Leibniz had a strange relationship with Spinoza.  Because of Spinoza’s almost universally reviled status as an arch-atheist of the worst colors, Leibniz had to publicly take every opportunity to discredit him, but secretly he was fascinated by the Dutch philosopher.  He went out of his way to visit Spinoza, and would never reveal fully the conversation that passed between the two.  Leibniz was essentially a hyper-ambitious courtier, who didn’t have the luxury of radical opinions, but he was also perhaps the most brilliant man in Europe at the time, and couldn’t help but note the soundness of Spinoza’s forbidden thought, if only in private.   – Count DvL