Could we also speak of Scientism here? Where do we draw the dividing line? Is the main difference that scientist-scientists use science as a rhetorical tool to realise their goals, as it has become common in debates to underpin everything ‘scientifically’ with research and statistics?
Titus --
My first response would be to point out the reason that you are asking the question -- No one really has a clear definition of what "Scientism" means, any more than anyone can give a precise answer to what "Humanism" means.
Unlike with Epicurus, which we can trace back more or less accurately to the writings of a single group of people, "Scientism" is an attitude that has no clear definition. If someone suggestions that a particular doctrine is or ought to be considered a part of Epicurean philosophy, they can compare that assertion to the preserved doctrines of Epicurus and make their own determination of whether Epicurus would have agreed.
But the Epicureans did not call their philosophy "hedonism" or "pleasure-ism," not did they call it "canonicsism" or "empiricism." They were aware that they were teaching an entire world-view of which adherence to the authority of the senses is critical, and which deduces that pleasure is the ultimate goal of life, and in which "virtue" is important, but they likewise denounced "placing the cart before the horse" and elevating virtue or reason or any other "tool" above the ultimate conclusions of the philosophic approach.
So from that point of view I would assert that we need to apply all of the cautions that Epicurus applied to "virtue," and even to the feeling of pleasure in that we do not always choose what is immediately pleasurable, to emphasize the point that every time we elevate a tool -- even such important tools as pleasure and friendship" into the place of the ultimate conclusions, then we are ignoring the thrust of Epicurean philosophy. To elevate "science" as an end in itself would be as wrong as elevating "reason" or "logic" or "friendship" or "wisdom" as ends in themselves, which Epicurus clearly warned against doing.
And to the extent it is possible to make any sense of the words "Scientism" or "Humanism," that's exactly what those terms are doing -- setting up a standard which Epicurean philosophy would clearly hold to be false.