I was mainly looking at how the Reformation challenged the dominion of the Catholic Church and how the Enlightenment's propagation of ideas such as republican government and social contract theory challenged the absolute monarchism and divine right to rule that was prevalent in Europe. That's what I meant by challenging traditional authorities.
Republicanism is almost entierly absent from Enlightement's philosophy. You'd struggle hard to find any other mention of republicanism in the XVIIIth's philosophes text that wouldn't systematically point it's not fit for their era, or at best for only small territories.
One could argue that republicanism is the by-product of Enlightement (which I wouldn't really agree, giving that most of the late Enlightement or post-englightement philosophers quickly cut ties with it), but the direct legacy of political situation (in XVIIth England and XVIIIth France alike), without much ideological support on this institutions (safe, for France, more or less abusive call on rousseauist concepts as sovereignity, applied institutionally).
There's a huge difference with Reformation, which, almost from the start, attacked Rome's domination : Enlightement philosophers were closer to pythagoricians or even platonicians in that they searched to strengthen a just political power in face of "fanaticism", trough enlightened interventionism (which could go "englightened despotism" road), when Protestants tried to win over the support of traditional elites (on which they were dependent for political survival) not to propose breaking out clerical dominion, but to replace it.
Can you imagine Luther being in the service of Rome, as Voltaire was for Catherine of Russia?
Or Voltaire getting the support of parlementarians, going against oppressive royal power?
While not linking both phenomenas would be wrong, making them alike is baseless : we're adressing two different dynamics, with very different philosophical or political basis.
I was referring to Protestantism bucking the authority of the Pope instead of temporal rulers, some of whom converted from Catholicism to Protestantism following the Reformation.
Which is hardly challenging traditional authorities : it's rather a matter of challenging a traditional authority with the support of another, closer, one.
Not that Protestantism was the only late medieval/early modern group challenging pontifical authority : even the most Christian king of France never really leaved that out (while kicking Protestants in the theeth in the same time)
Pinning the emergence of the Enlightenment solely on the printing press leaves out a number of crucial factors unrelated that technological advancement.
Leaving out Humanism as a philosophical school is a really crippling mistake IMO. Its developpment was closer to Enlightement, enough to allow comparisons.
I'd point out societal (decline of universities in the XVth, for instance, altough it's more of a dialectic relation there), and political (rise of bureaucratized courts) as one of the explanation of Humanism in Renaissance.
And that's where printing press played a major role, as it allowed a quick, but more importantly less institutionally scrutined intellectual devellopment; at the expense of scholar institutions as universities or church; at the benefit of a more individual-based network (
La République des Lettres) on which political power could intervene much more easily.
By making Reformation the crib of Enlightement, one can't understand why Humanists as Erasmus went more and more away from it, while humanist movement was one of the cause of Reformation development (especially on new biblical studies, and secularized critic of the Church).