Yafet Erasmo Sanchez Sanchez,
"...how does the zero number fit with the idea of number if there is nothing to count?"
I can't think of any case where zero is a number. If I am to make sense of zero it is not as a number but as a word indicating that I have not yet begun to count anything. If zero appears on a line with positive numbers to the right and negative numbers to the left, it remains a point of origin where I have not yet begun to count. If I count three units to the right and then reverse my direction and count five units to the left, I pass zero but ignore it in favor of the number three. In other words, zero doesn't exist as a part of the act of counting. The useful function of zero is as a placeholder so that I do not need to be personally located at a particular place in order to start counting from that location. The zero sometimesrepresents me standing stationary or is my marker for where I am imagining I am standing stationary. I could of course be speaking on behalf of another object other than myself.
"Also, do you have any insights about ordinal arithmetic? There certainly we are talking about "counting" in some sense. However, it is infinite counting which I am not sure is easy to represent with physical things. What are we counting then?"
No I don't, but, I do know that we receive all information from a storm of photons impacting upon us. Those photons along with all the other photons in the universe add up to a countable number. Furthermore, each photon delivers an incremental measure of change of velocity of a particle of matter. The photons are tiny bits of information. Out of that wild mix of photons arriving from innumerable sources, we know by innate means how to discern patterns of importance to us. Those patterns form in our minds. While they are there, we can imagine that they are continuous and perhaps even infinite, but, in no case did those photons originate from a source that is either continuous or infinite. My point is that there is much math that is useful to apply to the patterns that we imagine in our minds and then there is the math that applies to the source of our original information. I think that those maths are not the same maths.
"...You encourage me to read your essay... ."
That would be great, but, it might appear to be one very wild ride. :) I can't be right unless theoretical physics is wrong beginning with its treatment of mass in f=ma. After I eliminate the indefinable status of mass, there are great changes in store. I have publicly written about and presented many of those changes. I think I am on the correct path, but, let me know what you think. Thank you.
James Putnam