Aspects of Epistemology

Once, Zhuang Zhou dreamed he was a butterfly, a butterfly flitting and fluttering about, happy with himself and doing as he pleased. He didn’t know that he was Zhuang Zhou.Suddenly he woke up and there he was, solid and unmistakable Zhuang Zhou. But he didn’t know if he was Zhuang Zhou who had dreamt he was a butterfly, or a butterfly dreaming that he was Zhuang Zhou. Between Zhuang Zhou and the butterfly there must be some distinction! This is called the Transformation of Things. (24)


What is knowledge? How do we know? How do we know we know? What knowledge is scientific? Is this the only knowledge that is truth?

As you may recall from earlier modules, epistemology is the field of philosophy that deals with knowledge and the distinction between knowledge and opinion. Although this definition seems clear enough, when we begin digging deeper, as we will in this module, we discover that people do not actually agree at all about what knowledge is or how to acquire it.

The first section of this module will outline several answers to the questions regarding knowledge and how we come to know.

In the second section, we will explore a specific aspect of epistemology within the branch of philosophy known as the philosophy of science. (1)

How Do We know? Modern Philosophy

Rationalism and Empiricism

In Modern Philosophy, the foundational methods and formulations advanced to address issues in epistemology are rationalism and empiricism .

Rationalism is the epistemological theory that significant knowledge of the world can best be achieved by a priori means and that reason (Lat. Ratio ) is the only reliable source of human knowledge.

Empiricism is the epistemological theory that genuine information about the world must be acquired by a posteriori means, so that nothing can be thought without first being sensed. Reliance on experience is the source of ideas and knowledge. (25/26)

The rationalists are represented by such philosophers as:

  • René Descartes (French, 1596–1650)
  • Benedictus de Spinoza (Dutch, 1632–1677)
  • Gottfried Wilhelm Leibniz (German, 1646–1716)

The empiricists are represented by such philosophers as:

  • John Locke (British, 1632–1704)
  • George Berkeley (Irish, 1685–1753)
  • David Hume (Scottish, 1711–1776)

You can learn more about these ideas from Assembled Western philosophers (1/27)