Enlightenment began with an unparalleled confidence in human reason. The new science's success in making clear the natural world through Locke, Berkeley, and Hume affected the efforts of philosophy in two ways. The first is by locating the basis of human knowledge in the human mind and its encounter with the physical world. Second is by directing philosophy's attention to an analysis of the mind that was capable of such cognitive success. John Locke set the tone for enlightenment by affirming the foundational principle of empiricism: There is nothing in the intellect that was not previously in the senses. Locke could not accept the Cartesian rationalist belief in innate ideas. According to Locke, all knowledge of the world must ultimately rest on man's sensory experience. The mind arrives at sound conclusions through reflection after sensation. In other words the mind combines and compounds sensory impressions or "ideas" into more complex concepts building it's conceptual understanding. There was skepticism in the empiricist position mainly from the rationalist orientation. Locke recognized there was no guarantee that all human ideas of things genuinely resembled the external objects they were suppose to represent. He also realized he could not reduce all complex ideas, such as substance, to sensations. He did know there were three factors in the process of human knowledge: the mind, the physical object, and the perception or idea in the mind that represents that object. Locke, however, attempted a partial solution to such problems. He did this by making the distinction between primary and secondary qualities. Primary qualities produce ideas that are simply consequences of the subject's perceptual apparatus. With focusing on the Primary qualities it is thought that science can gain reliable knowledge of the material world. Locke fought off skepticism with the argument that in the end both types of qualities must be regarded as experie...
