Although superficially the adverb of
science, this has a special meaning when incorporated into phrases like:
"this product was scientifically proven"
and
""well, scientifically speaking..."
In this sense it is sufficiently vague that you cannot be sued or questioned on the details, but it lends an air of superiority and sober judgement to the undertaking. Scientifically is, of course, the opposite of "Simianically" - as in "this product was simianically proven" (was tested by monkeys) or "simianically speaking..." (according to my troop of infinite monkeys, who communicate only through typewriter).
That is not to say that monkeys aren't scientific...