Finally got a little bit of time to reply...
I feel like we can agree on the basic premise that universal human rights, as we understand them today, came from Enlightenment thinking. From what I can tell so far, you and can agree on the fact that nothing like "universal human rights" is something that existed in ancient societies, like Egypt, Greece, or Rome. (The Greeks famously didn't have a word for "rights" although this thesis can be debated...) And I think you and I can agree that the middle ages in Europe saw little to advance the idea of universal human rights.
I would say that the idea of UHR saw their most clear expression in the Enlightenment era, but that most of the building blocks predated that era and the middle ages were important in this regard, and theology and canon law were significant factors in this.
William of Ockham proposed that humans have both political and property rights that derive from natural law. Texts like
Defensor pacis by Marsilius of Padua outline clear theories of secular governance and popular sovereignty.
Even with colonisation of the Americas by the Spanish, there were concepts of the Aztecs having rights that derived from their humanity:
Bartolomé de las Casas - Wikipedia
Beyond this, there were many developments in this period. Now obviously these were not necessarily the dominant view of either power holders of the time or common people, but these were developments that advanced towards a world where UHR could be articulated.
So I think at least some medieval thinkers had a primitive concept of UHR, and these certainly advanced the idea of human rights closer to its modern conception.
Inasmuch as the Enlightenment was a return to the Greek thinking of this period, it is exempted for consideration of being based in Christianity. The dark ages, with all its witch-burnings and paranoia about heretics and Satanists "cursing villages" and "spoiling dairy"... THAT is much more in line with the value-repellant, truth-repellant jism of Homeristic paganism than it is with Socrates or Plato.
The poor medievals always get a bad rap
Witch crazes were Renaissance rather than Medieval. For most of the medieval period the church position was that witches didn't exist.
And they emerged in a time of great turmoil in the context of war, plague, and crop failures and famines caused by "Little Ice Age", as well as the Reformation/counter-reformation. But that's another topic altogether.
To summarize, we should be aware of Christianity's influence in the Enlightenment. But at the same time, it is where thinkers began to seriously challenge Christianity from a completely secular (ie. rational and empirical) vantagepoint. I reject the idea the all Enlightenment morality is reducible to Christian morality. But, at the same time, I admit that much Enlightenment morality (maybe even the majority of it) was rooted-in, or inspired by, Christian morality.
A secular age by Charles Taylor is a fascinating analysis of the social and intellectual changes that led to the point where an "exclusive humanism" became possible, although at 800 pages it's not really a casual, light read.
This blog summarises each chapter pretty well though:
Posts about Charles Taylor written by Julian
coffeewithkierkgaard.home.blog
But let's look at where his ideas lead us conclusion-wise. There is a fundamental difference between body and soul. Therefore, the scientists and mathematicians ought to observe the world as a mechanistic thing. And they needn't be bogged down with notions of spirits or souls. Let the clergy tell us about souls and how they might achieve salvation; let the scientists measure the world as a mechanistic thing without much concern for souls. That's kinda how contemporary science works. Science doesn't bother itself proving or disproving gods. It works solely in empirical matters. Granted, Descartes was a rationalist-- not an empiricist-- but his basic notions, working within the sphere of rationalism, carried us into the age of empirical thought.
One interesting argument is that the move towards empiricism and the experimental method in science had some of its foundations in the Biblical Fall narrative (which also underpins a progressive teleology to history):
The experimental approach is justified primarily by appeals to the weakness of our sensory and cognitive capacities. For many seventeenth-century English thinkers these weaknesses were understood as consequences of the Fall. Boyle and Locke, for their part, also place stress on the incapacities that necessarily attend the kind of beings that we are. But in both cases, the more important issue is the nature of human capacities rather than the nature of the Deity. And if the idea of a fall away from an originally perfect knowledge begins to decline in importance towards the end of the seventeenth century, it nonetheless played a crucial role by drawing attention to the question of the capacities of human nature in the present world...
One of the first texts that [Francis] Bacon would have had to contend with was the ‘Organon’, a collection of Aristotle’s writings on logic. All undergraduates were expected to become familiar with its contents, and until well into the seventeenth century university statutes prescribed monetary penalties for those guilty of transgressions against Aristotle’s logic.
