Christian (though not right-wing fundamentalist) apologist goes fishing:

What does “greatest” even mean? The person who published the most, or received the most awards, or who made the most money, etc?

“Scientist” is also a suspect term. But if you mean one who impacted knowledge about the real world the most, then I say:

Zacharias Janssen.

— freetoken fights fecking fascists (@freetoken) November 13, 2021