How did New England become so secular and socially liberal?

[Joe Haydn]

The birthplace of Calvinism (the Netherlands) and of Puritanism (New England)

What? New England didn't even exist when Puritanism came about in the Elizabethan era.

[Joe Haydn]

From the beginning New England was both very liberal and very religious. One could even say that liberalism as an ideology would not exist without the Puritan revolution, as much of early liberal philosophy was taken directly from radical Protestant theology, such as its emphasis on individualism and opposition to church hierarchy. In fact, I would argue that the abandonment of Puritan values in the 19th century made New England a much more conservative place, as godly small farmers gave way to profit-seeking businessmen. As to how New England became secular, one might consider that secularists of the 19th century like the National Liberal League were natural outgrowths of Puritanism and held a firm place on the Protestant continuum of the time.

In my view, the real question is how Episcopalianism became so socially liberal. For centuries in both England and America, high church Anglicanism was about as Tory and upper class as you could get. But today, Episcopalians are somehow the most socially liberal church there is. Really mind-boggling if you ask me.

[Joe Haydn]

I've wondered this.  I've also wondered why historically Protestant parts of Europe, such as Holland and Scandinavia, are so secular and liberal.  I wonder if there are overlapping factors for both.

That's a good observation; in my view it has much to do with the strong historical ties between Protestantism and classical liberalism.