Zeno’s argument is grounded on the premise that space is infinitely divisible. One can argue that the flaw in Zeno’s argument lies precisely in this premise (that this premise is false) and that the rest of his argument is fine. I think that’s John’s position.
My position, however, is that even if we accept that space is infinitely divisible, Zeno’s conclusion does not follow. In other words, his argument is logically invalid.
What Zeno has shown is that you cannot cross an infinitely divisible distance by following Zeno’s algorithm. Zeno’s algorithm consists of making sure that each one of our steps is equal to one half of the remaining distance. This is where I agree with him. You can’t cross a path if you’re trying to walk this way (in the same exact way you can’t cross a path if you’re simply standing in one place.) However, he goes further than this, as he takes this to mean that no other algorithm exists that can allow us to cross an infinitely divisible distance, which means that no motion is possible if space is infinitely divisible. That’s where I disagree.
I argue that one way one can cross an infinitely divisible distance is by making sure that all of our steps are equal in size. If each each one of our steps is (1cm) in size, and if we’re crossing a distance of (1m), it will take us exactly (100) steps to cross it. However, if space is infinitely divisible, this means that (1cm) consists of an infinite number of points, so in order to make a step that is (1cm) in size, one has to cross an infinite number of points.
The question is: is this possible?
The answer depends on one’s definition of the word “infinity”.
Depending on how one defines the word “infinity”, the answer can be either “Yes” or “No”.
If the meaning of the word “infinity” is captured by the contradictory statement “A number greater than every number (including itself)” (Sense A) then one cannot visit an infinite number of points because regardless of how many points one visits there is still more points to visit.
However, if the meaning of the word “infinity” is captured by the statement “A number larger than every integer” (Sense B) then it might be possible to visit an infinite number of points since there is more than one such number. A number greater than every number including itself is only one such number. If the number of points is equal to some other number greater than every integer (not the one greater than literally every number) then one can cross all of the points.
The word “infinite” in Sense A is not the polar opposite of the word “finite”. In other words, if something is not infinite in Sense A, it does not mean it is finite. It might actually be infinite in Sense B.