I think that the second post means to use the word "imperial," not "empirical." Those are very different things.
The formula that is often used to describe the Europeans' motives is "God, gold, and glory." The Europeans went out for God (to Christianize the heathens in the rest of the world), for gold (to get rich) and for glory (to become famous for being the first to "find" one thing or another.
It is up to each person individually to decide which of these "g" words actually had the most to do with the Europeans' decision to go exploring.