There are two problems with both Stark's analysis (which I am looking forward to reading)
and Stillman's:
        1.  They treat "christianity" as a unified phenomenon  
        2.  They fail to distinguish between the adoption of rationality by individuals
belonging to the elite, and the adoption of rationality by a whole culture (specifically,
by those classes in the culture which did NOT belong to the elite).
  
The cultural adoption of reason was surely confined to the Protestant part of
Christiantiy? (As distinct from the adoption of reason by individuals and groups belonging
to the elite, which was possible everywhere in the world).
  
What divided Protestantism from both the older Eastern Orthodox Churches and the newer
Roman Catholic Church was that Protestantism created a popular culture of literacy and
debate:
        (a) by teaching the general populace to read (earlier, only priests and nobility
were taught to read anything at all), and
        (b) by encouraging the populace not only to read, but in fact to read the Bible
itself and understand it for themselves, and argue about their individual understanding
("schism" is clearly a dirty word for Roman Catholics, but was not seen as a particular
evil, at least by the Radical Reformers, though the Magisterial Reformers did sometimes
act as if it was a problem)
  
In any case, the result was an enormous cultural gulf, not only between the Christian
world and the other parts of the world, but specifically between the Protestant and other
parts of Europe. (I recollect that, in a Roman Catholic school to which I went for part of
my schooling, Roman Catholic students were discouraged from reading the Bible and, if
students objected and insisted, they were "allowed" to read the merely the four Gospels -
and that was in the 1960s!  Student questions were routinely with "That is a mystery!"
BTW, lay Roman Catholics were allowed to read the Gospels only after the Second Vatican
Council, so the school was not unusual in its stance.)
   
What made the enormous cultural gulf possible was that Protestants accepted the
"priesthood of all believers" (that is, they accepted the right of everyone to think for
themselves) whereas the Roman Catholic Church accepted (and still accepts) the priesthood
only of certain special individuals who undergo particular rites and submit to the
intellectual limitations imposed on them by their traditions (expressed by the Pope in
Council, speaking ex Cathedra) - in other words, even priests are not allowed to think for
themselves (they can of course think by themselves, which is a different matter).
  
We may not like Stark's explanation, or Weber's explanation, but the fact remains that the
Protestant parts of Europe became, as it seems to me, the most politically free as well as
the most economically vibrant and scientifically advanced parts of the world till the
1880s, when the USA began to equal them - and the USA was itself culturally formed much
more by Protestantism than by any other culture at least till the election of the first
Roman Catholic President, John F Kennedy, in 1960.
  
Prabhu Guptara