When Alexander Mack first arrived in Pennsylvania, he could not speak English. Yet the intellectual curiosity and "enlightened" atmosphere of Philadelphia did not escape his attention. The scientific pursuits of Benjamin Franklin exemplified the mood of the time. Mack was not insulated from this, and wrote in his Bible:
The learned astronomers write that the sun is 166 times larger than the entire earth and that the sun is 187,000 miles in distance above the earth and that the planet Mercury is twenty-two times larger than the earth and is many thousands of miles in distance above the earth. Oh, what a wonderfully great incomprehensible Creator must He be who had created and sustained such creations.
Social patterns which affected Mack's growth at this time were much more equalitarian and accepting of diversity than any Mack had experienced in either Germany or Holland. ... It is not surprising that Mack modified his strict in-group stance under the influence of such patterns. It may be further assumed that Mack's own probing of the mind of Christ led him to a more accepting and loving attitude toward non-Brethren and those who differed with him.
Source: Counting the Cost: The Life of Alexander Mack, by William G. Willoughby