No one will deny the fact that, slaves in Greece played an importand part in the evolution of philopsophy, art, science ect but there are varius diferences between the modern concept of slavery and the Greek one.

American slavery-
“Slaves were held pro nullis: pro mortuis, pro quadrupedibus; they had no head in the State; no name, title or register; they were not capable of being injured, nor could they take by purchase or descent; they had no heirs, and could therefore make no will; exclusive of what was called their peculium, whatever they acquired was their master’s; they could not plead or be pleaded for, but were excluded from all civil concerns whatever. They could not claim the indulgence of absence reipublicæ causa: they were not entitled to the rights and considerations of matrimony, and therefore had no relief in case of adultery; nor were they proper objects of cognation and affinity, but of quasi-cognation only: they could be sold, transferred, or pawned as goods or personal estate, for goods they were, and as such they were esteemed; they might be tortured for evidence, punished at the discretion of their lord, or even put to death by his authority.” (Taylor’s Elements, p. 429.)


and a Greek version "A chance to earn back his freedom was given to any Athenian slave, for quite frequently he was paid for his work. This gave him a chance to also save his money. They had the right to put up a subject of concern on the "pnix" and debate it freely.After he had earned back his freedom, he became a resident alien. However, the people who stayed slaves in Athens had miserable lives. In groups, they were sent down to mine at Laurium, working in a very unhealthy environment.(Greek history)"

So if we concider our selves today we will notice that in fact we are "slaves" in a sence. We all work for someone or somewhere and get paid, although we are given the right to vote a lot of us don't, joining the army is mandatory to most countries; so very few people join, only the rich own property; the rest we just rent. In a lot of aspects we can see that today's "free" man is more a slave than the slaves of Ancient Greece and the crazy thing about this, is the fact that we are made to be like that from the same social system that we have created.
And ask your selves now "Is there any real progress in ART, Philosophy, Architecture or we just don't have the time to pursue anything else other than our jobs and trying to live a good life in the democratic "idea"? and we have also become slaves even today."