David Hume was an imperialist philosopher who revolutionized scientific argument and methodology with his skepticism. His arguments about the way people though up to his day, and still today, are fundamental in explaining how we gain knowledge and what we do with this knowledge. Hume helped pave a road leading toward a higher state of consciousness for humanity with his theory concerning the perceptions of the mind. He divided the minds perception into two distinct group's impression and ideas. With these two classifications Hume rationalized the depths of human understanding. Impressions consist of the perception regarding all that is seen, felt and heard. Ideas are formulated thoughts based upon impressions. They are the perceptions of the mind involved with thought rather than experience. Hume used impressions to test the relevance of ideas through his "microscope" system. This theory challenged the mind to test out inconsistent ideas by means of the impressions. The essence of ideas and impression defines the nature of the mind and all that it perceives. Together they rationalize clear and distinct thoughts and sensations Impressions are lively perceptions that implore all the sensation and emotion that the mind perceives. They are not misleading, for their essence is based entirely on experience. It is a perception that ignites the way all is felt, seen, or heard. External causes or objects effect the senses, influencing the way the mind perceives things. For instance to understand the essence of a rose is to recognize that it is red, the pedals feel like silk, it smells of sweet perfume and it evokes happiness. All of these perceptions are derived from the senses. Beautiful words could never conjure enough realism to replace the reality of seeing a rose. A poem written by Ernest Hemmingway describing the beauty of a rose would still act as a dull substitute for the actual experience.