The Cambridge Platonists used the framework of the "philosophia perennis" of Agostino Steuco, and from it argued for moderation. They believed that reason is the proper judge of disagreements, and so they advocated dialogue between the Puritan and Laudian traditions. The orthodox English Calvinists of the time found in their views an insidious attack, by-passing as it did the basic theological issues of atonement and justification by faith. Given the circle's Cambridge background in Puritan colleges such as Sidney Sussex College, Cambridge and Emmanuel College, Cambridge, the undermining was intellectually all the more effective. John Bunyan complained in those terms about Edward Fowler, a close latitudinarian follower.