Reality and Knowledge Epistemology (the study of knowledge) has occupied philosophers and laypeople alike for as long as human beings have had a conception of reality and knowledge. Many philosophers, beginning with Plato, have argued that reality and knowledge are essentially abstract concepts. Aristotle argued, in contrast that knowledge and reality must be based on the senses and inductive reasoning, while Hume argued that our understanding of reality and causation is fundamentally flawed, and that skepticism was the only workable way to knowledge of the world and the internal self. The philosopher George Berkeley presented what is perhaps the most extreme argument against an Aristotelian view of reality in arguing that the material world does not exist, and that objects are simply made of up ideas. While Berkeley's view of reality as based solely upon the mind is extreme and somewhat tenuous, Hume's understanding of the limitations causality and human understanding seems to have real merit. Essentially, we cannot totally rely on our five senses to gain knowledge of the external world.

All men by nature desire to know," writes Aristotle in his Metaphysics. It is this desire that has driven humankind to attempt to understand the basis of our knowledge about ourselves and the world about us. This desire likely began as soon as human self-insight developed, and has continued to the present day, as movies like the Matrix challenge our conceptions about reality and truth. Great philosophers like Plato, Aristotle, David Hume, and George Berkeley have made important contributions to this study of knowledge and reality. This paper will examine the insights of these philosophers, and their diverse understandings about the limitations of human knowledge and the external and internal world.

Plato, born in 428-7 B.C.E, was perhaps the earliest philosopher in the Western tradition to contemplate the nature of reality. He developed the theory of forms or ideas as the basis of human reality. To Plato, the world that perceive through our senses is only "an imitation of the pure, eternal, and unchanging world of the Forms" (The Internet Encyclopedia of Philosophy, Plato). To Plato, the idea or form of beauty can only be approximated...

For example, a beautiful rose, person, sunset, poem, or song is only an approximation of the true idea or form of beauty itself. No matter how seemingly perfect, each of these cannot quite match the form of beauty, which is perfect beauty. The concept of forms extends to concepts like equality, justice, great and small, and even objects like a bed. Essentially, to Plato, the best human knowledge that we can hope for is our best approximation of true nature, or form. Reality in essence remains hidden from us, and we simply see representations of forms in our everyday experience.
In contrast, Plato's student Aristotle (born 384 B.C.), disagreed with Plato's assertion that the world could only be known in the abstract. Instead, "Aristotle believed that the world could be understood at a fundamental level through the detailed observation and cataloging of phenomenon" (Hooker). It is Aristotle's understanding that we can gain knowledge through empirical observation that is reflected so completely in the modern world's embrace of the scientific method. He relied heavily on the technique of inductive reasoning, where he studied a multitude of examples and then tried to derive fundamental rules and concepts from these studies (Hooker).

For Aristotle, knowledge could be classified into different objects of knowledge, and the relative certainty of knowing these objects. Objects like mathematics allow for a knowledge that is certain all of the time (two plus two always equal four), while other types of knowledge cannot be certain (such as human behavior). Ethics, politics, and psychology are also categorized as this type of uncertain knowledge.

For Plato, change in the world could be understood as variations on imperfect representations of forms and ideas that were constant and unchangeable. However, to Aristotle, the visible world represented reality, and to explain change Aristotle had to describe principles that would explain change. For Aristotle, reality and knowledge were based upon an understanding of the root causes of change. In his thinking, there are four basic causes of change and motion in the universe. These are: 1) the material, 2) the formal, 3) the efficient, and 4) the final.…