This is a monologue from the film Gladiator 2000:
We mortals are but shadows and dust, shadows and Dust, Maximus.
Could someone please explain this sentence? Apparently, the words dust and shadows are used figuratively. Does this but mean only?
"but" in your example is an old expression equivalent to "nothing but". Here are some examples of use:
In your example, Maximus is simply stating that human life is ephemeral. The word shadow is used as a reference to Plato's cave and the word dust may be a biblical reference:
And here, you can see the decline in use:
“In the life of a man, his time is but a moment, his being an incessant flux, his sense a dim rushlight, his body a prey of worms, his soul an unquiet eddy, his fortune dark, his fame doubtful. In short, all that is body is as coursing waters, all that is of the soul as dreams and vapors.”
― Marcus Aurelius, Meditations