sure, i'd go one step further and note that there are no absolute certainties, so those free variables always exist, even implicitly. in that vein, most threshold numbers like that should at least come with uncertainty bounds (damn lies and statistics).

said another way, outside of math and formal logic, real-world arguments resolve at best to "if the data is indeed as argued, then it's most likely true" (perhaps gödel is relevant here, as @marcinzm referenced downthread[1], another citation!).

[1] https://news.ycombinator.com/item?id=23899111