The thinkers of the Enlightenment, influenced by the scientific revolutions of the previous century, believed in shedding the light of science and reason on the world in order to question traditional ideas and ways of doing things. The scientific revolution (based on empirical observation, and not on metaphysics or spirituality) gave the impression that the universe behaved according to universal and unchanging laws (think of Newton here). This provided a model for looking rationally on human institutions as well as nature.