Kant: 'That all our knowledge begins with experience there can be no doubt. For how is it possible that the faculty of cognition should be awakened into exercise otherwise than by means of objects which affect our senses, and partly of themselves produce representations, partly arouse our powers of understanding into activity, to compare, to connect, or to separate these, and so to convert the raw materials of our sensuous impressions into a knowledge of objects, which is called experience?'