RoughRomanMemes

Sure thing! Effectively, much of it comes down to the core political orientation of Greek polities vs. Rome. Greek city-states were intensely insular; slaves, being largely seen as 'outsiders', were essentially condemned to a degraded state indefinitely. For that matter, resident noncitizens were also condemned to that state in perpetuity - and in many Greek polities, mixed citizen-noncitizen marriages also would not produce citizens, but rather resident aliens. You see this pattern as far afield as Greek-ruled Ptolemaic Egypt, wherein only Greeks were permitted 'real' citizenship in the polity, and all others were offered only a degraded form.

This permanent alienation of slaves meant that the already-harsh-and-short life of a slave was additionally condemned by both the disinterest of their masters in granting them freedom, and in the result if they did get their freedom of being part of a hereditary second-class. This is further reinforced by Greek writing from thinkers like Aristotle, who mused that some people were, by their nature, simply born to be slaves, being both more useful and more happy in that condition. While there was not a 'racial' component as we would recognize it, this widespread idea cemented the hierarchy of Greek slavery.

Roman slavery was harsh and cruel, as all forms of slavery, but it has several distinctive features that are unusual.

First, the aforementioned difference in polities - Rome was founded, semi-legendarily, as a city of exiles and criminals, and in part for that reason, always had a bit of a 'loose' attitude towards accepting new individuals as citizens, even if they were quite snobbish about accepting communities. If you schmoozed with the right people, or if you were rich, or if you did someone a suitable favor, even in the Republican era, you could become a citizen. This seems small, but given the very 'closed caste' attitude of many other contemporary polities, it's positively welcoming. Your master may be an utter bastard, but once you're free, you're part of a world where social mobility is possible. A foreigner can become a Latin citizen; a Latin can become a Roman citizen.

Second, and related to the first point, Roman slaves (belonging to Roman citizens) were, themselves, granted citizenship upon being freed, with some disabilities (notably, they could not run for office). Not only that, but they were considered one of their former master's cliens, the people - including freeborn citizens - whom he had a social obligation to (that cut both ways, mind, but was non-negligible as a means of calling on the more powerful for favors). Their children, for that matter, would be full citizens without any disabilities - notably, the Emperor Pertinax was the son of a freed slave.

This meant that every slave who was freed was both a boon to the one freeing them - as the patron now has another citizen cliens who can assist them in political matters - and a potential social contact going forward, meaning one may wish to keep the beatings and degradation to a minimum to ensure goodwill, at least to slaves whom you may be thinking of freeing at some point. This may also seem small, but by applying simple self-interest to the issue of freeing one's slaves, it becomes more desirable from the point of view of the master than in Greek slavery, wherein a freed slave is just another of the marginal, politically irrelevant mass of resident aliens who lack the political power to support anyone's civic ambitions, and whom no decent Greek citizen would be caught dead consorting with in any case.

Third, Rome largely lacked the conception of slavery as an innate condition. People who were born slaves were seen as having shit luck, not coming into the world custom-made for chains. A slave, to the Romans, was considered a 'talking tool', that is to say, property to be used in any way one pleased the same as no one would question what a man does with his rake or his hammer; but also was only a social condition. A slave in the Roman conception was not much different than an impoverished laborer, save that a slave had no rights. As Julius Caesar once noted, all people innately and naturally desire freedom.

If your luck was shitty enough, you might end up a slave - kidnapped by bandits or roving marauders - or condemned for a suitably serious crime. Some of the earliest Latin literature - comedic plays (written by an ex-slave, funny enough) - involves slaves outwitting their masters, and rather than being condemned for it, it being seen as natural, normal, and amusing - precisely because to the Romans, slaves are just a social class. Being outwitted by someone in a different condition does not fundamentally upset the social order; it's just part of life.

For this reason, there is a certain level of sympathy offered to slaves in Latin writing. While there is no widespread abolitionism as we would recognize it, the Romans are more likely to see slaves as poor bastards stuck in a form of ultra-poverty rather than being in their 'proper place'. The rate of manumission in Roman society was extremely high, with some high-count estimates placing the lifetime rate of manumission at 50% - that is to say, half of all slaves would end up freed at some point in their life. This, I must emphasize, is a high estimate, but it is also a legitimate one based on the study of the available evidence, not just a random number.

