Epistemology – Overview

Epistemology is the branch of philosophy that seeks answers to questions about the possibility and nature of human knowledge. How do we know? What can we know? What are the grounds (or justification) for believing a given piece of knowledge is true? Considering such questions invites more questions about the nature of reality, questions considered in Metaphysics, another branch of philosophy. What can be known depends on what there is, in reality, to be known. These two branches of philosophy have connections. A particular standpoint in epistemology may commit one to a particular metaphysical position, and vice versa. Our focus in this module will be on the main theories of knowledge, rationalism and empiricism. Selected issues about the nature of reality are addressed in the module on Metaphysics.


Successful completion of the Epistemology Unit will enable you to understand and discuss:

  1. The distinctions between:
    • a priori and a posteriori knowledge
    • analytic and synthetic claims
    • how reasoning and experience characterize main schools of epistemology
  1. Rationalism, empiricism, and intuitionism.
  2. The epistemological positions of specific rationalists including Rene Descartes and Gottfried Leibniz and empiricists including John Locke and David Hume.
  3. Hume’s skepticism and how Kant’s transcendental idealism attempts to resolve Hume’s doubt about the possibility of knowledge.


The Course Content for this unit provides the primary reading material, links to any additional assigned reading or viewing resources, and assigned coursework. The unit concludes with a test. Material is presented in these subsections:

2.1 How Do We Know?
2.2 Rationalists and Empiricists
2.3 Rationalists and Empiricists – Continued

Dates for completing all assigned work are in the Schedule of Work.

Philosophers We Will Meet

In our investigation and readings for Epistemology, we will encounter the work of these philosophers. You may select a name here to link to a short biography, or you may link to the same information at your first encounter of the philosopher’s name in the Course Content:

Rene Descartes
John Locke
Gottfried Leibniz
David Hume
Immanuel Kant

Key Terms

It is important to understand the meaning and use of these terms.

a posteriori: Requiring sensory experience of the world. An a posterioriproposition can be known only after experience. (Latin “from what comes after”)
a priori: Requiring no sensory experience of the world. An a priori proposition can be known independently of and prior to experience. (Latin “from what comes before”)
Analytic: Refers to a proposition being true based on what its words mean; it is true by definition. No experience of the world is required to justify.
Empiricism: Reliance on experience as the source of ideas and knowledge.
Innate idea: Mental contents that are presumed to exist in the mind prior to and independently of any experience.
Intuitionism: A theory of knowledge that is a variety of rationalism in which knowing relies on non-inferential mental faculties, rather than reasoning, and not on sensory experience. One “just knows.”
Rationalism: Reliance on reason as the only reliable source of human knowledge.
Skepticism: The theory that certain knowledge is impossible, or that we must doubt what we think we know.
Synthetic: Refers to a proposition requiring experience of the world to be known. Justification depends on the way the world actually is.
tabula rasaThe idea that the mind of an individual begins without any mental content and all knowledge comes from experience. (Latin for “blank slate.”)
Transcendental Idealism: Kant’s theory of knowledge that maintains that synthetic a priori judgments are possible and provide the basis for truths about the world that are both necessary and universal. Knowledge is acquired by connecting concepts of our understanding to our experiences.