that Cantor eventually went nuts poor lad."
He suffered from depression.
#128
"This is
math problem, not a real world problem."
Mathematics is an abstract language applied to real world examples everyday.
It's the verification tool of science.
Beginning with counting, it was developed for practical needs, similar to time.
The concept of 'infinity' has been applied to a real world problem, the Hilbert Hotel with rooms and guests. The difficulty is solving the problem using methods developed for a world of finite elements when they don't apply.
Cantor attempted to define transfinite sets as an extension of the number system.
"I say of a set that it can be thought of as finished (and call such a set, if it contains infinitely many elements, "transfinite" or "suprafinite")
if it is possible without contradiction (as can be done with finite sets) to think of
all its elements as existing together, and to to think of the set itself as
a compounded thing for itself; or (in other words)
if it is possible to imagine the set as
actually existing with the totality of its elements."
What he defined was a contradiction of terms, a thing without a boundary yet complete.
He was unsure if it was possible (red).
The constructivist view is, if a process requires an 'infinite amount of time to complete', then it never happens.
If a motion begins at t=0, then after moving a distance x at t=1, you have additional distance to move greater than x! I.e., you cannot make any progress.
You cannot approach 'infinity'.
#134
"Now, back to why phyti thinks the diagonal is incompatible with something and why
that matters ..."
Draw a 1 unit vector vertically, and a 1 unit vector at 45°. Note they are not equal if applied to an object. Vectors have magnitude and direction.
When Cantor defined the diagonal sequence, it became 2 dimensional with a 45° orientation, when all other sequences were horizontal and 1 dimensional.
He is comparing 2 different classes of sequences.
Here is a simple example. Sequence A is transformed to sequence B per the Cantor method. Both coexist if 1 dimensional. If A is oriented to a diagonal, there is a contradiction at the diagonal for every u coordinate for B. When v=u, the coordinate can't be 2 different symbols simultaneously. The example is a finite list, thus the problem is independent of the length, finite or not.