And since pointer arithmetic is based on offset, it wouldn't make sense for C to use anything other than 0-index. But mathematical languages aren't focusing on mapping the hardware in any way, but to map the mathematics which already uses 1-index for vector/matrix indexing. You can see the relation of languages in [1].
If you want to write generic code for arrays in Julia, you shouldn't use direct indexing anyway, but iterators [2] which allows you to use arrays with any offset you want according to your problem, and for stuff that is tricky to do with 1-indexing like circular buffer the base library already provides solutions (such as mod1()).
[1] https://en.wikipedia.org/wiki/Comparison_of_programming_lang...
This is again just begging the question. When you want to refer to the initial element as the "1st", it is due to the established convention of starting to count from 1. The point is that the reasonining for starting from 1 might only be that: conventional, not based on some inherent logic.
But then I agree that there is no inherent logic, math is invented and not discovered, and you could define it any way you want. If we all had 8 fingers we would probably use base 8 instead of 10 after all.
It just so happens that this edge case of 0 things doesn't occur when we actually need to count something. Starting from 1 is kinda like head is a partial function (bad!) in some functional programming languages. Practicality beats purity.
f = v0 + x
f = v1 + x
Those are the same equations right? Sure, but when I see v1 I'm not really sure what it is or could be, vs if I saw v0 I can assume it may be the initial velocity when I can look up.