Epistemology is the branch of philosophy that studies knowledge, including how human beings know, the extent of what they can know, the certainty of human knowledge and the differences between human knowledge and animal knowledge. Major philosophers in the field of epistemology include Plato, Aristotle, Thomas Aquinas and Descartes.
The word "epistemology" may originate from the Greek words "episteme" and "logos," meaning "knowledge" and "science of," respectively. Although epistemology gradually came to dominate philosophical investigation, it is actually one of the last branches of philosophy to emerge as a distinct branch.
Examples of questions that fall under the domain of epistemology include the following: Are human beings able to arrive at certain knowledge? Is there such a thing as absolute truth that can be known by the intellect? What are the degrees of validity among different types of knowledge? Where does knowledge come from? What is the relationship between knowledge and the soul? All of these question have bearing on other branches of philosophy and, in fact, on all other branches of knowledge.
Philosophers have taken a wide range of positions on these topics, ranging from radical skepticism about the ability of the human mind to know truth to belief in the accessibility of absolute truth.