Bacon’s early resistance to the Aristotelianism he encountered at university and his later ambition to establish new foundations for learning are both evident in the title of what is probably his best known philosophical work: Novum organum – (The New Organon, 1620). At this point it should be unnecessary to labour the fact that Bacon has a conception of natural philosophy as an enterprise devoted to a recovery of Adamic knowledge of nature and dominion over it.
Each of the two sections of the Novum Organum concludes with an injunction to recover the dominion over nature that was lost as a consequence of the Fall. As for the impediments to this recovery, Bacon saw in the long-standing tradition of Aristotelian logic an implicit recognition of the fact that ‘the human intellect left to its own course is not to be trusted’. But Bacon was convinced that the purveyors of logic had systematically misidentified the nature of mental errors and the means by which they were to be corrected. The champions of the old Organon ‘have given the first place to Logic, supposing that the surest helps to the sciences were to be found in that’. In Bacon’s judgement, ‘the remedy is altogether too weak for the disease’. The impotence of logic in the face of the human propensity for error could be attributed to two factors. First, the logicians had simply underestimated the extent of the problem they were seeking to rectify.154 ‘The root cause of nearly all evils in the sciences’, Bacon wrote, is that ‘we falsely admire and extol the powers of the human mind.’ As a consequence, ‘we neglect to seek for its true helps’.155 Second, not realising that error stems from multiple failures of the human mind, they had prescribed a single generic remedy.156
In order to arrive at a true interpretation of nature, Bacon insists, we need to begin with an understanding of human faculties and their limitations. In the Novum Organum, then, Bacon identifies the senses, memory, and reason as the faculties involved in knowledge, and seeks specific ‘ministrations’ or ‘helps’ to heal their inherent infirmities.157 These infirmities, which for Bacon ‘have their foundation in human nature itself’, are referred to as ‘the idols of the tribe’, the first category of four ‘idols of the mind’ to which Bacon attributes the errors of human knowledge.158 For Bacon, the deficiencies of the senses provide the first occasion for error: ‘By far the greatest hindrance and aberration of the human understanding proceeds from the dullness, incompetency, and deceptions of the senses.’159The senses, which are ‘infirm and erring’, fail us in two ways. Sometimes they provide no information; sometimes they provide false information...
Bacon believed that a better ‘help’ for the senses was experimentation: ‘For the subtlety of experiments is far greater than that of the sense itself, even when assisted by exquisite instruments.’" Peter Harrison - The Fall of Man and the foundations of modern science
lenty of insights there. But of course, I'll focus on what I disagree with because that's what'll clarify things the most. it is inaccurate to say that a return to "classical" values is a return to "ancient pagan values." We aren't talking about returning to Homer's Greece. We are talking about returning to the "classical values" as espoused by Socrates, Plato, Aristotle. All three of these figures challenged the idea of "cyclical/chaotic, non-universal, tragic, capricious gods, no real concept of secular/religious."
You make a fair point that we should distinguish between the pre-Socratic era, and Plato and Aristotle (who were both significant influences on Christianity which certainly drew heavily from Greek philosophy).
I still find it hard to see it primarily as a return to classical values though, while accepting that Greek philosophy was certainly part of the mix of ideas percolating at that time.
Aristotle saw humans as fundamentally unequal, some even natural slaves as they lacked reason and thus were incapable of living a virtuous life.
Greek virtue ethics and the idea that the pursuit of wisdom is an aid to virtue, also don't seem a good fit for the more utilitarian Enlightenment ethics, where the world can be bent to human will, and the pursuit of knowledge is to advance the progress of humanity.
As you note, later Greek thinkers may have had some concept of progress, but I feel this is of a somewhat different nature:
Progress - societies can build up knowledge and make improvements within the limitations
a teleological Idea of Progress - 'humanity' is a moral agent that inexorably trends toward becoming a better version of itself (whether driven by Divine Providence or "reason")
I'd say the Idea of Progress as driven by human reason is the single most fundamental characteristic of Enlightenment thought in that it underpins both the liberal and illiberal streams.
Also, do you think that they had a clear concept of secular and religious as 2 distinct domains? I'm not sure that's something I can see, although it could be said that some schools of thought had an implicitly secular, in the sense of naturalistic, view of the world.
Innate equality and rights deriving from a common humanity rather than membership of a group still seem to me to be more of a secularisation of a certain kind of theology.
