Let's just pretend as if many of our present core western morals and values, wouldn't be considered heretic / blasphemous in strictly christian doctrine?
No idea what 'strictly Christian doctrine' is, but we can look at the history of how they emerged over many centuries often explicitly based on Christian doctrine
I think it is somewhat of a common public lie that our secular democratic morals and values emerged from, or are based on, christianity. I'ld rather say that they are based on humanism.
And where did humanism come from?
For many of the "values" / rights we take for granted today, people like to pretend as if they are derived from christianity... Totally ignoring that for the better part of western history under the rule of christian theocracy, those things would have been unthinkable. To the point of even earning you a death sentence.
The 'better part of Western history' didn't happen under a Christian theocracy, and these values emerged over 1500+ years.
People tend to forget that in large part, our humanistic secular democracies were born in large part out of kicking the church out of public life and government.
The separation of "church and state" (read religion and politics) emerged in a Christian context. It didn;t exist in pre-Christian Europe, and didn't exist in the majority of other belief systems either.
Going back many centuries to the conflicts between Emperor Henry IV and Gregory XII and Emperor Louis IV and Pope John XXII you get a division between secular and religious authority.
And scholars such as Marsilius of Padua:
The tract
Defensor pacis (
The Defender of Peace) laid the foundations of modern doctrines of
sovereignty. It was written by
Marsilius of Padua (Italian:
Marsilio da Padova), an Italian medieval scholar. It appeared in 1324 and provoked a storm of
controversy that lasted through the century. The context of the work lies in the political struggle between
Louis IV, Holy Roman Emperor and
Pope John XXII. The treatise is vehemently
anticlerical. Marsilius' work was censured by
Pope Benedict XII and
Pope Clement VI.
Defensor pacis extends the tradition of
Dante's
De Monarchia separating the secular
State from religious authority. It affirmed the sovereignty of the people and
civil law and sought to greatly limit the power of the
Papacy, which he viewed as the "cause of the trouble which prevails among men" and which he characterized as a "fictitious" power. He proposed the seizure of church property by civil authority and the elimination of
tithes. In his view, the Papacy would retain only an honorary pre-eminence without any authority to interpret the
scriptures or define
dogma.
Defensor pacis - Wikipedia
In
Defensor pacis, Marsilius sought to demonstrate, by arguments from
reason (in
Dictio I of the text) and by argument from
authority (in
Dictio II) the independence of the
Holy Roman Empire from the
Papacy and the emptiness of the prerogatives alleged to have been usurped by the Roman pontiffs. A number of Marsilius's views were declared to be heretical by Pope John XXII in 1327.
[4]
Most of
Defensor pacis is devoted to theology. Relying heavily on Scripture, Marsilius seeks to show that Jesus did not claim to possess any temporal power and that he did not intend his church to exercise any.
[5] On the contrary, Scripture teaches that the church should be thoroughly subordinate to the state in both secular and spiritual matters. All authority in the church lies with the whole body of the faithful, the secular ruler who acts as the people's representative, and general councils called by the secular ruler.
[6] Some of Marsilius's arguments on these themes had a marked influence during the Reformation.
[7]
Today, Marsilius's
Defensor pacis is best remembered not for its theology but for its political philosophy and legal theory. Marsilius agrees with Aristotle that the purpose of government is the rational fulfillment of humans' natural desire for a "sufficient life".
[8] However, he goes beyond Aristotle in embracing a form of republicanism that views the people as the only legitimate source of political authority. Sovereignty lies with the people, and the people should elect, correct, and, if necessary, depose its political leaders.
[7] Democracy, Marsilius argues, is the best form of government because it tends to produce the wisest laws, protects the common benefit, promotes "sufficiency of life", and produces laws that are most likely to be obeyed.
[9]
Marsilius of Padua - Wikipedia
But let's also not forget all the nasty bits... Humanism kept the good and replaced the bad with better, non-christian, things.
That can be done with any religion, not just christianity.
Yet strangely enough it didn't really happen in all of these other religions, and humanism is remains largely the preserve of the post-Christian West.
We could think about the 'nasty bits' of the Enlightenment too, but that doesn't negate the positive contributions.
So I think it's unfair to hold christianity up as some kind of catalyst or source for moral values in today's world.
Humanism didn't emerge from a vacuum, so we look at the society in which it emerged.
An overview here if you are interested:
Review - Tom Holland "Dominion: The Making of the Western Mind" - History for Atheists
No, the morality of humanism is by and large the work of thinking humans and moral development.
Humanists tend to think that their values are 'natural' and 'universal' and that they had to emerge due to 'progress' (the Idea of Progress also has roots in Christianity, as noted even by Enlightenment atheists like Condorcet), but they are grounded in myth as all ideological systems are.
