The one alone, the universal singleton, the “first” “counted thing”, God, the solipsist, alone … the monad!
We would think that there is one such thing. But without another to identify it, we cannot entertain the possibility of the one alone being “one” thing.
The monad is uncountable. It is uncountable in a way that places it beyond the greatest infinity … if we care to pamper the latter as a rival.