Who were the key philosophers that represented the movement towards the secular?
I think that the movement to secularism was evident in many philosophers. Spinoza and Erasmus to name a few. Yet, I feel that the Enlightenment thinkers did the most to advocate a movement from the sacred in terms of governing society to one of individual mind. Voltaire, Rousseau, and Montesquieu were three preeminent thinkers that strongly advocated more along the lines of individual empowerment and rational thought, casting it against the church and the realm of the sacred entering social thought and political devision making. The world view these thinkers held was one steeped in rationality and science. This was a response to the excessive religion they perceived that limited individual capacity as well as the idea of being able to affirm one's own place in the world. These thinkers saw religion as a stifling force, one that placed constraints on individual freedom in the name of the divine and one that actually sought to discredit science. Whether they were accurate in their perceptions, the Enlightenment thinkers believed that religion traded off with science and to affirm the latter meant to devalue the former. I would say that the movement of secularism received its greatest amount of support from the Enlightenment thinkers.