Imperial and public slaves in particular were freed at extremely high rates, presumably as a means of incentivizing good work, and a large number of free provincials are noted as marrying imperial slaves precisely because imperial slaves expected to be given their freedom after a number of years of service, and were thus seen as 'upwardly mobile'. Many workers in semiskilled industries were slaves who later became freedmen, and then ran businesses of their own (often, themselves, employing slaves - starting the cycle all over again, lmao).

Fourth, the intense legalism of Roman society meant that contracts were applicable to slaves as well as free people. Slaves who made contracts with their masters could have those contracts legally enforced, rather than being purely at the whim of their master. While this certainly incentivizes masters to make no contract that they aren't certain they want to follow through on with their slaves, it also ensures that any such contracts gave slaves legitimate leverage. A curious example is the common use of slaves as a kind of 'limited liability corporation' - a slave would be declared the owner of a business venture, and because a master could not be held liable for their slave's actions, the business venture could not, by bad luck or bad decisions, imperil the investors' personal wealth, only their actual invested wealth. A slave in such a position was still liable to whatever cruelties their master inflicted on them, but also was legally possessed of ownership of a large amount of their owner's property, which is an excellent bargaining position to be in when looking for freedom, or even just better treatment. Slaves, for the reason of the intense legalism of Roman society, would also later acquire limited rights and protections (emphasis on 'limited').

Fifth, one of the recurring themes of early Roman society is the Romans finding out that other people do things better than them, pretty unambiguously. Many of the peoples the Romans conquered during the Republic were themselves more developed and civilized. Rather than associating slaves with the fur-wearing tribesmen far to the north, Romans saw slaves as possessed of a wide variety of skills and intellects. A slave, thus, may legitimately be your intellectual equal without impugning your status as a citizen, precisely because slavery lacks a cultural connotation of innate inferiority. Slaves were very often teachers, of both academic and practical subjects, precisely because slaves were just ordinary (if often foreign) people with a run of shit luck.

Sixth, slaves were considered part of the household - the familia. Rather than just being abstract property, there was a moral and spiritual component to the treatment of slaves, and it was expected that the ancestral spirits (lares, which the Romans took rather seriously) both included some of the household's past (deceased) slaves, and that the ancestral spirits expected respect from the household's present slaves, precisely because they were part of the familia. This is not a legal protection, but it is a cultural one, and it bears note.

Lest this go too far in playing apologetics for Roman slavery, I feel obligated to point out there was still intense classism and snobbishness in Roman society towards freedmen, especially rich freedmen, seen as nouveau riche. These points absolutely did not stop horrific treatment of Roman slaves, both domestic and industrial, which is recorded in great detail. Women assaulting their serving girls with hairpins, short-tempered men putting out a servant's eye with a stylus, slaves being whipped for circumstances out of their control or just sheer meanness of their owners, etc etc etc. Not even getting into the rampant and socially accepted sexual abuse of slaves by their masters.

Slaves in monocrop agriculture and mining had very little chance of being freed, and life was utterly miserable for both - and very short for mining slaves, who were estimated to live for six months after being condemned to the mines. As the Empire wore on, especially into the 3rd century AD, it absorbed more Hellenic ideas, including on slavery, though Hellenic thought never dominated the institution the way it did in native Greek societies. Slave suppression was a constant topic of the elite, including how best to isolate and break any potential 'troublemakers' - it was not simply detached and distant, but actively involved in the 'stick' as well as the 'carrot'. Brands, tattoos, scarring, chains and collars... if the Romans took seriously the idea of slaves as a social class instead of an innate quality, they also very much took seriously the idea of slaves as property instead of people with rights. And the Romans were not shy about such cruelties as crucifixion to keep any would-be rebellious slaves from 'causing trouble' (though even slaves had to go through the judicial system to be crucified, as crucifixion was considered an exceptionally harsh punishment).