The counting numbers were probably originally poems.

When you count, you recite a memorized series of words while pointing to things one after another. In other words, you're doing the same thing children do when they do "Tinker, tailor, soldier, sailor" or "Eeny, meeny, miny, moe." In many languages, the counting numbers even have poem-like structures of rhyme and alliteration. This is particularly obvious in Japanese (as I discovered when we had to chant the On numbers while doing karate exercises; the Kun numbers are even more structured), but you can see it in English (o, t, t, f, f, s, s), Russian (syem, vosyem, dyevyat, dyesyat), and various others.

What's more likely -- that early people first came up with abstract words meaning things like "seven" and then invented counting, or that they began with tinker-tailor style counting and then the words used in the rhyme came to represent abstract numbers, much as do-re-mi developed out of the lyrics to a hymn? My money's on the latter.

I wonder if the original meanings of any of the counting rhymes can still be reconstructed this late in the day?