Please provide a summary of the key concepts of John Locke's Essay concerning Human Understanding.
Locke's Essay concerning Human Understanding, first published in England in 1690, was a revolutionary treatise on how humans learn and is considered the foundation of modern psycology.
Disputing Aristotle's belief that there existed certain innate ideas in every culture, Locke argued that humans are born with a tabula rasa, a blank tablet, and that tablet gets filled up by actual observations as a person grows. A person's senses take in impressions of the world as that person experiences the world, and the result is that everyone has a slightly, if not profoundly, different view of the world and a different degree of knowledge. The world, according to Locke, was exactly as one's senses made it appear to be, which means that whatever one observes is one's reality. By extension of this logic, then, each person's reality is slightly different.
Because we understand reality and acquire knowledge through our own observation, Locke believed that we can never, as individuals, understand everything we encounter completely and that we have to realize that everyone, as I noted above, will understand knowledge in a slightly different way. In other words, complete knowledge of the world, because no one individual can sense enough to gain complete knowledge, was just not an attainable goal for humans.
Locke's Essay Concerning Human Understanding is, in the words of its author, an attempt to "enquire into the origin, certainty, and extent of human knowledge." Its primary argument, as he explains in the second chapter of the book, is that human knowledge is not "innate," but rather derived from our interactions with the outside world. Locke argued that the human mind was, at birth, a "tabula rasa," or "blank slate," which our observations and sensory experiences filled with information. Our knowledge and understanding are essentially derived from reflection on this information. Locke's Essay ran counter to the claims of many influential thinkers, ranging from Plato to, in more recent times, Decartes. It had been a commonplace among Western philosophers that people were born with innate (usually seen as God-given) understandings that they used to organize their interactions with the world. Where Plato claimed that our understandings of basic concepts were somehow represented concepts, or "ideas" that were inherent to things, Locke argued that these ideas were formed by our observation of similarities between like objects. While not universally accepted, his views on human understanding became the foundation of "empiricism," which emphasized the importance of observation and inductive reasoning.